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00:00:00 Colonizing other planets is like the ultimate cosmic adventure.
00:00:04 It's a challenge that's captured the imagination of humans for centuries,
00:00:08 and it's something we've always dreamed of doing.
00:00:11 One of the most popular candidates for this role is Mars, and this isn't surprising.
00:00:17 Mars is a rocky planet that is similar to Earth in many ways,
00:00:21 and it even has evidence of water on its surface.
00:00:24 This makes it a prime candidate for human colonization.
00:00:27 Many scientists and engineers are working on plans to send humans to Mars
00:00:32 and establish a permanent settlement there.
00:00:35 But what about the other candidates?
00:00:39 There are many planets and moons in our solar system, so why not colonize something else?
00:00:44 For example, Ceres.
00:00:47 Ceres is the ultimate cosmic treasure trove.
00:00:51 It's a dwarf planet, not a full-fledged one, just like Pluto.
00:00:54 It's located in the asteroid belt between Mars and Jupiter.
00:00:58 This dwarf planet is the closest to the Sun, and it's adorably tiny.
00:01:03 The entire planet is about the same size as the state of Texas.
00:01:07 So why choose it?
00:01:10 Because Ceres may be a rich source of valuable resources.
00:01:15 The surface of Ceres is covered in craters and other geological features,
00:01:21 and scientists believe that beneath its surface, it has a thick layer of water ice,
00:01:27 which means that deep underground, it may have an ocean of liquid water.
00:01:32 If this is true, Ceres could be a valuable resource for future space missions.
00:01:37 It could potentially provide a source of water for human exploration of the solar system.
00:01:42 So, can we colonize it?
00:01:46 And if so, how do we do that?
00:01:49 Actually, many scientists and space enthusiasts have proposed this idea.
00:01:54 To colonize Ceres, we'd have to use the same methods used to establish colonies on the Moon,
00:01:59 Mercury, and the satellites of Jupiter and Saturn.
00:02:03 Don't worry, it's not that hard.
00:02:06 We just need to figure out how to adapt to a very thin atmosphere,
00:02:10 to extreme temperatures, and pressure, and, well, all the other nasty stuff.
00:02:17 But let's stay hopeful.
00:02:19 At the end of the day, it all comes down to resources.
00:02:22 We'll need water, minerals, silica, and other raw materials.
00:02:26 All this would help us to create a self-sufficient colony.
00:02:30 And luckily, Ceres is full of these things.
00:02:33 So, first of all, we could locate the places of residence inside the craters of Ceres.
00:02:39 We could build domes there that would protect us from all sorts of dangerous things, like radiation.
00:02:46 We could also mine regolith in the asteroid belt.
00:02:49 Regolith is a residual soil that appears as a result of cosmic weathering of the rock.
00:02:55 Basically, it's something like the surface layer of soil on the Moon.
00:02:59 Why do we need it?
00:03:02 Well, because we could use it to 3D print the base layers next to the ice,
00:03:07 so that our bases would be located near the water.
00:03:10 We could then use these base layers to print other structures, like houses.
00:03:16 We could also collect ice and organic molecules to create water.
00:03:21 And by combining water with regolith, we would get soil in which we could grow plants and food.
00:03:27 Wonderful!
00:03:28 There's also another option.
00:03:32 A colony could be created underground.
00:03:35 That is, right next to the icy crust of the planet.
00:03:38 Now, if in the future we'll be some kind of super cool scientists,
00:03:44 we could try to accelerate the rotation of Ceres.
00:03:47 Which sounds crazy, but would be pretty beneficial.
00:03:51 It would help us to create artificial gravity inside the underground colonies.
00:03:56 And speaking of gravity, all of these things may sound cool,
00:04:01 but let's discuss the difficulties that lie ahead of us during colonization.
00:04:05 To colonize Ceres, we would need to overcome a number of challenges.
00:04:13 To begin with, we need to develop technologies that will help us even get to Ceres.
00:04:18 We need some kind of ships that would be capable of long flights into deep space.
00:04:23 For them, first we need to create some kind of nuclear thermal or nuclear electric traction,
00:04:30 and maybe an even more advanced type of fuel.
00:04:33 Then we'll also need technology to help us sustain life in this small rocky world.
00:04:40 That is, tools to extract and use local resources.
00:04:44 Also, since there's no atmosphere on Ceres,
00:04:48 we would have to wear spacesuits and live in pressurized habitats.
00:04:52 And this is only the beginning.
00:04:55 Living on the planet itself won't be an easy task either.
00:04:58 For example, what about extreme temperatures, or radiation,
00:05:03 or the mentioned incredibly weak gravity?
00:05:07 The latter is definitely one of the biggest problems.
00:05:10 The gravity of Ceres is only 3% of the Earth's.
00:05:13 You wouldn't want to accidentally fly into outer space while playing football, would you?
00:05:18 But the fact that any jump could send you on an endless journey isn't the only problem.
00:05:24 Even if you somehow stay on the surface of the planet,
00:05:27 you'll experience the same symptoms and problems as astronauts
00:05:31 who hang out on the International Space Station.
00:05:34 For example, loss of muscle mass, decrease in bone density,
00:05:38 deterioration of vision, problems with the cardiovascular system.
00:05:42 Wow, who would have thought that gravity is so important?
00:05:46 So therefore, if we wanted to survive on Ceres,
00:05:50 we would need either a bunch of doctors, or some kind of artificial gravity.
00:05:55 And don't even get me started on how low gravity will slow down production and work.
00:06:01 And of course, we can't go anywhere without discussing money.
00:06:06 Colonizing Ceres would cost us a huge expense,
00:06:09 especially taking into account all of the above.
00:06:12 And yet, despite all these things,
00:06:16 Ceres still stays one of the best candidates for colonization.
00:06:20 For example, Ceres contains lots of methane and ammonia.
00:06:25 They can be used as a manufactured fuel, or a nitrogenous gas,
00:06:30 or you can just mine it there in order to colonize Mars and Venus.
00:06:34 Even low gravity has its advantages.
00:06:39 Thanks to it, it will be very easy to launch spacecraft from Ceres.
00:06:43 We'll waste much less fuel,
00:06:45 which means that transportation from Ceres to other planets
00:06:48 would be much cheaper and more efficient.
00:06:51 So, even if Ceres doesn't become our permanent residence,
00:06:56 it can become a good transport hub,
00:06:58 something like a spaceport.
00:07:00 We could use it as a base for mining all sorts of useful things from the asteroid belt.
00:07:06 Then, we could transport all these resources back to Mars or Earth.
00:07:11 And it can also become a refueling station for ships
00:07:15 traveling further beyond the solar system.
00:07:17 Sounds cool and pretty sci-fi-ish, doesn't it?
00:07:20 But it seems that any attempts to create a permanent base in the asteroid belt
00:07:26 will have to wait.
00:07:28 Colonizing other planets is a difficult and complex task.
00:07:32 It will require the cooperation and expertise of many different people,
00:07:36 and it will involve developing new technologies
00:07:39 and overcoming many challenges.
00:07:41 Before we go to Ceres,
00:07:44 we need to build infrastructures on the Moon, Mars, and somewhere in between.
00:07:49 Otherwise, any attempts to colonize it would be prohibitively expensive
00:07:53 and would most likely fail before future missions could even reach it.
00:07:57 But the more colonies we create,
00:08:01 the more likely it is that sooner or later,
00:08:03 we'll build another one on Ceres.
00:08:06 This would not only open the asteroid belt to economic exploitation,
00:08:09 it would also serve as a stepping stone to the outer solar system.
00:08:13 This, in turn, could lead to colonizing the moons of Jupiter and beyond.
00:08:20 In other words, the rewards of colonizing Ceres could be great.
00:08:24 Not only would it allow us to explore and understand this fascinating world,
00:08:28 but it could also provide us with valuable resources
00:08:32 that could help us to further explore and settle the solar system.
00:08:36 Life on Ceres would likely be challenging, but exciting,
00:08:39 as humans would be making a new home for themselves
00:08:42 and exploring the mysteries of the universe.
00:08:45 Just imagine all the new planet-themed restaurants and shops we could have.
00:08:49 Welcome to Ceres Mart, where everything is out of this world!
00:08:54 So, if you're a fan of cosmic treasure hunts,
00:08:58 Ceres is surely a rich and rewarding destination.
00:09:01 Just make sure you bring some weights on your feet, so you don't fly anywhere.
00:09:06 It's normal for planets to be a bit tilted on the side.
00:09:12 The Earth is tilted at a 23-degree angle.
00:09:15 That's why we have seasons.
00:09:16 It's summer when the part of the world where you are leans closer to the Sun.
00:09:20 It works the opposite way too.
00:09:22 It's winter when you lean away from it.
00:09:24 But Uranus is tilted more than normal.
00:09:26 It lies at a 98-degree angle, which has a huge effect on its seasons.
00:09:31 Each season on Uranus takes 21 years to play out.
00:09:35 Something to think about the next time we complain that winter lasts forever.
00:09:39 Now, here on Earth, we measure distances in minutes and hours, maybe even days.
00:09:44 It takes 10 minutes to walk to your best friend's house,
00:09:47 or 15 minutes to drive to your favorite cafe.
00:09:50 But in space, it's different.
00:09:52 It's vast, which means we measure how long it takes to get to a certain point in years,
00:09:57 or in most cases, light-years.
00:09:59 So, if you want to walk to the Moon one day,
00:10:02 that would take you 9 years to span the 239,000 miles.
00:10:06 Perhaps you'd like to take a ride to the nearby star, Proxima Centauri.
00:10:10 Maybe if you kept the pedal to the metal at a constant speed of 70 mph,
00:10:15 you'd get there in about 356 billion hours, or around 40.5 million years.
00:10:21 Trust me, after the first 20 million years,
00:10:24 you'd be second-guessing yourself as to why go there in the first place.
00:10:27 Mars contains the biggest valley, Valles Marineris, we've discovered so far.
00:10:32 It's a pretty impressive system of canyons, 2,500 miles long.
00:10:37 That's five times longer than the Grand Canyon.
00:10:40 Researchers first spotted it back in the 1970s.
00:10:43 A bank of volcanoes located on the other side of the canyon ridge
00:10:47 probably helped form this valley.
00:10:49 We haven't discovered a planet completely made of diamonds yet,
00:10:52 but on some planets, it actually rains diamonds.
00:10:56 On Jupiter and Saturn, gas giants of our solar system,
00:10:59 lightning storms turn abundant methane into soot, which we also know as carbon.
00:11:04 The soot falls and transforms into graphite.
00:11:07 Further graphite transforms into diamonds with a diameter of about 0.4 inches.
00:11:13 Now, before you start figuring out how to book a diamond-collecting field trip,
00:11:17 know that these diamonds don't last.
00:11:19 After they enter the planet's core, they melt.
00:11:22 Ever notice how when you're stargazing two nights in a row at the same time,
00:11:26 let's say 9 p.m., the stars stay in the same place, but the moon doesn't?
00:11:31 Well, there are two reasons for that.
00:11:33 First, it depends on what time you go stargazing.
00:11:36 For instance, if you go outside at 8 p.m., and tomorrow you look for it at 11 p.m.,
00:11:41 you'll see the moon in two pretty different places.
00:11:44 In this case, even the stars take different places in the sky since our planet is spinning.
00:11:50 As you know, it takes 24 hours for it to make one full circle.
00:11:54 That means, from our point of view, it seems like both the sky and everything up there
00:11:58 is just moving around us one time per 24 hours.
00:12:02 In the same way, the sun changes its position, rising and setting every day.
00:12:07 So, if you went outside two nights in a row at the same hour, in most cases,
00:12:11 you'll have to wait for an extra half hour or more until the moon gets back to the same position as the night before.
00:12:18 The stars are pretty much standing still.
00:12:20 It seems like they're moving, but that's because the Earth is spinning.
00:12:23 But the moon is actually moving around our planet and goes through different phases.
00:12:28 For example, a new moon is when it's completely dark in the sky.
00:12:32 A full moon is when its day side is facing the Earth.
00:12:35 It takes approximately a month for it to finish one circle around the Earth.
00:12:40 Maybe you'd be luckier on a diamond-collecting expedition on this next planet,
00:12:44 40 million light-years away from Earth.
00:12:46 Scientists used to call it a "super-Earth."
00:12:49 Now, a super-Earth is generally a planet way bigger than ours.
00:12:53 This planet, for example, is double the Earth's size.
00:12:56 It's so close to its star that it makes a full circle around it in less than 18 hours,
00:13:01 which means a year there is pretty short.
00:13:04 Since it's so close to its star, its temperature goes up a whopping 4,900 degrees Fahrenheit.
00:13:10 Because of the heat, in combination with the planet's density,
00:13:14 scientists have the theory that its core is made of carbon in the form of graphite and diamonds.
00:13:20 Over 10 years ago, astronomers discovered a huge water vapor cloud.
00:13:25 It's 12 billion light-years from our home planet.
00:13:28 That cloud is the biggest source of water we know of.
00:13:31 It's also the oldest, dating back to when the Universe was only 1.6 billion years old.
00:13:36 Now it's 13.8 billion years old.
00:13:39 Man, if only I had started a savings account 12 billion years ago!
00:13:43 With compound interest, I'd have made quite a pile of cash by now.
00:13:47 But I wasn't around then.
00:13:49 Anyway, this cloud is so large it holds 140 trillion times the amount of water in all the oceans on our planet.
00:13:57 This cloud kind of feeds a black hole.
00:14:00 It may also contain enough gases, such as carbon monoxide,
00:14:03 to encourage the black hole to grow 6 times bigger than it is at the moment.
00:14:08 The average temperature of our planet is about 57 degrees Fahrenheit.
00:14:12 And the highest temperature ever measured was 134 degrees.
00:14:16 Sound too hot?
00:14:18 Well, on Venus, it can go up to 900 degrees, which makes it the hottest planet in our solar system.
00:14:24 It's not hot enough to melt steel, though.
00:14:26 It would need to be higher by 2,500 degrees to get there.
00:14:30 But it's hot enough to melt lead.
00:14:32 And it's way too hot to sustain life, at least not in any form that we know.
00:14:37 Venus is not even the closest to the Sun.
00:14:39 It's Mercury.
00:14:40 But it has a super-thick atmosphere that traps greenhouse gases.
00:14:44 It's like you covering yourself with a pretty thick blanket in the middle of the summer.
00:14:49 Now, we're used to seeing volcanoes spewing hot molten lava.
00:14:53 After all, that's what they mostly do on Earth.
00:14:55 But in space, volcanoes tend to spew methane, water, or ammonia.
00:15:00 And these materials freeze as they erupt and eventually transform into frozen vapor and something called volcanic snow.
00:15:08 I'm talking about cryovolcanoes here.
00:15:11 You can find them on Jupiter's moons, Io and Europa, Saturn's moon, Titan, and Pluto.
00:15:17 These volcanoes are especially active on Io, which has hundreds of vents.
00:15:21 NASA vehicles have even captured some of these erupting in real time.
00:15:25 Plumes of frozen vapor coming out of them extended for about 250 miles.
00:15:30 Hey, by the way, they just discovered another moon around Jupiter that might actually be good for farming someday.
00:15:37 It's named EIEIO.
00:15:40 Now, what exactly happens to the light after it disappears inside of a black hole?
00:15:45 Well, a photon is a particle of light.
00:15:48 The event horizon is the boundary of a black hole.
00:15:51 When something, say a photon, crosses the line and enters those boundaries, it can't escape anymore.
00:15:57 But it doesn't mean a black hole destroyed it.
00:16:00 It pulls the photon in rapidly towards its center, where an enormous mass is packed into an infinitely small space.
00:16:07 But we're not sure what happens to photons in such extreme conditions.
00:16:11 It's still one of the biggest mysteries.
00:16:13 Does a black hole destroy the light or not?
00:16:16 Saturn has 82 moons we know about, 53 confirmed and 29 more that are still on the waiting list to be confirmed as actual moons before they get their official names.
00:16:27 And one of the coolest moons might be a 914-mile-wide hunk of rock called Aeapetus.
00:16:34 It's dark on one side and bright on the other.
00:16:37 Its lighter half is 20 times more reflective than the other one.
00:16:40 As it turned out, the bright side is ice.
00:16:43 The dark side is a bit more complicated.
00:16:46 One theory says it's dark because of particles coming from another moon, the one named Phoebe.
00:16:51 Another theory says it could be because of heat.
00:16:54 Since the moon is rotating really slowly, its dark material is absorbing heat, which makes it even darker.
00:17:01 Now, how big do you think a black hole can become?
00:17:04 In theory, we can't find an upper limit to its mass.
00:17:07 But astronomers believe the ultra-massive black holes, or UMBHs, located in the cores of certain galaxies are mostly up to 10 billion solar masses big.
00:17:18 Recently, they even discovered these UMBHs physically can't grow much more than this.
00:17:23 Because, in that case, they would start to disrupt the accretion disks that feed them.
00:17:28 That way, they would kind of stuff the source of new material.
00:17:32 Most people picture the universe as somewhere between aquamarine and pale turquoise.
00:17:37 Even some researchers thought that was the case.
00:17:39 They managed to determine the cosmic color by combining light from more than 200,000 galaxies within 2 billion light-years of our planet.
00:17:47 But the real color is actually closer to beige.
00:17:51 Researchers got it all wrong because there was a bug in the software.
00:17:54 No, really?
00:17:56 It converted the cosmic spectrum into the color our eyes would see if we were exposed to it.
00:18:02 The team defined this color as a "cosmic latte."
00:18:05 Ooh, make that a double-shot low-fat large to go, please!
00:18:09 Venus most likely used to be covered with oceans, from 30 to 1,000 feet deep.
00:18:15 Also, some water was locked in the soil of the planet.
00:18:18 On top of that, Venus had stable temperatures of 68 to 122 degrees Fahrenheit, which, you have to admit, was quite pleasant and not that different from the temperatures on Earth nowadays.
00:18:30 So, what I'm getting at is that for 3 billion years, right until something irrevocable happened 700 million years ago, Venus could've been habitable.
00:18:39 But now, it's not.
00:18:41 The Moon is the second brightest object in our sky.
00:18:45 At the same time, among other astronomical bodies, it's one of the dimmest and least reflective.
00:18:51 Our natural satellite only seems bright because it's so close to Earth.
00:18:55 For comparison, our planet looks much brighter when you look at it from space.
00:19:00 It's because clouds, ice, and snow reflect way more light than most types of rock.
00:19:05 Triton, Neptune's moon, has all its surface covered with several layers of ice.
00:19:11 If this satellite replaced our current moon, the night sky would get 7 times brighter.
00:19:17 Neutron stars are some of the smallest yet most massive objects in space.
00:19:22 They're usually about 12 miles in diameter, but are several times heavier than the Sun.
00:19:27 Oh, and they also spin about 600 times per second, far faster than your average figure skater.
00:19:35 Saturn is the least dense planet in the Solar System.
00:19:39 It has 1/8 the average Earth's density.
00:19:42 And still, because of its large volume, the planet is 95 times more massive than Earth.
00:19:48 A transient lunar phenomenon is one of the most enigmatic things happening on the Moon.
00:19:54 It's a short-lived light, color, or some other change on the satellite's surface.
00:19:58 Most commonly, it's random flashes of light.
00:20:02 Astronomers have been observing this phenomenon since the 1950s.
00:20:06 They've noticed that the flashes occur randomly.
00:20:09 Sometimes they can happen several times a week.
00:20:11 After that, they disappear for several months.
00:20:14 Some of them don't last longer than a couple of minutes.
00:20:17 But there have been those that continued for hours.
00:20:20 The year was 1969, one day before Apollo 11 landed on the Moon.
00:20:26 One of the mission participants noticed that one part of the lunar surface was more illuminated than the surrounding landscape.
00:20:32 It looked as if that area had a kind of fluorescence to it.
00:20:36 Unfortunately, it's still unclear if this phenomenon was connected with the mysterious lunar flashes.
00:20:42 Trash isn't just a problem in Earth's oceans, cities, and forests.
00:20:46 There is a thing called space junk, which is any human-made object that's been left in space and now serves no purpose.
00:20:53 There's also natural debris from meteoroids and other cosmic objects.
00:20:58 There are currently over 500,000 pieces of space debris orbiting the Earth at speeds high enough to cause significant damage if they were to collide with a spacecraft or satellite.
00:21:09 NASA does its best to track every single object to ensure that missions outside Earth can reach their destination safely.
00:21:16 Our Sun is insanely massive. Want some proof?
00:21:20 99.86% of all the mass in the Solar System is the mass of the Sun.
00:21:26 In particular, the hydrogen and helium it's made of.
00:21:29 The remaining 0.14% is mostly the mass of the Solar System's 8 planets.
00:21:35 The Sun's temperature is hotter than the surface of a star.
00:21:39 The surface temperature reaches 10,000 degrees Fahrenheit, but the upper atmosphere heats up to millions of degrees.
00:21:46 If someone could dig a tunnel straight into the center of the planet and out the opposite side,
00:21:51 and you were adventurous enough to jump into it, it would take you 42 minutes to fall to the other side.
00:21:58 You'd speed up as you fell, reaching maximum speed by the time you reached Earth's core.
00:22:04 After the halfway point, you would then fall upwards, getting slower and slower.
00:22:09 By the time you reached the opposite surface, your speed would be back to zero.
00:22:13 Unless you managed to climb out of the hole, you'd immediately start falling again, back down, or up, to the other side of the planet.
00:22:21 This trip would go on forever, all thanks to the weird effects of gravity.
00:22:25 Hey, might be a fun way to spend an afternoon!
00:22:28 There might be more metals, for example, titanium or iron, in lunar craters than astronomers used to think.
00:22:37 The main problem with this finding? It contradicts the main theory about how the Moon was formed.
00:22:42 That theory says that Earth's natural satellite was spun off from our planet after a collision with a massive space object.
00:22:49 But then, why does Earth's metal-poor crust have much less iron oxide than the Moon's?
00:22:56 It might mean the Moon was formed from the material lying much deeper inside our planet.
00:23:01 Or these metals could've appeared when the molten lunar surface was slowly cooling down.
00:23:06 Or maybe, as they've been saying for centuries, it's made of green cheese.
00:23:11 Earth could've been purple before it turned blue and green.
00:23:16 One scientist has a theory that a substance existed in ancient microbes before chlorophyll, that thing that makes plants green, evolved on Earth.
00:23:25 This substance reflected sunlight in red and violet colors, which combined to make purple.
00:23:30 If true, the young Earth may have been teeming with strange purple-colored critters before all the green stuff appeared.
00:23:37 The highest mountain in the Solar System is Olympus Mons on Mars.
00:23:43 It's three times as high as Mount Everest, the Earth's highest mountain above sea level.
00:23:47 If you were standing on top of Olympus Mons, you wouldn't understand you were standing on a mountain.
00:23:53 Its slopes would be hidden by the planet's curvature.
00:23:57 Astronomers have found a massive reservoir of water in space, the largest ever detected.
00:24:03 Too bad it's also the farthest, 12 billion light-years away from us.
00:24:07 The water vapor cloud holds 140 trillion times as much water as all the Earth's oceans combined.
00:24:14 What are we supposed to do with that information?
00:24:17 Venus spins at its own unhurried pace.
00:24:20 A full rotation takes 243 Earth days, and it takes the planet a bit less than 225 Earth days to go all the way around the Sun.
00:24:29 It means a day on Venus is longer than a year.
00:24:33 There's very little seismic activity going on inside the moon.
00:24:37 Yet many moonquakes, caused by our planet's gravitational pull, sometimes happen several miles below the surface.
00:24:44 After that, tiny cracks and fissures appear in the satellite's surface, and gases escape through them.
00:24:50 Hey, they sometimes escape from me, too.
00:24:54 Mars is the last of the inner planets, which are also called terrestrial since they're made up of rocks and metals.
00:25:01 The red planet has a core made mostly of iron, nickel, and sulfur.
00:25:05 It's between 900 and 1200 miles across.
00:25:08 The core doesn't move.
00:25:10 That's why Mars lacks a planet-wide magnetic field.
00:25:13 The weak magnetic field it has is just 1/100th percent of the Earth's.
00:25:20 When the planets in the Solar System were just starting to form, Earth didn't have a moon for the longest time.
00:25:26 It took 100 million years for our natural satellite to appear.
00:25:30 There are several theories as to how the moon came into existence, but the prevailing one is the fission theory.
00:25:38 Somebody went fishing and caught the moon?
00:25:41 Actually, no.
00:25:42 The fission theory proposes that the moon was formed when an object collided with Earth, sending particles flying about.
00:25:50 Gravity pulled the particles together, and the moon was created.
00:25:54 It eventually settled down on the Earth's ecliptic plane, which is the path that the moon orbits.
00:25:59 So, looks like the green cheese is off the table now.
00:26:03 The largest single living thing on Earth turns out to be a mushroom in Oregon.
00:26:08 This enormous honey mushroom lives in Malheur National Forest and covers an area of 3.7 square miles.
00:26:15 It could be as much as 8,500 years old.
00:26:18 You could be forgiven for missing it, though, since most of it's hidden underground.
00:26:24 When the roots of individual honey mushrooms meet, they can fuse together to become a single fungus, which explains how this one got so big.
00:26:33 If you could gather all that mushrooming stuff into one big ball, it could weigh as much as 35,000 tons.
00:26:40 That's about as heavy as 200 grey whales.
00:26:43 Hey, that's a whale of a mushroom.
00:26:46 The largest asteroid in the Solar System is called Vesta, and it's so big that it's sometimes even called a dwarf planet.
00:26:55 A trip to the nearest star, apart from the Sun, would take you 5 million years on a commercial airplane.
00:27:00 That's what I call a long-haul flight.
00:27:04 Space isn't supposed to be black. There are stars everywhere.
00:27:07 Shouldn't they light up everything around?
00:27:10 Well, you don't see stars wherever you look because some of them haven't existed long enough for their light to reach Earth.
00:27:17 A day on Uranus lasts 17 hours, 14 minutes, and 24 seconds.
00:27:22 But get this, the planet has a tilt of around 98 degrees, and that makes a season on the gas giant last 21 Earth years.
00:27:32 Now, some scientists believe that our planet used to have an additional satellite.
00:27:37 According to their research, a small celestial body about 750 miles wide orbited Earth like a second moon.
00:27:44 It most likely crashed into our main satellite later on.
00:27:48 Such a collision could explain why the two sides of the moon look so different from each other, one being heavily cratered and rough.
00:27:55 Or it could be the green cheese.
00:27:59 It's normal for planets to be a bit tilted on the side.
00:28:03 The Earth is tilted at a 23-degree angle. That's why we have seasons.
00:28:07 It's summer when the part of the world where you are leans closer to the Sun.
00:28:11 It works the opposite way too. It's winter when you lean away from it.
00:28:15 But Uranus is tilted more than normal. It lies at a 98-degree angle, which has a huge effect on its seasons.
00:28:22 Each season on Uranus takes 21 years to play out.
00:28:26 Something to think about the next time we complain that winter lasts forever.
00:28:31 Now, here on Earth, we measure distances in minutes and hours, maybe even days.
00:28:36 It takes 10 minutes to walk to your best friend's house, or 15 minutes to drive to your favorite cafe.
00:28:41 But in space, it's different. It's vast, which means we measure how long it takes to get to a certain point in years, or in most cases, light-years.
00:28:50 So, if you want to walk to the Moon one day, that would take you 9 years to span the 239,000 miles.
00:28:58 Perhaps you'd like to take a ride to the nearby star, Proxima Centauri.
00:29:02 Maybe if you kept the pedal to the metal at a constant speed of 70 mph, you'd get there in about 356 billion hours,
00:29:10 or around 40.5 million years.
00:29:13 Trust me, after the first 20 million years, you'd be second-guessing yourself as to why go there in the first place.
00:29:19 Mars contains the biggest valley, Valles Marineris, we've discovered so far.
00:29:24 It's a pretty impressive system of canyons, 2,500 miles long.
00:29:29 That's five times longer than the Grand Canyon.
00:29:32 Researchers first spotted it back in the 1970s.
00:29:35 A bank of volcanoes located on the other side of the canyon ridge probably helped form this valley.
00:29:41 We haven't discovered a planet completely made of diamonds yet, but on some planets, it actually rains diamonds.
00:29:48 On Jupiter and Saturn, gas giants of our solar system, lightning storms turn abundant methane into soot, which we also know as carbon.
00:29:57 The soot falls and transforms into graphite.
00:29:59 Further graphite transforms into diamonds with a diameter of about 0.4 inches.
00:30:05 Now, before you start figuring out how to book a diamond-collecting field trip, know that these diamonds don't last.
00:30:11 After they enter the planet's core, they melt.
00:30:14 Ever notice how when you're stargazing two nights in a row at the same time, let's say 9 p.m., the stars stay in the same place, but the moon doesn't?
00:30:23 Well, there are two reasons for that.
00:30:25 First, it depends on what time you go stargazing.
00:30:28 For instance, if you go outside at 8 p.m., and tomorrow you look for it at 11 p.m., you'll see the moon in two pretty different places.
00:30:36 In this case, even the stars take different places in the sky since our planet is spinning.
00:30:41 As you know, it takes 24 hours for it to make one full circle.
00:30:45 That means, from our point of view, it seems like both the sky and everything up there is just moving around us one time per 24 hours.
00:30:53 In the same way, the sun changes its position, rising and setting every day.
00:30:58 So, if you went outside two nights in a row at the same hour, in most cases, you'll have to wait for an extra half hour or more until the moon gets back to the same position as the night before.
00:31:09 The stars are pretty much standing still.
00:31:11 It seems like they're moving, but that's because the Earth is spinning.
00:31:15 But the moon is actually moving around our planet and goes through different phases.
00:31:19 For example, a new moon is when it's completely dark in the sky.
00:31:23 A full moon is when its day side is facing the Earth.
00:31:26 It takes approximately a month for it to finish one circle around the Earth.
00:31:31 Maybe you'd be luckier on a diamond-collecting expedition on this next planet, 40 million light-years away from Earth.
00:31:37 Scientists used to call it a "super-Earth."
00:31:40 Now, a super-Earth is generally a planet way bigger than ours.
00:31:44 This planet, for example, is double the Earth's size.
00:31:47 It's so close to its star that it makes a full circle around it in less than 18 hours, which means a year there is pretty short.
00:31:55 Since it's so close to its star, its temperature goes up a whopping 4,900 degrees Fahrenheit.
00:32:01 Because of the heat, in combination with the planet's density, scientists have the theory that its core is made of carbon in the form of graphite and diamonds.
00:32:11 Over 10 years ago, astronomers discovered a huge water vapor cloud.
00:32:16 It was 12 billion light-years from our home planet.
00:32:19 That cloud is the biggest source of water we know of.
00:32:22 It's also the oldest, dating back to when the Universe was only 1.6 billion years old.
00:32:27 Now it's 13.8 billion years old.
00:32:30 Man, if only I had started a savings account 12 billion years ago!
00:32:35 With compound interest, I'd have me quite a pile of cash by now.
00:32:39 But I wasn't around then.
00:32:41 Anyway, this cloud is so large it holds 140 trillion times the amount of water in all the oceans on our planet.
00:32:49 This cloud kind of feeds a black hole.
00:32:52 It may also contain enough gases, such as carbon monoxide, to encourage the black hole to grow 6 times bigger than it is at the moment.
00:33:00 The average temperature of our planet is about 57 degrees Fahrenheit.
00:33:04 And the highest temperature ever measured was 134 degrees.
00:33:08 Sound too hot?
00:33:09 Well, on Venus, it can go up to 900 degrees, which makes it the hottest planet in our solar system.
00:33:15 It's not hot enough to melt steel, though.
00:33:18 It would need to be higher by 2,500 degrees to get there.
00:33:21 But it's hot enough to melt lead.
00:33:24 And it's way too hot to sustain life, at least not in any form that we know.
00:33:29 Venus is not even the closest to the Sun.
00:33:31 It's Mercury.
00:33:32 But it has a super-thick atmosphere that traps greenhouse gases.
00:33:36 It's like you covering yourself with a pretty thick blanket in the middle of the summer.
00:33:40 Now, we're used to seeing volcanoes spewing hot molten lava.
00:33:44 After all, that's what they mostly do on Earth.
00:33:47 But in space, volcanoes tend to spew methane, water, or ammonia.
00:33:52 And these materials freeze as they erupt and eventually transform into frozen vapor and something called volcanic snow.
00:33:59 I'm talking about cryovolcanoes here.
00:34:02 You can find them on Jupiter's moons, Io and Europa, Saturn's moon, Titan, and Pluto.
00:34:08 These volcanoes are especially active on Io, which has hundreds of vents.
00:34:13 NASA vehicles have even captured some of these erupting in real time.
00:34:17 Plumes of frozen vapor coming out of them extended for about 250 miles.
00:34:22 Hey, by the way, they just discovered another moon around Jupiter that might actually be good for farming someday.
00:34:29 It's named EIEIO.
00:34:32 Now, what exactly happens to the light after it disappears inside of a black hole?
00:34:37 Well, photon is a particle of light.
00:34:40 The event horizon is the boundary of a black hole.
00:34:43 When something, say, a photon, crosses the line and enters those boundaries, it can't escape anymore.
00:34:49 But it doesn't mean a black hole destroyed it.
00:34:52 It pulls the photon in rapidly towards its center, where an enormous mass is packed into an infinitely small space.
00:34:58 But we're not sure what happens to photons in such extreme conditions.
00:35:03 It's still one of the biggest mysteries.
00:35:05 Does a black hole destroy the light or not?
00:35:08 Saturn has 82 moons we know about, 53 confirmed and 29 more that are still on the waiting list to be confirmed as actual moons before they get their official names.
00:35:19 And one of the coolest moons might be a 914-mile-wide hunk of rock called Aeapetus.
00:35:26 It's dark on one side and bright on the other.
00:35:29 Its lighter half is 20 times more reflective than the other one.
00:35:32 As it turned out, the bright side is ice.
00:35:35 The dark side is a bit more complicated.
00:35:37 One theory says it's dark because of particles coming from another moon, the one named Phoebe.
00:35:43 Another theory says it could be because of heat.
00:35:46 Since the moon is rotating really slowly, its dark material is absorbing heat, which makes it even darker.
00:35:53 Now, how big do you think a black hole can become?
00:35:56 In theory, we can't find an upper limit to its mass.
00:35:59 But astronomers believe the ultra-massive black holes, or UMBHs, located in the cores of certain galaxies, are mostly up to 10 billion solar masses big.
00:36:10 Recently, they even discovered these UMBHs physically can't grow much more than this.
00:36:15 Because, in that case, they would start to disrupt the accretion disks that feed them.
00:36:20 That way, they would kind of stuff the source of new material.
00:36:24 Most people picture the universe as somewhere between aquamarine and pale turquoise.
00:36:29 Even some researchers thought that was the case.
00:36:31 They managed to determine the cosmic color by combining light from more than 200,000 galaxies within 2 billion light-years of our planet.
00:36:39 But the real color is actually closer to beige.
00:36:43 Researchers got it all wrong because there was a bug in the software.
00:36:46 No, really?
00:36:48 It converted the cosmic spectrum into the color our eyes would see if we were exposed to it.
00:36:53 The team defined this color as a "cosmic latte".
00:36:57 Ooh, make that a double-shot low-fat large to go, please.
00:37:17 The sun's heat is beneath our feet.
00:37:20 Scientists have figured out that Earth's core is actually as hot as the surface of the sun, around 10,800 degrees Fahrenheit.
00:37:28 One of the reasons it's so incredibly hot down there is because Earth is still shedding heat from when it was created billions of years ago.
00:37:36 Also, when an object as big as Mars slammed into the young Earth, it not only created the moon, according to one theory, but melted the surface of the planet.
00:37:45 A lot of that extra heat is probably still stored inside the core.
00:37:50 But there's no need to worry.
00:37:52 The planet's core is harder for us to access than it is to probe the surface of Pluto.
00:37:56 In fact, chances are we may never develop technology that could physically reach the core.
00:38:02 There's no air on the moon.
00:38:05 But then, how can it be rusting?
00:38:08 Scientists have discovered the presence of hermitite on the moon, and it's a kind of rust.
00:38:13 A special NASA research instrument examined the light reflected off the moon's surface.
00:38:18 It turned out that the composition of the satellite's poles was very different from the rest of it.
00:38:23 The moon's surface is dotted with iron-rich rocks.
00:38:27 But without oxygen and liquid water, rust can't appear.
00:38:31 Solar winds add to the mystery.
00:38:34 They bombard the moon with hydrogen, and hydrogen makes it much more difficult for hermitite to form.
00:38:40 Even though the moon doesn't have an atmosphere, it still has some trace amounts of oxygen.
00:38:45 Its source is our planet's upper atmosphere.
00:38:48 Earth also protects the moon from almost 100% of solar winds, although not all the time.
00:38:54 And even though our natural satellite is bone dry,
00:38:57 there might be water ice in the shadowed craters on its far side.
00:39:02 A day on Uranus lasts 17 hours, 14 minutes, and 24 seconds.
00:39:09 But, get this, the planet has a tilt of around 98 degrees,
00:39:14 and that makes a season on the gas giant last 21 Earth years.
00:39:19 Mars has two moons, Phobos and Deimos.
00:39:24 In the next 30 to 50 million years, Mars' gravitational forces will tear Phobos apart,
00:39:30 and it will likely result in the formation of a ring around the planet.
00:39:36 The Earth is the densest in the solar system.
00:39:39 At the Earth's center, there's a core that takes up 15% of the planet's volume.
00:39:44 It consists of two parts, the outer and the inner core.
00:39:48 The inner core is a solid ball made of iron and nickel.
00:39:52 Its radius is 760 miles, which makes 20% of the entire Earth's radius and 80% of the moon's radius.
00:40:01 The 1500-mile-thick outer core is liquid.
00:40:05 It also consists of iron and nickel, but it's not under enough pressure to be solid.
00:40:10 Mars houses the biggest volcano in the solar system.
00:40:15 While everything seems to be calm on Mars nowadays,
00:40:18 in the past, some sort of force caused enormous volcanoes to form and erupt.
00:40:24 One of these volcanoes is Olympus Mons.
00:40:26 It's 16 miles tall, which is the height of three Mount Everests,
00:40:31 and 374 miles across, making it about the size of Arizona.
00:40:36 The volcano grew to such a gargantuan size because of the weak gravity on Mars
00:40:41 and the lack of tectonic plate movement.
00:40:43 Gravity is not the same everywhere.
00:40:48 The rocks, metals, and other minerals and substances that make up the planet
00:40:54 are packed into the ground more tightly in certain places than in others.
00:40:58 This has surprising consequences.
00:41:00 Gravity varies slightly depending on where you are.
00:41:03 You weigh 0.5% less standing at the equator than you do at the poles.
00:41:09 In most cases, that's a difference of less than one pound.
00:41:12 How high up you are also has an effect,
00:41:15 so if you were at the top of Mount Everest, you'd also weigh slightly less.
00:41:19 Just don't look down.
00:41:21 Earth's toughest living thing is so small you can't see it.
00:41:26 Water bears, also known as moss piglets, are cute little creatures
00:41:31 with eight legs and squashed-up heads that are less than a hundredth of an inch in length.
00:41:35 Despite their microscopic stature, they can basically survive anywhere.
00:41:40 They prefer bits of wet moss or the bottom of a lake,
00:41:43 but they won't complain if you put them somewhere really uncomfortable.
00:41:47 They can endure extreme cold and incredible heat,
00:41:51 and survive both huge pressure and high radiation.
00:41:54 Some of the little bears once even managed to survive unprotected in outer space
00:41:59 for ten days without a problem.
00:42:01 That is tough.
00:42:03 They handle all these things by rolling up into a ball and hibernating,
00:42:07 which reduces their need for oxygen and food.
00:42:10 The moon's gravity is about 17% of that on Earth.
00:42:15 If you weighed 200 pounds on our home planet,
00:42:18 on the moon, your weight would decrease to a mere 34 pounds.
00:42:22 You would also be able to carry stuff six times heavier than what you can carry on Earth.
00:42:27 It would also be easier to walk on the moon's surface,
00:42:30 but it would be more dangerous, too.
00:42:32 Your feet, inside a heavy spacesuit, would sink into the lunar soil up to six inches deep.
00:42:38 But let's imagine you decided to skip the tedious process of walking by leaping through the air.
00:42:44 Then you'd likely lose control of your jumps in no time.
00:42:48 Plus, the moon's surface is littered with deep craters.
00:42:51 It would be a tough feat to avoid all of them.
00:42:54 You can see solar eclipses because even though the moon is 400 times smaller than the sun,
00:43:00 it's also 400 times closer to Earth.
00:43:03 So it's perfectly capable of obscuring the star.
00:43:06 But in 50 million years, I won't be around then.
00:43:10 The moon won't be able to block the sun completely because of the satellite's changing orbit.
00:43:17 A full NASA spacesuit costs an unbelievable $12 million.
00:43:22 Yeah, I can believe that.
00:43:24 70% of this hefty sum is for the control module and backpack.
00:43:28 At the very center of Uranus, there's a rocky core, small, just half the Earth's mass.
00:43:37 Compared to other planets, Uranus' core is rather cool.
00:43:41 9,000 degrees Fahrenheit.
00:43:43 The ice mantle surrounds the solid core, and that's the largest portion of the planet, about 80%.
00:43:49 It's also not the ice you might be thinking about.
00:43:52 It's a hot, dense fluid made up of water, ammonia, ice, and methane,
00:43:57 sometimes referred to as a water-ammonia ocean.
00:44:01 Uranus' atmosphere is mostly hydrogen and helium,
00:44:04 but it has its blue-green color because of methane gas that absorbs the red light.
00:44:12 The ocean on Jupiter is larger than any other in the solar system.
00:44:16 But unlike Earth's oceans, it's made not of water, but of metallic hydrogen.
00:44:21 The ocean's depth is a mind-blowing 25,000 miles.
00:44:25 That's almost the same as the distance around Earth.
00:44:28 Venus is a champ when it comes to volcanoes.
00:44:33 The planet has about 1,600 major ones, but none of them is known to erupt.
00:44:38 There's a supermassive black hole 250 million light-years away from us.
00:44:43 It hums the deepest sound ever detected from any object in the universe.
00:44:48 It's 57 octaves lower than the Middle Sea on your piano.
00:44:52 That's one quadrillion times deeper than what we can hear.
00:44:56 Mercury is a few billion years old.
00:45:02 In 2016, it was discovered by a group of scientists
00:45:06 that it's getting smaller.
00:45:09 After more research, they found out that Mercury hadn't finished cooling down yet.
00:45:14 There are planets that aren't bound to any star orbit
00:45:19 and aimlessly wander through outer space.
00:45:22 Among the most spectacular-looking space objects are pulsars.
00:45:28 Pulsars are a type of neutron star.
00:45:31 They shoot out some kind of light from the star's core.
00:45:35 They shoot out some of their material almost at the speed of light.
00:45:38 Regular pulsars spin at a reasonable speed,
00:45:41 between 1/10 to 60 times per second.
00:45:45 But millisecond pulsars can spin at an impressive 700 times a second,
00:45:50 which is way too fast for the human eye to even process.
00:45:53 As they spin, they emit a beam of radiation from their axis
00:45:57 that looks like the light from a lighthouse.
00:46:00 Astronomers can notice pulsars when they face Earth,
00:46:03 since it looks like a light being shined on our planet.
00:46:06 When the light shines elsewhere, the pulsar can't be seen.
00:46:10 Our Sun is insanely massive.
00:46:15 Want some proof?
00:46:17 99.86% of all the mass in the solar system is the mass of the Sun.
00:46:22 In particular, the hydrogen and helium it's made of.
00:46:26 The remaining 0.14% is mostly the mass of the solar system's 8 planets.
00:46:32 Saturn's rings are very thin compared to its size.
00:46:37 If you had a scale model of the planet that was 3 feet wide,
00:46:40 the rings would be 10,000 times thinner than a razor blade.
00:46:44 Even though Venus is the hottest planet in our solar system,
00:46:49 it still has snow.
00:46:51 But not what you'd expect.
00:46:53 It snows metals and rains acid.
00:46:55 Not a great vacation spot.
00:46:59 [Music]
00:47:02 Imagine a basketball spinning on someone's finger.
00:47:09 A point near the middle of the ball takes longer to spin back to where it started
00:47:13 than the spot where your finger is.
00:47:15 Earth spins in much the same way.
00:47:17 People in the center of Africa are turning at 1,000 mph as the planet rotates,
00:47:22 while anyone at the South Pole doesn't really move at all,
00:47:26 other than rotating in place.
00:47:28 At the same time, we're all moving forward through space equally fast,
00:47:32 since the planet is also hurtling around the Sun at 67,000 mph.
00:47:37 The temperature at the boundary of our planet's inner and outer core
00:47:41 is 10,800 degrees Fahrenheit.
00:47:44 That's as hot as the surface of the Sun.
00:47:46 And the pressure there is 3.3 million times the atmospheric pressure at sea level.
00:47:52 Two or three years ago, an asteroid was pulled into Earth's orbit
00:47:56 and started to travel around the planet.
00:47:59 Even though it's no larger than an average car, it's still a big deal.
00:48:03 Out of more than one million asteroids astronomers know about,
00:48:06 it's only the second one to orbit our planet.
00:48:09 Called 2020 CD3, it's our temporary mini-moon.
00:48:14 It won't be with Earth for long, though.
00:48:16 The asteroid is following a random orbit and is slowly drifting away.
00:48:21 Temporarily captured objects, such as 2020 CD3, are rare.
00:48:26 They need to have a specific direction and speed
00:48:29 to be caught by Earth's gravitational pull.
00:48:31 Otherwise, they either crash into the planet or fly in another direction.
00:48:37 The movement of galaxies and clusters billions of light-years away from us
00:48:41 suggests there's some enormously massive body outside the visible universe.
00:48:46 After billions of years, the expansion of the universe will make the space so sparse
00:48:51 that we won't be able to see the stars in the sky at all.
00:48:55 The moon isn't a perfect sphere. It's shaped like an egg.
00:48:59 Plus, the satellite's center of mass is a bit more than a mile off its geometric center.
00:49:05 Even though Venus is the hottest planet in our solar system, it still has snow.
00:49:10 But not what you'd expect.
00:49:12 It snows metals and rains acid.
00:49:15 Not a great vacation spot.
00:49:18 Saturn is mostly composed of hydrogen and helium,
00:49:21 with some traces of methane, ammonia, and water.
00:49:25 But it contains more sulfur than Jupiter,
00:49:28 which gives the planet a smog-like orange hue.
00:49:32 On Earth, sound waves make air molecules vibrate,
00:49:35 which is why we're able to hear sound.
00:49:38 Other planets and moons allow sound to travel through mediums
00:49:41 like their atmospheres and oceans, too.
00:49:43 In space, though, it's said that there is no sound,
00:49:47 since there aren't any molecules to vibrate and deliver sound waves.
00:49:51 However, not all researchers agree on this,
00:49:54 given that space isn't just a desolate vacuum.
00:49:57 In between the emptiness, there are clouds of gas and other stray particles.
00:50:01 So, depending on where you are, sound waves can be possible.
00:50:06 Astronomers know for sure that the universe is growing bigger,
00:50:11 and the speed at which it's ballooning is increasing all the time.
00:50:15 But if the whole thing is swelling into something bigger,
00:50:18 then it must have some kind of an edge, right?
00:50:21 It's unlikely that people will ever find out,
00:50:23 but if so, then what would it be?
00:50:26 A ginormous brick wall and then nothing?
00:50:29 An abyss that leads to nowhere?
00:50:31 The most common theory is that the universe is shaped in such a way
00:50:35 that it can't have an edge.
00:50:37 But it's not the only idea.
00:50:39 Another theory is even more difficult to comprehend.
00:50:42 The universe is, indeed, infinite,
00:50:45 and our part of it isn't that unique.
00:50:48 It means that somewhere out there, there's another you,
00:50:51 or rather, other you.
00:50:54 One of them is just a bit shorter,
00:50:56 another wears their hair in a different way,
00:50:58 and the third one is identical to you in all possible ways.
00:51:02 There's also a theory about a multi-universe
00:51:05 that consists of many smaller universes,
00:51:08 and the universe we live in is just a tiny bubble
00:51:11 among other similar bubbles.
00:51:14 Those scientists who support this idea are also sure
00:51:17 that bubble universes can come into contact with one another.
00:51:21 Then gravity starts to flow between them,
00:51:23 and when two or three universes connect,
00:51:25 a big bang occurs,
00:51:27 just like the one that created our home universe.
00:51:31 Neptune is the windiest place in the solar system.
00:51:34 Clouds of frozen methane are whipped across the planet
00:51:37 at a speed of 1,200 miles per hour.
00:51:40 Neptune's core is solid
00:51:42 and consists mostly of iron and some other metals.
00:51:45 Its mass is 1.2 times bigger than that of Earth.
00:51:48 The temperature inside reaches 9,000 degrees Fahrenheit.
00:51:52 Astronomers also believe that at a depth of 4,500 miles,
00:51:57 there might be a diamond layer
00:51:59 where it's raining diamond crystals.
00:52:02 On Earth, people are used to a beautiful sunset
00:52:05 that's painted in hues of orange, red, and yellow.
00:52:08 On Mars, however, the normally pinkish-red sky turns blue
00:52:13 as the sun goes down under the horizon.
00:52:15 It's because Mars is much farther away from the sun than Earth,
00:52:19 making the sunlight less intense.
00:52:21 The fine dust in the Martian atmosphere absorbs the blue light
00:52:25 and gets rid of the warmer colors that you typically see on Earth.
00:52:29 Whether it's blue or yellow, both sunsets look spectacular.
00:52:33 At around a quarter of the size of Earth,
00:52:36 the moon is pretty enormous relative to other satellites out in space.
00:52:40 There's nothing quite like this situation anywhere else in the solar system.
00:52:44 Pluto has a moon that's almost half as big as itself,
00:52:47 but it's more like a twin than a satellite.
00:52:50 There are more than 150 moons in our solar system,
00:52:54 and Earth's is the fifth largest out of the whole lot.
00:52:57 There might be a labyrinth of lava tubes on the moon.
00:53:01 Not long ago, astronomers received the results of an underground lunar topography.
00:53:06 They discovered a massive cave under the satellite's surface.
00:53:10 About 30 miles long and 60 miles wide,
00:53:13 the cave's likely to be the result of 3-billion-year-old volcanic activity.
00:53:18 After streams of lava hardened, they created a thick, hard crust on the outside.
00:53:23 But inside, lava kept flowing, melting the rock and forming tunnels and caves.
00:53:29 Countless pits in the moon's surface discovered by NASA might be the openings to lava tubes.
00:53:35 We can't dig up most of Earth's gold.
00:53:38 99% of it ended up in the center of the planet several billion years ago,
00:53:43 attracted by the iron in Earth's core.
00:53:45 We're talking about 1.6 quadrillion tons of gold here.
00:53:49 That's enough to coat the entire planet's surface in 1.5 feet of the stuff.
00:53:54 And if all those meteorites hadn't later smashed into the ground,
00:53:58 bringing extra amounts of gold, it would be even rarer.
00:54:02 Not so long ago, astronomers discovered a massive blob of some mysterious substance.
00:54:08 It was hidden underneath the surface of the moon's far side.
00:54:12 Its mass was the same as that of a pile of metal five times larger than the Big Island of Hawaii.
00:54:18 The enigmatic something lies almost 200 miles beneath an enormous crater
00:54:23 that appeared on the lunar surface billions of years ago.
00:54:26 The blob likely has something to do with a super collision.
00:54:30 It might be the metal core of the object that hit the moon back then.
00:54:35 Scientists can't wait to lay their hands on the discovery.
00:54:38 It could explain lots of things about the South Pole-Aitken crater,
00:54:42 the largest known in the solar system.
00:54:44 If it was on Earth, its oval-shaped basin would stretch from Washington, D.C. to Texas.
00:54:51 In 2011, astronomers discovered an enormous water reservoir simply floating in space
00:54:57 around a supermassive black hole called a quasar.
00:55:01 Floating water vapors have been found throughout the universe, but they aren't that common.
00:55:06 This particular reservoir holds around 140 trillion times the amount of water in the Earth's oceans.
00:55:13 It's one of the oldest, largest, and, at more than 12 billion light-years away,
00:55:18 one of the farthest things known to humankind.
00:55:22 Astronauts in space can lose about 1% of their muscle mass each month.
00:55:27 To prevent this, they have to stick to an exercise regimen that lasts two hours every single day.
00:55:34 The Milky Way galaxy and the Andromeda galaxy are going to meet in 3.75 billion years.
00:55:41 They're moving toward each other at a breakneck speed.
00:55:44 When two galaxies collide, they'll form a huge elliptical galaxy.
00:55:48 I won't be around then.
00:55:51 Have you ever looked up at the night sky and tried to count all the stars?
00:55:55 Yeah, good luck.
00:55:56 Our galaxy, the Milky Way, has about 100 billion stars,
00:56:01 but other estimates put it at over 200 billion,
00:56:04 since calculating the exact amount is an almost impossible task, even for astronomers.
00:56:10 In the entire universe, there are at least a billion trillion stars.
00:56:14 That's one with 21 zeros after it.
00:56:17 For comparison, that means there are more stars in space
00:56:21 than there are grains of sand on all of the Earth's beaches.
00:56:25 At a distance of 640 light-years from the Sun,
00:56:32 scientists discovered planet WASP-76b, where it rains iron.
00:56:37 The planet is very close to its Sun and always turned to it in the same side.
00:56:42 The term is tidally locked.
00:56:44 The temperature on the sunny side is so high that metals melt and evaporate there.
00:56:49 The other half of the planet is cool enough so that metals condense again and fall down as rain.
00:56:55 Speaking of tidal locks, our Moon is the same way.
00:56:58 There's no dark side to our satellite.
00:57:00 It's just always turned to us with one side.
00:57:03 When the Moon happens to be in between the Earth and the Sun,
00:57:07 what we call its dark side becomes brightly lit.
00:57:10 We just can't see it from our planet.
00:57:12 Figures.
00:57:13 A recent study claims that the Moon has a tail,
00:57:16 and every month it wraps around our planet like a scarf.
00:57:20 A slender tail made up of millions of atoms of sodium follows Earth's natural satellite,
00:57:26 and our planet regularly travels directly through it.
00:57:29 Meteor strikes blast these sodium atoms out of the Moon's surface and further into space.
00:57:35 You won't believe it, but the Moon seems to be shrinking.
00:57:38 Earth's natural satellite is now 150 feet smaller than it used to be hundreds of billions of years ago.
00:57:45 The reason for this phenomenon might be the cooling of the Moon's insides.
00:57:50 It could also explain the quakes shaking the surface of our planet's natural satellite.
00:57:55 Astronomers have recently found out that Mars is seismically active.
00:57:59 Mars quakes occur there on a regular basis.
00:58:02 For several days every month, the Moon remains between the Sun and our planet.
00:58:07 That's when Earth's gravity picks up that sodium tail.
00:58:10 Our planet drags it into a long stripe that wraps around its atmosphere.
00:58:15 This lunar tail is totally harmless.
00:58:18 It's also invisible to the human eye, 50 times dimmer than what you can perceive.
00:58:23 But on those rare days, high-powered telescopes can spot its faint yellowish glow in the sky.
00:58:29 The tail looks like a gleaming spot that's 5 times the Moon's full diameter.
00:58:35 Turns out there are plenty of planets in the Universe, and even in the Milky Way galaxy,
00:58:39 that have liquid or frozen water on them.
00:58:42 The closest one is within our Solar System.
00:58:44 It's Europa, one of Jupiter's moons.
00:58:47 Scientists are almost sure that underneath its frozen surface, there's an actual ocean of water.
00:58:53 But it's too soon to be hyped about possible life on such planets.
00:58:57 Liquid water is only one of many things that have to come together for life to appear on a planet.
00:59:03 A star in the galaxy GSN 069 is likely to turn into a planet the size of Jupiter in the next trillion years.
00:59:11 It might happen because of the star's regular encounters with a black hole.
00:59:16 First, astronomers noticed unusual X-ray bursts that were strangely bright.
00:59:21 They went off every 9 hours.
00:59:23 After studying this phenomenon for some time,
00:59:26 the scientists realized it was a star moving in a unique orbit around a black hole.
00:59:31 The dazzling flashes?
00:59:33 It was the material getting slurped off the star's surface by the black hole.
00:59:37 It turned out that over millions of years,
00:59:40 the black hole had already transformed the red giant into a white dwarf.
00:59:44 And the process isn't going to stop whatsoever.
00:59:47 Astronomers have found some traces of phosphine in the atmosphere of Venus.
00:59:52 On our planet, this gas, colorless and flammable, is often found where microbes live.
00:59:57 No wonder a new theory suggests that there might be life on Venus.
01:00:01 But even if there was some life on the "evening star", it could have only appeared in its atmosphere.
01:00:07 Probably no living organism would be able to survive the planet's extreme environment.
01:00:13 Venus's surface is extremely dry.
01:00:16 There's no liquid water on the planet.
01:00:18 And the pressure there is 90 times greater than that on Earth's surface.
01:00:22 The temperatures often rise higher than 900 degrees.
01:00:25 That's hot enough to melt some metals.
01:00:28 As for vacations there, I'll pass.
01:00:30 In fact, there's a place millions of light-years away
01:00:34 where there's a whole floating space cloud made entirely of water.
01:00:38 There's so much of it that we could fill all our oceans 140 trillion times over.
01:00:43 Slightly more than what we need.
01:00:45 Water on Earth is actually a puzzle shrouded in mystery and covered with riddles.
01:00:50 The most popular theory is that it was brought to our planet by icy comets and asteroids
01:00:55 that left behind not only mighty craters, but the liquid substance thanks to which we can now thrive.
01:01:01 But in space, there's a whole lot of organic matter.
01:01:05 And under specific conditions, it could yield so much water
01:01:09 it would be enough to fill our oceans thousands of times over.
01:01:12 Researchers conducted an experiment in which they heated this organic matter
01:01:17 and obtained clear water and oil.
01:01:19 If this is confirmed in future studies, it could mean that even oil appeared on Earth
01:01:24 not only thanks to fossilized remains of living beings, but came from outer space as well.
01:01:30 And yet, there might just be about 6 billion Earth-like planets in the Milky Way galaxy alone.
01:01:36 The latest data has shown that every fifth Sun-like star can have at least one planet in its habitable zone.
01:01:43 And not just any planet, mind you.
01:01:45 It has a rocky core and surface, and it's of comparable size to the Earth.
01:01:49 Being inside the habitable zone of its star,
01:01:52 such a planet would have high chances of becoming home to living creatures, microbes at least.
01:01:58 And if there are billions of these planets in our galaxy,
01:02:01 you could safely say that at least one of them is not only habitable, but inhabited already.
01:02:08 And now, multiply this by the number of galaxies in the universe,
01:02:12 also considering that many of them are much bigger than the Milky Way.
01:02:16 This gives us billions upon billions of Sun-like stars and Earth-like planets,
01:02:21 and some of them are surely more like ours than others.
01:02:24 And get this, we might be able to walk upright because of supernova explosions.
01:02:29 About 2.5 million years ago, a supernova sent cosmic rays to our planet.
01:02:34 They triggered a series of electrical storms in the Earth's atmosphere, which turned into thunderstorms.
01:02:40 Those, in turn, caused wildfires in Northeast Africa, where our earlier ancestors lived.
01:02:46 Fires turned the forest area into a savanna,
01:02:49 the atmospheric pressure changed, and our ancestors had to stand on two legs to survive.
01:02:54 The biggest explosion since the Big Bang was registered in 2019.
01:02:58 This happened in the Ophiuchus Cluster, which unites thousands of galaxies.
01:03:03 According to scientists, the blast was equal to 20 billion billion (that's 18 zeros)
01:03:08 megaton explosions happening once a millisecond for 240 million years.
01:03:13 I'll have to trust that, my math is not that good.
01:03:16 In 2019, NASA's InSight lander, whose goal was to study the interior of Mars,
01:03:22 registered the first Marsquake ever.
01:03:25 These quakes were coming fast, about two per day.
01:03:28 Most of them were tiny, you wouldn't even feel them if they happened on our planet.
01:03:32 So far, more than 300 Marsquakes have been detected.
01:03:36 Those are the first quakes on any space body other than Earth and the Moon.
01:03:40 Another mysterious phenomenon discovered by the mission was bizarre magnetic pulses.
01:03:45 They occurred every midnight around the lander.
01:03:48 It's still unclear what those pulses were.
01:03:51 Maybe after midnight, they're going to let it all hang out, or something.
01:03:55 Pluto's atmosphere rises much higher above the surface of the dwarf planet than, let's say, Earth's.
01:04:01 It also has more than 20 layers, all of them freezing cold and extremely condensed.
01:04:06 Remember the asteroid that wiped out the dinosaurs on Earth?
01:04:09 Hey, I wasn't around then. But who could forget?
01:04:12 There might have been another space show that ended badly for at least 75% of all life on our planet in the past.
01:04:19 Roughly 360 million years ago, a supernova explosion occurred about 65 light-years away from us,
01:04:26 and the cosmic rays sent by it swept away the ozone layer of our pretty blue ball.
01:04:32 Wow, tough neighborhood.
01:04:34 Our Sun. Scenario 1.
01:04:39 Something strange just happened now!
01:04:41 Every TV channel, the news, they're all talking about a black hole that came closer to us,
01:04:47 on the spot where our Sun used to be.
01:04:50 You can even see an accretion disk, and the background of the sky looks kind of distorted,
01:04:55 which means it got really close.
01:04:58 Normally, black holes are so far away that we can't see them with the unaided eye.
01:05:03 You can't even see them with a telescope directly.
01:05:06 What's it doing here so close? And where's the Sun?
01:05:09 Did the black hole swallow it?
01:05:11 The Sun used to be in the center of our solar system, far enough not to burn us,
01:05:16 but still close enough to give us light, warmth, and beautiful scenes
01:05:20 when it rises in the east and goes to rest in the west.
01:05:23 Hey, this one even rhymes.
01:05:25 Well, it gave us life.
01:05:27 The most massive body in our solar system contains 99.8% of its total mass.
01:05:33 It's so wide, you could fit more than a million Earths inside of the Sun.
01:05:37 Maybe our Sun turned into a black hole, but it's way too early for that to happen.
01:05:43 I mean, that's how they form.
01:05:45 When enormous stars come to the end of their life cycle and explode, which is called a supernova,
01:05:50 they end up collapsing on themselves, becoming very small.
01:05:54 It's a tiny size and a huge mass.
01:05:57 That's what makes black holes' gravity so strong,
01:06:00 and even light that comes too close can't escape.
01:06:03 And all the stars in the universe are shrinking and will disappear at some moment.
01:06:08 Our Sun loses 4 million tons of mass every second,
01:06:12 and eventually the only energy left in the universe will be generated by black holes.
01:06:17 A black hole is surrounded by dust, gas, and radiation.
01:06:21 The radiation is very dangerous, so we hope our planet won't come near it.
01:06:26 Our solar system doesn't have light anymore.
01:06:29 No light and no heat either.
01:06:31 So even Mercury and Venus will probably get covered in ice pretty soon, not to mention Earth.
01:06:37 Do I need to say nothing will survive this new ice age?
01:06:41 The only salvation might come from the accretion disk that spins so fast it generates heat,
01:06:46 but that's too many chances to take.
01:06:49 Still, at least if the black hole has the same exact mass as the Sun before it,
01:06:53 all the planets will remain in the same orbits, Earth included.
01:06:57 But if it has a mass bigger than our Sun, which is something our scientists are currently trying to figure out,
01:07:03 then bye-bye, solar system. It was nice knowing you.
01:07:07 Scenario 2.
01:07:09 Oh no, what's happening?
01:07:11 It was supposed to be a nice sunny day, but now you see darkness descending so abruptly.
01:07:16 How come it's night, yet the clock says it's 2 p.m.?
01:07:20 And the Moon looks different.
01:07:23 The TV reports say our Sun is gone, and due to some mysterious events,
01:07:28 the Moon is not orbiting the Earth anymore.
01:07:31 It's in the center of our solar system now.
01:07:34 We don't have much time left.
01:07:36 Since the Sun is not in the center of our solar system,
01:07:38 we now have 8 minutes and 20 seconds to become aware of it.
01:07:42 It may take millions of years for the Sun's energy to travel from its core to the surface,
01:07:46 but 8 minutes and 20 seconds is exactly how long it takes for sunlight to reach Earth.
01:07:51 The light takes a journey across 93 million miles,
01:07:54 which is the distance that separates us from the Sun.
01:07:58 We are not in the habitable zone anymore.
01:08:00 The habitable zone is the distance from a star, in our case the Sun,
01:08:04 at which liquid water could exist on the surface of a planet.
01:08:07 Now that the Sun's gone, its light won't reach us anymore,
01:08:11 and our planet will gradually become a frozen, lifeless rock.
01:08:15 Who knows if we'll have enough time to come up with some technologies
01:08:18 that would provide us with the solar energy we need to sustain life on Earth.
01:08:22 If not, well, millions or billions of years later,
01:08:26 scientists from some other civilizations would explore it,
01:08:29 trying to find evidence if life ever even existed there.
01:08:32 It would be the same as we do with Mars and other planets in our solar system,
01:08:36 trying to figure out if they've always been lifeless,
01:08:39 or if there might be a sign that some organisms used to live there.
01:08:42 Something else, also vital for our life, travels at the speed of light.
01:08:47 Gravity. Without the Sun, for roughly 8 more minutes,
01:08:51 the planets would continue circling the empty center of our solar system,
01:08:55 until the clock ticks and they finally drift somewhere
01:08:58 into an unknown direction of outer space.
01:09:01 Our Moon doesn't have a strong enough gravity to keep us in place.
01:09:05 It can't shine so brightly to give us warmth and support life.
01:09:08 It's so far, we can barely see it now.
01:09:11 Without the Moon that peacefully travels close to our planet as it used to,
01:09:15 we can see tides are getting lower incredibly fast.
01:09:18 Oh, and it's becoming really windy.
01:09:21 Winds are so much stronger and faster now.
01:09:24 When things were normal, our planet sat at a 23.5° tilt,
01:09:29 which is the reason we had changing weather and seasons.
01:09:32 Now the tilt is so extreme, it's getting very cold very fast.
01:09:37 And our time is almost up.
01:09:39 People are screaming, everyone's in panic.
01:09:42 We still have maybe one minute left until we sink into eternal darkness.
01:09:46 Scenario #3.
01:09:48 We're not sure what exactly happened,
01:09:50 and how the life we carelessly lived yesterday came to an end.
01:09:54 No one could predict it, but it seems that, out of nowhere,
01:09:57 a giant neutron star took the spot where our Sun used to be.
01:10:01 It's not something we'd recognize on our own.
01:10:03 We just noticed something was different,
01:10:05 and the Sun kinda got smaller and weirder.
01:10:08 The rest we heard on the news.
01:10:10 And no one knows how it happened.
01:10:12 Maybe our Sun is somewhere behind the neutron star.
01:10:15 Or the star pushed it out of our solar system and into an unknown direction?
01:10:20 A neutron star is the densest space object we know about.
01:10:24 It has almost twice as much mass as our Sun,
01:10:27 but it's all squeezed into a star only 10 miles, 15 kilometers, across,
01:10:32 which is about the size of a city on Earth.
01:10:34 A neutron star forms when a huge star runs out of fuel.
01:10:38 It collapses in a big explosion.
01:10:41 Its very central region, the core, collapses,
01:10:44 which is why every electron, negatively charged particle,
01:10:47 and proton, positively charged particle,
01:10:50 crush together into a neutron,
01:10:52 which is either uncharged or neutrally charged.
01:10:55 We're in a very tricky situation now,
01:10:58 basically waiting for our end to come.
01:11:01 This neutron star has gravity 2 billion times stronger than the one Earth has.
01:11:05 This means our new Sun will pull all the planets in our solar system towards itself
01:11:11 and eventually destroy them.
01:11:13 It's already started.
01:11:15 For the first time that we know of,
01:11:17 the planets are leaving their stable orbits,
01:11:19 attracted by the powerful force of the neutron star.
01:11:22 It's becoming chaotic pretty fast.
01:11:25 And it won't stop there.
01:11:27 A neutron star rotates more than 700 times every second,
01:11:31 which is incredibly fast.
01:11:33 Our Sun rotates once every 27 days.
01:11:36 So, after it destroys all the planets, including us,
01:11:39 this star will continue whirling throughout the universe
01:11:42 at about one-fifth the speed of light.
01:11:44 Maybe it will slow down and fizzle out with time,
01:11:47 but maybe not.
01:11:49 After thousands of years,
01:11:51 many neutron stars begin to slow down and blow out.
01:11:54 But that doesn't always happen.
01:11:56 If it meets another star, it will orbit it
01:11:58 and start to feed off its atmosphere
01:12:00 until it collapses at some point
01:12:02 and turns into a giant black hole.
01:12:05 Eh, our Sun was going to burn out anyway.
01:12:09 Until the neutron star showed up,
01:12:13 the Sun was 4.6 billion years old,
01:12:15 which was about halfway through its lifespan.
01:12:18 It had already burned off about half of its hydrogen stores
01:12:21 and had enough supplies for another 5 billion years.
01:12:24 It was eventually supposed to end up the size of the Earth.
01:12:27 After running out of fuel, it would have simply collapsed.
01:12:30 It would have retained its enormous mass,
01:12:32 but its volume was going to be similar to that of our planet.
01:12:36 No Sun, no life.
01:12:39 So the result would have been basically the same.
01:12:41 But this way, it would have been a slow process.
01:12:44 Who knows if humans would even inhabit this solar system in those times.
01:12:48 But with neutron stars, things move towards the end pretty quickly,
01:12:51 and it's way more chaotic.
01:12:53 If the neutron star was going crazy
01:12:56 somewhere far away in another galaxy,
01:12:58 we'd only see it in the shape of a distant flashing light
01:13:01 that we call a pulsar.
01:13:03 But this way, boom!
01:13:06 Wow, the James Webb Telescope has been fully deployed!
01:13:11 If you're interested in astronomy or space,
01:13:13 you've got to be excited about the James Webb Space Telescope.
01:13:16 Here's why.
01:13:18 For starters, it's huge.
01:13:20 How huge?
01:13:21 The primary mirror of the JWST is over 21 feet wide.
01:13:25 The Hubble Space Telescope, the previous largest eye in space,
01:13:28 has a mirror of about 7 feet, 10.5 inches.
01:13:31 By comparison, if you placed the two telescopes side by side,
01:13:35 it'd be like putting a horse next to an elephant.
01:13:37 And elephants are enormous.
01:13:39 There's a perfect reason why the Webb,
01:13:41 as it's affectionately called, is massive.
01:13:44 It has to be huge, because it's not an optical telescope
01:13:47 in the traditional sense that most telescopes are.
01:13:50 The JWST is an infrared telescope.
01:13:53 It sees heat.
01:13:55 Infrared light has a longer wavelength than visible light,
01:13:59 so it needs a larger mirror to focus that light.
01:14:02 So what do we have here with the James Webb Space Telescope?
01:14:05 We have two never-before things going on.
01:14:09 We have incredible technology and incredible science missions.
01:14:13 Both the missions and the technology
01:14:15 are out-of-this-world cutting edge.
01:14:18 The Webb is a classic example of engineering
01:14:20 in the service of science.
01:14:22 Because of its greater light-gathering power,
01:14:24 the James Webb Space Telescope will be able to take images
01:14:27 of things that we were never able to see before,
01:14:30 but have always wanted to see.
01:14:32 Things like exoplanets and the first galaxies in the universe,
01:14:35 and stars and planets forming inside nebulae.
01:14:38 And you can bet that there'll be plenty of surprises, too.
01:14:42 The James Webb Space Telescope
01:14:44 has several technological tricks up its sleeve,
01:14:47 which promise to provide its greatest scientific discoveries.
01:14:50 The Webb has a coronagraph,
01:14:52 and a very special coronagraph at that.
01:14:55 The coronagraph is the tool
01:14:57 that will allow the first real pictures of exoplanets.
01:15:01 The coronagraph blocks out the bright pinpoint light of stars,
01:15:04 which we already know have planets orbiting around them.
01:15:07 Without the coronagraph, the starlight would make things
01:15:10 too bright to see these planets,
01:15:12 because planets are hundreds of thousands of times dimmer than the star.
01:15:16 But with the coronagraph blocking the starlight,
01:15:18 the exoplanets come into view.
01:15:21 And the JWST coronagraph can block the light
01:15:24 from up to a hundred stars at once.
01:15:26 We can expect a swarm of exoplanets.
01:15:29 This brings us to the next high-tech gadget
01:15:31 the JWST has up its sleeve,
01:15:33 a no-slit spectrograph.
01:15:36 Usually, an ordinary spectrograph will have a slit
01:15:39 to allow a sliver of light to enter and be diffracted.
01:15:42 Diffraction is the scattering of light
01:15:44 to reveal the spectrum of the light's component wavelengths.
01:15:48 But the James Webb Space Telescope's work is so sensitive
01:15:51 that a sliver of light would overwhelm the optics.
01:15:54 So a no-slit spectrograph was installed.
01:15:57 The starlight gathered from the big mirror
01:15:59 is sent into a fiber-optic cable
01:16:01 to send only a single spot of light into the spectroscope.
01:16:05 And that's where the grism takes over.
01:16:08 Sir Isaac Newton used a prism to discover the spectrum of sunlight.
01:16:12 Roy G. Biv, as you may recall.
01:16:15 But the Webb uses a grism.
01:16:17 That's a compound word, like smog, which is smoke and fog.
01:16:21 A grism is a graded prism.
01:16:24 That means it has itsy-bitsy, teeny-tiny grooves
01:16:27 that diffract the spot of light the big mirror sends down
01:16:30 the fiber-optic cable and into the spectrograph.
01:16:33 The science of reading a spectrum of light is called spectroscopy.
01:16:37 By analyzing the spectra of light from the exoplanets,
01:16:40 the JWST will determine what gases are in the planet's atmospheres,
01:16:45 as well as their density and even their temperature.
01:16:48 It's an incredible advance in our knowledge.
01:16:50 We'll be able to tell if a planet has oxygen or nitrogen or methane
01:16:55 and other gases that may or may not indicate that the planet is habitable.
01:16:59 Another Earth, perhaps?
01:17:01 Presently, the JWST is "parked" in its permanent location.
01:17:06 Unlike the Hubble Space Telescope, which orbits the Earth,
01:17:09 the James Webb Space Telescope orbits the Sun.
01:17:12 It orbits the Sun at one of the gravitational balance points
01:17:15 between the Earth-Sun system.
01:17:17 It just stays there without having to use much or any fuel to hold its position.
01:17:22 So, as the Earth orbits the Sun,
01:17:24 the James Webb remains "parked" at a spot that is also orbiting the Sun.
01:17:29 There are five gravitational balance points between the Earth and Sun.
01:17:33 They are called Lagrange points.
01:17:35 After their discoverer, Joseph-Louis Lagrange, in the 18th century.
01:17:40 The Webb is parked at L2, the second of the five Lagrange points,
01:17:44 which lies 932,000 miles out into space, way beyond the Moon.
01:17:49 All this to observe a spot of infrared light.
01:17:53 But first, the engineers must get, or acquire, that spot of light.
01:17:58 To get a spot of infrared light,
01:18:00 the 18 hexagonal mirrors had to be unfolded from their position
01:18:04 inside the Ariane rocket that sent the Webb into space.
01:18:07 Once the mirrors have unfolded,
01:18:09 their positions must be adjusted to microscopic-level accuracy
01:18:13 so that all 18 mirrors produce a single image.
01:18:16 Several tiny motors are attached to each mirror segment to make these adjustments.
01:18:20 These motors, which must be activated individually,
01:18:23 will gradually pull the honeycomb-like mirror segments into alignment.
01:18:27 It's a critical part of the mission, and takes months to complete.
01:18:31 To align the mirrors to produce a single spot of light,
01:18:34 the James Webb Space Telescope can't be jiggling around.
01:18:37 The telescope must be kept absolutely motionless,
01:18:40 and that requires two other cutting-edge technologies,
01:18:43 the sunshield and the cryo-cooler.
01:18:46 In space, direct sunlight is very hot, and shadow is very cold.
01:18:52 Therefore, the James Webb Space Telescope brought along its own high-tech sunshield.
01:18:57 It's huge, too, as big as a tennis court huge.
01:19:01 Comprised of five individual layers of Kapton film only a millimeter thick,
01:19:06 each layer of the sunshield has to be remotely deployed individually
01:19:10 using a system of eight motors and 139 actuators with thousands of parts.
01:19:15 The purpose of the sunshield is to help the JWST stay cold.
01:19:19 The colder, the better.
01:19:21 And colder is what the cryo-cooler is for.
01:19:24 Temperature can be measured three different ways.
01:19:27 In degrees Fahrenheit, where water freezes at 32 degrees and boils at 212.
01:19:32 In degrees Celsius, where water freezes at zero degrees and boils at 100 degrees.
01:19:37 But neither of these thermometers have a starting point.
01:19:40 So Lord Kelvin, in the 19th century, devised a third temperature scale,
01:19:45 the Kelvin scale, which starts at absolute zero, the coldest temperature possible.
01:19:50 The onboard cryo-cooler will cool the JWST to just 7 degrees Kelvin,
01:19:56 7 degrees above absolute zero.
01:19:59 At this temperature, virtually all heat from motors is removed,
01:20:03 and the telescope will be able to focus the light to a point without any noise,
01:20:07 basically any motion interfering with the quality of the image.
01:20:11 Finally, after all this incredible technology functions, remotely, as planned,
01:20:16 we are almost ready to observe the infrared images from the giant,
01:20:20 multi-segmented mirror of the James Webb Space Telescope.
01:20:23 Almost ready.
01:20:25 A telescope can collect all the light it wants, but in the end,
01:20:28 it must also be able to detect what it's collected.
01:20:32 If the light is not detected, it's not truly observed.
01:20:35 Enter the piece de resistance, the infrared detectors.
01:20:39 The Webb has 15 of them.
01:20:41 The specially fabricated semiconductor material produces a slight electrical charge
01:20:46 when struck by a photon of infrared light.
01:20:49 The Webb's infrared detectors can produce a million-pixel high-def image.
01:20:53 A few of the detectors can produce a 4 million-pixel image.
01:20:57 They must be durable enough to last 10 to 20 years without warping or corrupting,
01:21:02 all while working at 7 degrees above absolute zero.
01:21:06 In themselves, the infrared detectors on the JWST are an engineering marvel.
01:21:12 But what are they going to take pictures of?
01:21:14 Ah, the missions of the JWST.
01:21:17 Well, they're cutting-edge, too.
01:21:19 70 of the first 280 target observations are exoplanets.
01:21:23 Is there another Earth?
01:21:25 Which exoplanets seem habitable?
01:21:27 The Webb Telescope will provide detailed spectroscopic analysis
01:21:31 of the atmospheres of thousands of known exoplanets.
01:21:34 For the first time, we will see images of exoplanets as they appear in infrared light.
01:21:40 Cosmology, the study of the universe, is perhaps the primary mission for the Webb.
01:21:45 Galaxies receding away so fast that their light is stretched into the infrared
01:21:50 will be a prime target for observation.
01:21:52 Hundreds of hours of observations are necessary to collect the faint infrared light
01:21:57 from these first galaxies formed after the Big Bang.
01:22:00 The JWST will give us a picture of what the infant universe looked like.
01:22:05 Astronomers will learn new information about the dark energy
01:22:09 that is driving the expansion of the universe and what role, if any,
01:22:12 black holes play in the formation of galaxies.
01:22:15 Star formation in the Milky Way and nearby galaxies
01:22:19 is also part of the mission of the James Webb.
01:22:22 By imaging hundreds of solar systems forming around newborn stars,
01:22:26 astronomers will establish a definite history of solar system development.
01:22:30 Now fact will replace theory, and a big step forward will be taken in our understanding of space.
01:22:37 The James Webb Space Telescope is a bold endeavor
01:22:40 that will mark an epoch time in scientific history.
01:22:44 They say somewhere out there, there's a pen that can work in zero gravity,
01:22:49 at extreme temperatures, and even underwater.
01:22:52 They say this pen can write on almost any surface.
01:22:55 Or if you turn it upside down, or when your surroundings are heated up to 570 degrees Fahrenheit.
01:23:01 They say NASA spent millions, or probably billions of dollars,
01:23:05 and almost a decade to develop such a pen.
01:23:08 The problem with ballpoint pens in space is that they don't work in the conditions of weightlessness.
01:23:13 The ink can't flow to the ball normally since gravity doesn't affect it.
01:23:18 Instead, pressure is created in the ink reservoir, and pens start leaking.
01:23:23 Some time ago, NASA used pencils,
01:23:26 but wooden pencils were considered to be a fire hazard in most spaceships.
01:23:30 All because, at that time, the atmosphere inside them was 100% oxygen.
01:23:35 The need for a super pen was obvious.
01:23:38 But whatever the rumors claim, NASA did not create such a pen,
01:23:42 spending a fortune on the research.
01:23:44 Its development was sponsored by Paul C. Fisher of the Fisher Pen Company, based in Chicago.
01:23:49 He spent over $1 million and almost 10 years to make a pressurized ink cartridge.
01:23:55 It was supposed to allow space pens to function in zero gravity and other extreme conditions.
01:24:00 Eventually, they got a pen that could write at a temperature of -30 to 250 degrees Fahrenheit,
01:24:07 which is really impressive, isn't it?
01:24:09 The pen was patented in 1966, and one year later, after conducting several thorough tests,
01:24:15 NASA started to provide Apollo astronauts with such pens.
01:24:19 Interestingly, the rumors about NASA spending an insane amount of money on the development of space pens
01:24:25 have been circulating for decades.
01:24:27 They have been debunked many times, but they appear again and again.
01:24:32 Many sci-fi movies can make you believe that everything happening in space
01:24:36 is accompanied by some kind of a sound effect, which is a totally false misconception.
01:24:41 In space, no one will hear you scream.
01:24:44 You know why? There's no air in space.
01:24:47 It's an almost perfect vacuum.
01:24:49 And sound waves don't travel through a vacuum.
01:24:52 They can't reach your eardrums and make them vibrate, sending signals to your brain.
01:24:56 But it's a good thing, especially for astronauts on spacewalks.
01:25:00 If not for the quietness of space, they would be constantly overwhelmed by the noise of solar storms.
01:25:06 Here's another one.
01:25:08 All comets have beautiful long tails.
01:25:10 It's nothing but a popular misconception.
01:25:13 In reality, comets are very difficult space bodies to spot.
01:25:17 They usually spend large amounts of time far away from stars.
01:25:21 There, in the darkness of space, they remain rather inactive and completely frozen.
01:25:27 Comets only get tails once they come close to a star.
01:25:30 That's when they start warming up.
01:25:32 This process makes them form some kind of a cloudy atmosphere,
01:25:36 which is called a coma, and a distinctive tail.
01:25:39 The tail always points away from the star that influences the comet.
01:25:43 It happens because the tail gets blown in the opposite direction by solar radiation and solar winds.
01:25:49 That's why the tail can often be in front of the comet, not trailing after it.
01:25:54 Now let's look at a light year.
01:25:56 This very notion makes us believe we speak about time here.
01:26:00 But in reality, light years measure distance.
01:26:04 NASA's definition of a light year goes like this.
01:26:07 The total distance that a beam of light moving in a straight line travels in a year.
01:26:12 And since light moves at a speed of 186,000 miles per second,
01:26:17 a light year equals almost 6 trillion miles.
01:26:21 Hey, do the math!
01:26:23 Now people often believe that in space, you experience zero gravity.
01:26:27 Hence the weightlessness astronauts feel on the International Space Station.
01:26:32 But that's not exactly true.
01:26:34 Gravity is one of the most important forces that exist in the universe.
01:26:38 Thanks to it, the Moon can orbit Earth, and the Sun doesn't float away from our home Milky Way galaxy.
01:26:44 But the astronauts on the ISS experience not full-fledged, but microgravity, which means very small gravity.
01:26:52 The gravity on the space station is only 10% weaker than the gravity on Earth's surface.
01:26:57 But astronauts are constantly in free fall.
01:27:00 The spacecraft, the people inside, and all the objects aboard keep falling forward, not down,
01:27:06 but around our planet, following a specific orbit.
01:27:09 And since they're all falling together, the crew and the stuff inside seem to be floating.
01:27:15 That's why astronauts can move things as heavy as hundreds of pounds with their fingertips.
01:27:20 And even though microgravity is often called zero gravity, they're very different things.
01:27:26 Now it may seem as if the Sun is always on fire.
01:27:29 At least, that's what it looks like in pictures.
01:27:32 But in reality, our star is a giant ball of gas.
01:27:36 Hey, I can relate.
01:27:38 Nuclear reactions happening in its core at all times makes the Sun burn.
01:27:43 Every second, hundreds of millions of tons of hydrogen are converted into almost as much helium.
01:27:49 During this process, huge amounts of energy are released as gamma rays.
01:27:53 Then, these rays turn into light.
01:27:55 In other words, the Sun does emit blinding light and incredible heat.
01:28:00 But it's not actually on fire because no oxygen is involved in the process.
01:28:05 A human can explode if they get into open space without a spacesuit.
01:28:10 Well, contrary to popular belief, taking off a spacesuit during a spacewalk won't be as dramatic as it's often pictured in movies.
01:28:18 A person will lose consciousness due to a lack of oxygen after 15 seconds of being in outer space without protection.
01:28:25 Before it happens, the person should breathe out as much air as possible.
01:28:29 Otherwise, this oxygen will damage their lungs from the inside.
01:28:33 Then, without the protection of the spacesuit, which is like a mini spaceship, the pressure inside their body will drop.
01:28:40 This will cause even more serious troubles.
01:28:42 And even though this person definitely won't burst, they won't want to stay outside for too long.
01:28:48 Black holes are giant, scary, cosmic vacuum cleaners, they say.
01:28:52 But in reality, black holes are more like fly traps.
01:28:56 They don't look for things to munch on.
01:28:58 Instead, they sit out there quite passively.
01:29:01 Only when a star comes too close does a black hole spring into action.
01:29:06 Even so, only those space objects that cross a certain border get ripped apart.
01:29:11 If the Sun were suddenly replaced with a black hole, Earth's orbit wouldn't change.
01:29:16 At the same time, Earth's temperature would be different.
01:29:19 There would be no solar wind, and no magnetic storms created by the Sun would affect our planet.
01:29:24 And let's say the black hole that replaced the Sun had the same mass as our star.
01:29:29 Then, according to the law of physics, Earth would have to come very close to get pulled into this black hole.
01:29:35 Now, the dark side of the moon myth was debunked more than 50 years ago.
01:29:40 And still, not everyone knows that this dark side is simply part of the Earth's natural satellite that faces away from our planet.
01:29:48 By no means is it darker than any other region of the moon.
01:29:51 And sunlight falls equally on all sides of the satellite.
01:29:55 It only seems dark because we never see this side of the moon from Earth.
01:29:59 All because of the phenomenon known as tidal locking.
01:30:03 Over billions of years, let me say that again, billions of years,
01:30:07 the gravitational connection between our planet and its natural satellite has changed their orbits.
01:30:13 The speed at which they move has also become different.
01:30:16 And since Earth is way bigger than the moon, the satellite's rotation was gradually slowing down.
01:30:22 Until at one point, it reached the point of balance.
01:30:25 And now, it takes the moon the same time to make a full rotation around its axis and a fully orbit around Earth.
01:30:32 Now, you might have heard people referring to Venus as Earth's twin.
01:30:36 It's true that both these planets are of almost the same size.
01:30:40 They have similar mass and composition.
01:30:43 The surface gravity on Venus is 91% of that on Earth.
01:30:47 So, if your weight was 100 pounds on our planet, on Venus, you'd weigh 91 pounds.
01:30:52 And still, calling these planets twins is a step too far.
01:30:56 The atmosphere on Venus is 100 times thicker than that on Earth.
01:31:00 Plus, its surface temperatures are insanely high, up to 850 degrees Fahrenheit.
01:31:06 That's hot enough to melt lead or burn up your pizza.
01:31:09 Venus has no water oceans or any life forms.
01:31:12 It also rotates backward compared to all other planets of the Solar System, including Earth.
01:31:18 By the way, another myth claims that Mercury is the hottest planet in the Solar System.
01:31:23 After all, it's the closest planet to the Sun, but Venus is actually hotter.
01:31:28 Asteroids strike Earth much more often than people tend to believe.
01:31:32 But most of these collisions aren't history-changing extinction events.
01:31:36 Most of them go completely unnoticed.
01:31:39 Most asteroids that approach our planet are qualified as small near-Earth objects.
01:31:44 They usually burn up in Earth's atmosphere before they even have a chance to wipe out life off the surface of the planet.
01:31:51 Not that they're big enough to do that.
01:31:53 And still, around 40 to 80 tons of space debris fall on Earth every year.
01:31:59 Most of this debris is tiny asteroids, also called bolides.
01:32:03 They're usually no larger than 65 feet in diameter.
01:32:06 Um, that's small?
01:32:08 Yeah, says so right here.
01:32:09 Okay.
01:32:11 Space suits are made of many different materials, elements, and functioning mechanisms for them to protect you in the vacuum of space.
01:32:18 Good thing.
01:32:20 The freezing temperatures and lack of oxygen aren't suitable for any living being to float around without any sort of protection on.
01:32:27 Not to mention the burning sun rays and potential objects that can crash into you.
01:32:32 The technical term for a space suit is "extravehicular mobility units."
01:32:37 And they're extremely durable and expensive to make, with each suit costing up to $10.4 million to make.
01:32:44 Each space suit is custom-made, with each part and component created and manufactured by 80 different companies.
01:32:50 The size of each piece may vary, so it can either fit in the palm of your hand or be as large as 30 inches.
01:32:57 The suit has 18 separate items and 16 layers covering it.
01:33:01 Well, in reality, there are 14, but if the two internal layers are added, it will be 16 in total.
01:33:08 So there.
01:33:09 Space suits have evolved over the decades to be the design it is today.
01:33:13 A mini-spaceship in human form.
01:33:16 It's built to mimic the living conditions of Earth's atmosphere, so that the astronauts can't be exposed to space.
01:33:22 It has a system to support oxygen and expel carbon dioxide.
01:33:26 It's durable enough to protect the astronauts from solar radiation, harsh sunlight, and little micrometeoroids.
01:33:33 The conditions inside our atmosphere can be extremely tough, which is why it has internal temperature control for the bodies and a pressurized enclosure.
01:33:41 The temperatures outside the suit can be as hot as 250 degrees Fahrenheit, ouch, to minus 250 degrees.
01:33:49 It's designed to support life or anyone outside our atmosphere.
01:33:53 The main piece of the suit is a cooling garment made out of nylon, stretchy spandex fibers, and liquid tubes.
01:34:00 It's delicately designed to fit around 300 feet of tubes woven tightly together in clothing that occupies the whole body, except the head, feet, and hands.
01:34:09 It uses chilled water to flow through the many tubes near the skin to regulate the body temperature and cool it down while spacewalking.
01:34:17 Think of it like a fan in a laptop that's made to cool it down when it overheats.
01:34:22 The whole garment is attached to the life support system.
01:34:25 Now, the life support system is one of the most important pieces of the suit and requires meticulous effort to put together.
01:34:32 Everything in this compartment is important to keep the astronaut alive in space.
01:34:37 Any miscalculation can be devastating and even life-threatening.
01:34:41 It houses the pressurized oxygen tanks when they're filled and sealed tight.
01:34:46 The oxygen tank can provide up to seven hours of fresh air to breathe.
01:34:50 There's also a secondary tank that adds around 30 minutes of breathing time.
01:34:54 Astronauts can't afford to waste oxygen all the time while wearing the suit, so it's important that they strategically allocate those breaths.
01:35:02 There's also the carbon dioxide removal device, which includes a filter canister made of lithium hydroxide that's also attached to a tube.
01:35:10 That way, there won't be any toxic carbon dioxide circulating inside of the headpiece, and it will always purify the air inside.
01:35:18 Next to it is a ventilation fan to cool the astronaut when moving.
01:35:22 Wearing a heavy suit isn't easy and requires a lot of physical effort to move.
01:35:27 Even though gravity is weaker up there, you still have to move your arms and legs, which can be tiresome over time.
01:35:33 There's also a source of electrical power and a two-way radio to communicate with the base.
01:35:38 And just in case something happens, a warning system is installed to warn the astronaut of failures in the system.
01:35:45 Uh-oh.
01:35:46 Finally, there's the water cooling equipment to keep the body cool and regulated.
01:35:50 After the life support system is put together, it's attached to the hard upper torso part.
01:35:56 The helmet on spacesuits, built for spacewalks, serves as a pressure bubble and is made of strong plastic to keep the pressure of the suit contained.
01:36:04 There's a neck ring to keep it airlocked in place and a ventilation system to provide oxygen to the astronaut.
01:36:10 And there's also a connection to a backup oxygen tank, just in case.
01:36:15 While the astronauts are working in space, they might crave a little bit of water or something.
01:36:20 Good thing there's a built-in straw for them to drink from.
01:36:23 And also, while working in open space, there's that annoying sun that shines into your eyes.
01:36:29 A visor is installed to protect the astronaut from the sun that's made of a gold coating.
01:36:34 And what's a spacesuit helmet without a camera to record everything?
01:36:38 Since the two-way radio is connected to the life support system, the headphones and microphone are placed in the chin strap, where the astronaut can communicate with the base.
01:36:47 Space can be dark at times.
01:36:49 Yeah, most of the time.
01:36:50 So, there's an inbuilt light bar used when operating on close-up objects.
01:36:55 Continuing our space fashion show gala, over at the lower torso unit, we have the pants and boots area.
01:37:02 There's also a knee to ankle and waist connection, comprising of a pressure bladder and a specially coated nylon.
01:37:09 Most of it is made out of different elements and materials to keep it usable and durable in space missions.
01:37:15 As well as providing stylish evening wear for that astronaut who goes out at night.
01:37:20 You can adjust the size of the rings of the thigh and leg sections whenever you want.
01:37:25 This is good when the astronaut is walking and needs to feel relaxed at certain times.
01:37:30 The astronaut also wears thermal socks under the hiking style boots, which have a heat retention system built in, to keep those tootsies warm and cozy.
01:37:39 The upper torso is hard, yet lightweight.
01:37:42 It's made out of metal and fiberglass, connecting the inside of the suit to the life support system.
01:37:48 It resembles a t-shirt, but attaches to the arm assembly, which stretches to the arms up over the wrist.
01:37:54 There's also a special connection to the helmet ring piece.
01:37:58 Over here, you can find water reservoir tanks, oxygen cans, and much other technical stuff needed for outer space.
01:38:05 The newer spacesuits have a hatch in the back for the astronauts to climb in and enter the suit.
01:38:10 How stylish!
01:38:12 A control module in the chest area allows the astronaut to check up on the external conditions and monitor the fluids and electricity.
01:38:20 The gloves are sturdy enough to protect the astronauts when touching and picking up objects while working outside the space station.
01:38:27 They're built so well that they can move each finger with ease.
01:38:31 They're the part of the body that gets cold fast in space, so the gloves have a heater system to keep them warm.
01:38:37 The process of creating a spacesuit requires so many steps and details, so it's not like sewing together a sweater.
01:38:44 It starts with a design integration, and then modeling.
01:38:47 That way, they can see what it looks like without gathering the materials to build it.
01:38:51 And once the design is confirmed, they begin gathering all the materials, which can take some time.
01:38:57 And when everything is gathered, they begin the fabrication and building, which can also take time.
01:39:03 A total of 7 different parts will be created and shipped to NASA for assembly.
01:39:07 When an astronaut goes outside the International Space Station, they must have a safety strap attached to them that connects to the station.
01:39:15 That way, they won't float away while doing some maintenance work.
01:39:19 The longest spacewalk lasted a total of 8 hours and 56 minutes.
01:39:23 And the suits have come a long way.
01:39:25 During the Apollo 11 mission, Neil Armstrong couldn't walk on the Moon properly, even though, technically, he was the first to walk on the Moon.
01:39:33 He actually did some bunny hops.
01:39:35 But with the newer innovations and technologies, astronauts can walk and turn their hips in space.
01:39:41 NASA plans on going back to the Moon by 2024 and is preparing two new spacesuits with better technology and dexterity.
01:39:49 It's called the Z-Move, and it's based on the current design of what astronauts wear on the International Space Station.
01:39:55 But the new designs and features will allow humans to live and work on the Moon.
01:40:00 A demonstration showed how flexible it is compared to the previous ones.
01:40:04 You can twist and bend at the waist.
01:40:06 The legwear section is better for walking on the Moon's surface.
01:40:10 Minor changes include no zippers or cables to keep out the dust.
01:40:14 You may think the Earth is pretty big, but the Sun makes up almost 99.9% of the mass of the whole solar system.
01:40:22 The rest of the mass is made up by the planets and their satellites, asteroids, comets, gas, and dust.
01:40:29 It's around 93 million miles away from our planet, but it keeps us warm every day.
01:40:35 Its temperature is about 10,000 degrees Fahrenheit, but the space surrounding it is still cold as ice.
01:40:42 To understand this, we need to distinguish between heat and temperature.
01:40:46 Heat is the energy inside some object.
01:40:49 Temperature is something that tells us if that object is hot or cold.
01:40:54 When the heat is transferred to that object, it makes its temperature go up.
01:40:58 When the object is losing heat, the temperature goes down.
01:41:02 Heat can be transferred in three different ways.
01:41:05 The Sun does it through radiation.
01:41:07 That means it's releasing heat in the form of light.
01:41:10 Your body radiates heat, too, as infrared waves.
01:41:14 That's why thermal imaging cameras will detect that you're in the room even at night.
01:41:19 The hotter the object, the more heat it will radiate.
01:41:22 The temperature only affects matter.
01:41:24 Since space is mostly a vacuum, it doesn't have enough particles for heat to transfer in any other way than through radiation.
01:41:32 When the heat from the Sun gets to an object, the atoms start absorbing energy.
01:41:37 But the heat can't transfer since there is no matter in space.
01:41:41 Those rare atoms and molecules in space will absorb the heat.
01:41:46 And they'll simply stay that way, while the cold vacuum will stay cold.
01:41:50 There's a lot of matter inside Earth's atmosphere, so the energy of the Sun can transfer easily.
01:41:56 But if you put an object outside of the Earth's atmosphere in direct sunlight,
01:42:00 it would end up heated to 250 degrees Fahrenheit because it's matter made of atoms and molecules.
01:42:08 The temperature of the vacuum is -454 degrees Fahrenheit.
01:42:13 That means, depending on where you are, space can either burn or freeze you.
01:42:18 The Sun isn't actually yellow. It emits light over a wide range of wavelengths.
01:42:24 We can tell both its temperature and color by the peak in its spectrum.
01:42:28 For instance, cooler stars will appear red, and hotter stars will be blue with yellow, orange, and white stars in between.
01:42:37 When it comes to the Sun, the spectrum peaks at a wavelength we'd usually call green.
01:42:42 But our eye perceives it differently.
01:42:44 So, the shade of green in combination with other wavelengths from the spectrum is going to look white to the human eye.
01:42:52 We generally see the Sun as yellow because our atmosphere scatters blue light more efficiently than the red one.
01:42:59 During sunrise and sunset, there's more red light in the spectrum of the Sun, which gives us amazing sceneries.
01:43:06 Sunspots are part of the Sun's visible surface that are on average way cooler than the Sun itself.
01:43:13 They overlap with parts that have an increased magnetic field.
01:43:17 These parts don't allow the release of heat to the Sun's visible surface.
01:43:21 That way, the rest of the Sun's surface is three times brighter than those sunspots.
01:43:27 That contrast makes them appear almost black.
01:43:30 If we could take a sunspot apart from the Sun and place it somewhere in the night sky, it would be different, as bright as the Moon when we see it from the Earth.
01:43:39 All the planets in our solar system spin in the same direction because they were formed from one protoplanetary cloud, except for Uranus and Venus.
01:43:48 They have probably had some strong impact on them that made them spin in the opposite direction.
01:43:54 But it's different with galaxies.
01:43:56 They don't usually form the same cloud of dust and particles.
01:44:00 Also, they're not randomly distributed across space.
01:44:04 They come in filaments, dense, slender strands of dark matter and galaxies, with voids in between.
01:44:11 Proto-galaxies are linked by gravitational forces in small areas of space.
01:44:16 This is probably because of the distribution of dark matter throughout the universe.
01:44:21 The matter in the filaments moves in a corkscrew motion and goes towards the densest area.
01:44:27 So, there might be a common direction galaxies tend to spin, but it's mostly random.
01:44:33 There's a possibility we'll see a lunar elevator one day.
01:44:37 Yep, a cable anchored to the surface of the Moon.
01:44:40 It would stretch 250,000 miles.
01:44:43 We wouldn't be able to directly attach it to our planet because both Earth and the Moon are moving.
01:44:49 But we could keep it terminated high in our planet's orbit.
01:44:54 Some researchers believe we could build such an elevator for a few billion dollars.
01:44:59 The Moon has resources we could definitely use.
01:45:02 A rare form of helium found there could be of use in fusion power stations on our planet.
01:45:08 Also, we could take some other rare elements and use them in smartphones and the rest of electronics.
01:45:15 So, after around 53 trips up and down, the elevator could pay for itself.
01:45:21 The cable would be as thick as a pencil, but its weight would be around 40 tons.
01:45:26 It could even be made of materials we already have here on Earth, with no need to invent something.
01:45:32 There could even be a combination of two elevators.
01:45:36 A spacecraft would winch up an elevator from the surface of our planet to a space station.
01:45:42 Then it would be flung towards the Moon.
01:45:44 There would be another elevator to finally lower it down to the surface of the Moon.
01:45:50 Planets in our solar system have predictable and stable orbits.
01:45:54 But gas giant collisions could have happened at an early stage when a planetary system was still forming.
01:46:01 In case of a head-on collision, two gas giants would merge.
01:46:05 They wouldn't end up losing their mass, the materials in their gaseous envelopes, or the ones in their solid cores.
01:46:12 Such a collision at a higher speed would cause the loss of the major part of the envelope gas.
01:46:17 And very high speeds? Boom! Both planets are gone.
01:46:22 It's different if it's not a head-on collision.
01:46:24 If two cores manage to completely avoid each other, gas giants won't merge, but they'll lose some of the mass.
01:46:31 Gas giants might even change their shape due to such collisions.
01:46:35 Astronomers found out there's a galaxy extremely far away from us that looks similar to our Milky Way.
01:46:42 We now see it as it was when the universe was only 1.4 billion years old.
01:46:48 And now it's 13.8 billion years old.
01:46:51 It took over 12 billion years for the light to come from this faraway galaxy and reach our planet.
01:46:58 This galaxy is peaceful, stable, and surprisingly non-chaotic, unlike all other galaxies that were quite turbulent in their early stages.
01:47:08 To leave the Milky Way, we'd have to travel around 25,000 light-years away from the center of the galaxy, or 500 light-years vertically.
01:47:17 Our galaxy is a disk of stars that spreads around 100,000 light-years across and is 1,000 light-years thick.
01:47:25 The Sun, its central star, is located halfway from the center of the galaxy and close to the middle of the disk in the vertical direction.
01:47:34 We'd have to go further than its edge to get away from the halo that surrounds the Milky Way, old stars, diffuse gas, and globular clusters.
01:47:44 If you wanted to go even further to see the Milky Way in all its glory, you'd have to travel 48,000 light-years vertically.
01:47:52 At this moment, we don't even have a telescope we can send there.
01:47:56 There are central stars that eat planets.
01:47:59 Our solar system is stable, unlike many other planetary systems, so we don't have to be afraid the Earth or some other planet will change its orbit and go towards the Sun.
01:48:09 But at least a quarter of other planetary systems with orbiting stars similar to the Sun have a pretty chaotic past.
01:48:16 In some of them, there are planets that used to move around, and their unpredictable migrations have disrupted the paths of some other planets or even pushed them outside of their orbit.
01:48:27 That means some planets probably have fallen into the central star.
01:48:31 When that happens, the planet gets dissolved in the outer layer of the star, which means it gets eaten.
01:48:38 Picture this. You're an astronaut hurtling through the cosmos in your state-of-the-art spaceship.
01:48:45 But suddenly, you notice that you're running out of fuel.
01:48:48 What are you going to do, trapped in the middle of space?
01:48:51 It's hardly like there's a floating gas station.
01:48:54 The good news is that you're not going to get completely stuck.
01:48:58 A spaceship will never actually stop after running out of fuel, all because there's basically no atmosphere in space.
01:49:05 That's where the popular phrase "in space, no one can hear you scream" comes from.
01:49:10 Sound travels through the vibration of teeny tiny atoms and molecules.
01:49:14 In space, where there is no air, there's simply no way for sound to travel.
01:49:19 It's the same for our spaceship.
01:49:21 Because there's no air, there's also a complete lack of air resistance.
01:49:25 Those tiny particles that do exist in space are way too small to reduce the spacecraft's momentum or drag it back.
01:49:32 Because of this, most spacecraft actually turn their engines off for the biggest part of their journey.
01:49:38 So, don't believe those movies that show spaceships with their engines on all the time.
01:49:43 That's completely inaccurate.
01:49:45 Unlike vessels in the water, a ship in space doesn't need constant thrust to keep moving forward.
01:49:51 Usually, its engine is only fired up for short periods of time.
01:49:55 This is not only practical, but also saves money.
01:49:58 Fuel is really expensive to transport into space as it's heavy.
01:50:02 That's why space probes try to use as little fuel as possible.
01:50:06 They need it when they set off from Earth, and then again when they re-enter the atmosphere.
01:50:11 It happens when they need to slow down upon their return.
01:50:14 While cars and trains have brakes, it's not that simple to bring a spaceship to a screeching halt.
01:50:19 The engines are needed to slow the ship down or bring it to a complete stop.
01:50:24 This involves strategically firing up impressive thrusters at the front.
01:50:28 It creates the needed drag and reduces the spaceship's speed.
01:50:32 But this process also requires super high levels of precision.
01:50:36 One wrong move and you're toast. Literally.
01:50:40 Hit the thrusters too fast and the spacecraft will set on fire as you re-enter Earth's atmosphere at thousands of miles per hour.
01:50:47 Traveling too slowly can also cause problems, because in this case, you might miss our planet's orbit completely and move way past Earth.
01:50:56 And most spacecraft don't have enough fuel to try for a second re-entry.
01:51:00 So traveling too slowly needs to be avoided at all costs.
01:51:04 But back to the issue at hand.
01:51:06 This basically means that any vehicle with an empty tank will continue traveling at the same speed across space until it eventually runs into something.
01:51:15 There's just no other way for it to stop.
01:51:18 Wait. Actually, maybe that's not good news.
01:51:21 If you get stranded, it's pretty unlikely that your buddies over there at NASA are going to organize a rescue mission.
01:51:27 This sounds kind of sad, but it does make sense.
01:51:31 By the time they set up a new team and find a ship to come and rescue you, you'll have already traveled so far into space it would take them years to reach you.
01:51:39 This would also cost a ridiculous amount of money.
01:51:42 NASA spends on average a whopping $152 million to launch a ship into space.
01:51:47 That's as much as buying six brand new top-of-the-range Lamborghinis.
01:51:51 Even crazier, it costs NASA about $49 billion to develop and launch the first space shuttle.
01:51:58 Unfortunately, once you've left Earth's orbit, it's near impossible that you'll make it back without fuel.
01:52:04 That's what actually happened to NASA's Dawn spacecraft back in 2018.
01:52:08 On a random day, the spaceship ran out of fuel. This left it completely stranded in the middle of space.
01:52:14 It stopped transmitting signals to Earth, bringing an end to an 11-year-long mission that set loads of space records.
01:52:21 The spacecraft could no longer generate electricity, as it had no fuel to move its solar panels to point them toward the sun.
01:52:28 And to this day, the spaceship is still floating somewhere in space in a derelict state.
01:52:33 Luckily, Dawn had no astronauts on board.
01:52:36 The spacecraft began to orbit the dwarf planet Ceres, which was the object it was originally investigating.
01:52:43 For context, in orbit is a curved path around a star, planet, or moon that an object gets stuck in.
01:52:49 But wait, NASA are experts in all things relating to spacecraft.
01:52:53 So how did they allow a ship to run out of fuel in the first place?
01:52:56 It's actually super difficult to accurately measure the amount of fuel you'll need in space.
01:53:01 On Earth, gravity keeps all the fuel at the bottom of the tank, and you can use a float sensor to measure how full the tank is.
01:53:09 But this is impossible in space due to a lack of gravity that normally weighs the fuel down.
01:53:14 Instead, a common approach is to add an air bladder into the fuel tank that's pressurized before launch to push the fuel into lines.
01:53:22 The more fuel is used, the more this bladder expands.
01:53:25 It takes up more space and keeps the fuel under the right amount of pressure.
01:53:29 This pressure is monitored. That's how they can tell how much fuel is left.
01:53:33 As you see, it's a lot more complicated than here on Earth.
01:53:37 But say there were astronauts aboard a spacecraft that had run out of fuel.
01:53:41 How long could they survive? Well, this depends on how much food and water is on board.
01:53:46 NASA usually calculates the extra amount of food astronauts need for their trip to avoid adding extra weight to the spacecraft.
01:53:53 But the good news is that this food can technically be rationed, and its consumption can be spread out.
01:53:58 That's because astronaut food comes in special packaging to stop it from going bad.
01:54:03 There are no refrigerators aboard spacecraft.
01:54:06 The food comes in clear, flexible pouches that can be snipped open with scissors.
01:54:10 All the food is pre-cooked and processed, so it doesn't need to be stored in a fridge.
01:54:15 The only exceptions are fresh fruit and vegetables.
01:54:18 These are the only things that need to be eaten quickly, as they will spoil.
01:54:22 Today, astronauts also work with nutritionists so they can pick out the foods that they like and will enjoy eating.
01:54:28 They can choose from a whole bunch of products, including mushroom soup, macaroni and cheese, chicken, beef, ham, nuts, and even yummy cookies.
01:54:37 Shrimp cocktail is apparently a new favorite among astronauts because of how spicy it tastes.
01:54:42 Flavored drinks also come in powdered form, just like the Kool-Aid or instant coffee packets you have sitting in your kitchen cupboard.
01:54:50 Interestingly, astronauts often report not feeling hungry in space, so it may be easier than you'd think to ration the food.
01:54:57 But even if you can make your food last, what about water?
01:55:01 Transporting anything into space costs a lot, and water is quite heavy, so it costs even more to transport.
01:55:08 For this reason, tanks of water can't be constantly shipped up to space.
01:55:12 Instead, astronauts have a really complex water system.
01:55:15 It squeezes every last drop of safe and available liquid out of the environment.
01:55:20 This involves recycling used water.
01:55:22 It means that our buddies in space drink water that's been filtered from old shower water, their breath, the spaceship's fuel cells, sweat, and so on.
01:55:31 But don't worry, such water is safe to drink, and it's actually even better than most drinking water that comes out of taps in the US.
01:55:38 The water on a spacecraft first goes through a bunch of filters, starting with one that removes particles and debris.
01:55:45 Then it passes through multi-filtration beds, containing clever substances that remove impurities.
01:55:51 The final stage gets rid of harmful compounds and destroys nasty bacteria and viruses.
01:55:56 There are also water reserves in case of emergency.
01:55:59 For example, the International Space Station keeps around 530 gallons of water in its reserves, just in case.
01:56:07 But what about the air supply?
01:56:09 The primary source of oxygen on spacecraft comes from something called water electrolysis.
01:56:14 This is an amazing system that uses electricity from the craft's solar panels to split water into hydrogen and oxygen gas.
01:56:22 But as we saw with NASA's Dawn, without electricity, it's pretty difficult to aim the solar panels at the sun, which means that the oxygen system would likely shut down.
01:56:31 There is some oxygen stored in a pressurized storage tank, though.
01:56:35 This is a backup supply designed for emergencies, so it's not all bad news.
01:56:41 So, you fall right into the heart of the black hole and prepare for a sad end.
01:56:49 Well, you don't have to.
01:56:51 Falling into a black hole won't necessarily destroy you or your spaceship.
01:56:56 You have to choose a bigger black hole to survive.
01:56:59 If you fall into a small black hole, its event horizon is too narrow, and the gravity increases every inch down.
01:57:07 So, if you extend your arm forward, the gravity on your fingers is much stronger than on your elbow.
01:57:13 This will make your hand lengthen, and you'll feel some discomfort.
01:57:17 Rather significant, to be honest.
01:57:19 Things change if you fall into a supermassive black hole, like the ones in the center of galaxies.
01:57:25 They can be millions of times heavier than our sun.
01:57:28 Their event horizon is wide, and gravity doesn't change as quickly.
01:57:33 So, the force you'll feel at your heels and at the top of your head will be about the same.
01:57:38 And you can go all the way to the heart of the black hole.
01:57:42 This myth is busted.
01:57:44 The next myth claims we can save the Earth from a giant asteroid with a big BAM.
01:57:50 The familiar plot is that a spaceship lands on the surface of an asteroid.
01:57:55 A team of astronauts quickly drills a hole in it, leaves a present there, and flies away.
01:58:01 Then, BAM!
01:58:03 As a result, the asteroid may break into several pieces and continue on its way to Earth.
01:58:08 Well, big chunks of the asteroid fall to our surface, causing a lot of damage.
01:58:13 So, our mission is failed.
01:58:16 Well, to save Earth, we need a really big BAM.
01:58:19 Not only outside the asteroid, but right above its surface.
01:58:23 When the BAM happens, the force of the blast pushes the asteroid slightly downward.
01:58:28 Even a slight change in trajectory would be enough to make the asteroid fly past the Earth in the future.
01:58:34 Done!
01:58:36 Oh, and if you made a big BAM on an asteroid, you'd never be able to hear its loud sound.
01:58:41 Yeah, we often hear the sound of spaceships and battle in space in the movies, but that's just a myth.
01:58:47 Sound is a wave that spreads because of the vibrations of molecules.
01:58:52 A person claps a few feet away from you.
01:58:55 The sound wave begins to push the first air molecule next to the clap,
01:58:59 then the third, fourth, and so on until the wave reaches your ear.
01:59:04 So, to spread sound, we need molecules like air or water.
01:59:08 In our atmosphere, sound waves spread out just fine, but space is a vacuum, so it's nothing here.
01:59:15 You can clap your hands loudly there, but there just won't be any molecules that can vibrate and carry that sound.
01:59:22 One more myth about asteroids.
01:59:24 We need to fly a little farther than Mars' orbit.
01:59:27 Whoa, we're in an asteroid belt, and we constantly have to dodge giant rocks and blocks of ice.
01:59:34 We got in some dense asteroid cloud.
01:59:37 Not true.
01:59:39 The fact is that space is huge, and the distances are incredible.
01:59:44 All the rocks and debris in the asteroid belt are only 4% of the weight of the Moon,
01:59:49 so there really aren't that many of them there.
01:59:53 To understand the size of the emptiness in space, look at the collision of two galaxies.
01:59:59 There are billions of stars in each of them.
02:00:02 If we mix them up, it's unlikely there will be any collisions even here.
02:00:07 Another myth is that there's zero gravity in our orbit.
02:00:11 Imagine you're in a huge box 10 miles up in the air.
02:00:15 Now we let go of the box, and it starts to fall.
02:00:18 You're falling simultaneously with the box at the same speed.
02:00:22 And now it's as if you feel zero gravity.
02:00:26 Well, the same thing happens in orbit.
02:00:29 The International Space Station is 250 miles above the Earth,
02:00:33 and it's falling continuously, though not on the surface of the planet, but around it in its orbit.
02:00:40 Its speed at this point is about 4.7 miles per second.
02:00:44 It could cross the United States from the West Coast to the East Coast in just 8 minutes.
02:00:49 So the astronauts there are experiencing the same thing.
02:00:53 They're just falling with the ISS at that speed.
02:00:57 Now let's look at the Moon. It always looks at us with one side.
02:01:01 This means the Moon has a dark side, and the Sun's rays never get there.
02:01:05 Well, that's a myth.
02:01:07 The whole point is that the Moon is gravitationally locked to the Earth.
02:01:11 There are days and nights there too.
02:01:14 It's just that this rotation is perfectly aligned with the rotation of the Earth.
02:01:19 So whenever you look at the Moon, you only see one side.
02:01:23 Although there are days when the Sun shines there too.
02:01:26 So it's not the dark side, it's the far side.
02:01:30 And we even have pictures of this place.
02:01:33 And there's one of the biggest craters in our entire Solar System, the South Pole-Aitken Basin.
02:01:39 It's as wide as two states of Texas.
02:01:42 One myth that turned out to be untrue is that people have never actually been on the Moon.
02:01:48 This is the original spacesuit of the first astronauts who were there.
02:01:52 Look at the sole of the shoe.
02:01:54 Some people claim there's no way they could've left footprints like this there.
02:01:58 Actually, they could.
02:02:00 On the Moon, the astronauts wore extra boots over their suits,
02:02:04 and their soles matched the footprints on the Moon perfectly.
02:02:08 The astronauts didn't grab them when they left the Moon.
02:02:11 They left a lot of stuff there too.
02:02:13 They even ripped out the armrests of the seats of the lunar module to reduce its weight.
02:02:18 Now, the total weight of human trash on the Moon is about 187 tons,
02:02:24 including several lunar rovers, spacecraft debris, rocket stages, and lunar probes.
02:02:30 That's like three Boeing 737s.
02:02:33 The next myth is about summer.
02:02:35 The hot season comes because the Earth approaches the closest distance to the Sun in a year.
02:02:41 The Sun warms our planet more, and we all have to go to the beach.
02:02:45 Well, not true.
02:02:47 Let's draw an axis through our planet.
02:02:50 It's slightly tilted on one side, and winter comes when our planet's axis is tilted away from the Sun.
02:02:57 But over time, the axis tilts toward the hot star.
02:03:01 Then its rays shine at such an angle that it gets warmer.
02:03:05 It's true, though, that the Earth happens to be at different distances from the Sun.
02:03:09 This is because our orbit is not a perfect circle, but slightly flattened, an ellipse.
02:03:15 Normally, we think of the distance to our star as about 93 million miles,
02:03:20 but that distance may be longer or shorter than 3 million miles,
02:03:24 depending on which point in our orbit we pass.
02:03:27 Another myth about the Sun is that it's yellow.
02:03:31 Well, let's send you into space for this one.
02:03:33 You look out the window and… it's white!
02:03:37 The Sun only appears yellow to us through the filter of our atmosphere.
02:03:41 The composition of the air and its thickness just distorts the light of the star.
02:03:46 But stars do come in different colors.
02:03:49 Cooler stars have bright orange and red colors.
02:03:52 These are usually very old stars, older than our Sun.
02:03:56 But young and very hot stars are bright blue.
02:03:59 The Sun is about in the middle of the spectrum.
02:04:02 You've also heard about how, if you take your spacesuit off in outer space, you'll blow up like a balloon?
02:04:09 Well, our bodies are designed to function at atmospheric pressure, like outside.
02:04:14 But space is a vacuum.
02:04:16 Imagine a huge metal barrel, and we sucked all the air out from there.
02:04:21 Add to that a temperature of -455°F, and you have space.
02:04:27 If you could get into those conditions, all the air pockets in our body, like our lungs, would start to expand.
02:04:34 So, you really could blow up like a balloon if it weren't for our elastic tissues.
02:04:39 They stretch and bend, so you keep your body size.
02:04:43 You'll have enough oxygen in your body to last about 20 seconds.
02:04:47 Then your brain will begin to starve, and soon you'll pass out.
02:04:51 So, you won't blow up, and you won't even freeze, because you'll be in a vacuum.
02:04:56 It doesn't conduct heat.
02:04:58 For example, water conducts heat very well, and you feel cold from it instantly.
02:05:03 But you feel better in the air of the same temperature.
02:05:06 If you're in the vacuum of space, the super low temperature won't be a problem for you.
02:05:12 Much worse is solar radiation.
02:05:14 On Earth, we have a shield against radiation in the form of the atmosphere.
02:05:19 It blocks the harmful rays.
02:05:21 In outer space, you would be defenseless.
02:05:24 Another myth is related to cell phones.
02:05:27 People think that when you dial your friend's number, your phone sends a signal into space.
02:05:32 There are a bunch of satellites out there that will pick up your signal and reflect it like a mirror right into your friend's home.
02:05:39 No, not true.
02:05:41 However, there are satellite phones in the world that work that way.
02:05:45 But when you make a cell phone call, your signal is transmitted through a system of cell towers from one to another until it gets to your friend's phone.
02:05:54 That's it for today!
02:05:56 So, hey, if you pacified your curiosity, then give the video a like and share it with your friends.
02:06:01 Or if you want more, just click on these videos and stay on the Bright Side!

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