For twenty years, NASA's Cassini spacecraft revealed the strange secrets of Saturn until it vaporized in its atmosphere in a blaze of glory; but today its legacy lives on, as fresh data from the probe helps scientists make brand-new discoveries.
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LearningTranscript
00:00for 13 years the Cassini spacecraft explored astounding worlds Saturn and its moons
00:11we discovered things we never imagined all of these strange bizarre landscapes geysers erupting
00:21out of moons we were so stunned by the images I mean people were just going around in shock
00:30but Cassini started running out of fuel scientists at NASA had to decide what to do next and the answer
00:45was actually pretty spectacular Cassini goes where no spacecraft has gone before
00:52a depth flight revealing the deepest secrets of Saturn
00:59out beyond Jupiter lies Saturn a planet circled by multiple moons and rings it's like a miniature solar
01:18system imagine having a mission with the power the instruments the capability to explore all aspects of the Saturn system
01:25that mission was Cassini
01:29that mission was Cassini
01:32that mission was Cassini
01:37it would become our eyes and ears in the Saturnian system for over 13 years
01:56but by September 2017 Cassini is almost out of fuel
02:04Cassini has been orbiting Saturn and studying the Saturn system for over a decade
02:10end the mission we're going to lose control soon
02:13so rather than let it just go derelict we headed into Saturn
02:17go out with a bang
02:19the Cassini team goes for broke
02:23they program the probe to head straight for the planet
02:27how cool is it to sort of sacrifice everything you've got to sort of learn your life
02:33your last bit of information and then crash and burn
02:36we are in the atmosphere
02:40as Cassini was careening toward its death
02:43it still had instruments that continued to work
02:45and as each instrument died
02:47there was still a set sending back data and information
02:50Cassini wasn't designed to plunge through Saturn's atmosphere
02:54no one knew how long it would last before burning up
03:09I remember sitting in a room with my colleagues on Cassini
03:12and watching that radio signal that sharp green peak
03:16that told us Cassini was still linked to the earth
03:19we could monitor the atmosphere as we flew into it
03:23and right up until the last it was sending back signs
03:26I was really impressed by how long Cassini lasted
03:29in the Saturn atmosphere
03:32I mean go NASA engineering
03:34as Cassini plummeted down at 77,000 miles an hour
03:39it was bombarded by gas molecules in Saturn's atmosphere
03:44friction started tearing Cassini apart
03:51as it struggled to maintain contact
03:56as the antenna turned away
04:01we actually saw a secondary little peak
04:03and we thought okay Cassini hang in there
04:05keep fighting
04:06and then just that green flat line
04:09just heard the signal from the spacecraft
04:15is gone
04:16and within the next 45 seconds
04:18so will be the spacecraft
04:20Cassini's heartbeat was gone
04:23and we knew the mission had ended
04:26it just vaporized in the Saturnian atmosphere
04:30and so it has become a part of Saturn itself
04:34Cassini's death plunge was the last of a series of daring dives
04:51prior to ending Cassini's mission by sending it into Saturn's atmosphere
04:55NASA's engineers and scientists came up with an idea
04:58let's do dives into the region between the tops of Saturn's clouds
05:03and the innermost area of Saturn's rings
05:06beginning in April of 2017
05:11Cassini ventured between Saturn and its rings 22 times
05:16scientists called it the grand finale
05:20on these dives Cassini got closer to Saturn's cloud tops
05:26than any spacecraft ever had before
05:28Saturn is an enormous ball of hydrogen and helium
05:35a gas giant
05:39fundamentally it's a really very different kind of planet
05:42than we're used to in our everyday lives
05:45Cassini snaps close-ups of the planet's gaseous surface
05:49the pictures reveal a turbulent and stormy world
05:53we think of some storms on earth as being particularly violent
05:57if you've ever been in a hurricane that's not a fun place to be
06:00but the storms on Saturn the wind patterns on Saturn
06:03can make that look like a mere breeze in comparison
06:06on Saturn one storm stands out
06:11its location is marked by a distinct shape
06:14one of the really weird things is that once the bands go around Saturn
06:19they're all circular until you get to the pole
06:22and then there's a hexagonal band up there
06:25no one expected that
06:28during its lifetime
06:30Cassini took multiple images of the hexagon
06:34whenever we posted an image of the hexagon
06:37the hits to the website went through the roof
06:40I think people thought it was so mysterious
06:43when I first saw this I was blown away
06:46I mean who could imagine having something this regular
06:49almost geometric on the atmosphere of a planet
06:51it's really just phenomenal
06:53in 2018 Cassini data reveals
06:57this hexagonal storm could be a towering structure
07:02hundreds of miles in height
07:04it's this gigantic structure
07:06it's many thousands of miles across
07:08and right in the center right at the pole
07:10is this sort of permanent vortex
07:12a permanent hurricane
07:13so it's kind of a creepy eye-like thing
07:16staring back at us
07:18each side of the hexagon
07:20is as wide as the earth
07:22it seems artificial
07:25how do you get a hexagon shaped storm
07:28or cloud structure on Saturn
07:30scientists think that Saturn's spin interacts with air currents
07:41to create this symmetrical shape
07:44but they don't know
07:46why it's lasted for decades
07:48that's the puzzle
07:51how can you get a six-sided jet stream that's stable
07:54for so long
07:56but while the hexagon shape is stable
08:00the color has altered
08:03over four years
08:05it changed from mostly blue to golden brown
08:08the transformation is linked to Saturn's seasons
08:18the seasons on Saturn are caused by the same thing on earth
08:21it's the tilt of the planet
08:23and so as Saturn is going around the sun
08:25and its north pole is tipping toward the sun
08:28you start to get more light up there
08:30this sunlight interacts with the atmosphere
08:34producing suspended particles called aerosols
08:39it actually looks a lot like smog
08:41it turns things more orange
08:43so over time the hexagon went from blue to orange
08:47the color change happened during one of Saturn's northern hemisphere summers
08:52but mysteriously the very center of the hexagon remained blue
08:58now this could have been for two reasons
09:00maybe the haze never formed in the eye
09:02because the eye was shielded from the sun
09:04and the sun is responsible for creating the brownish haze that we see on Saturn
09:09another reason is maybe the actual vortex is sucking the haze down
09:14maybe there's something like the eye of a hurricane
09:16there's haze that forms over it but it gets sucked down into the eye
09:20but the storms on Saturn aren't the only extraordinary thing about the weather
09:32when Cassini dives through the rings
09:35it discovers rain
09:37rain falling onto the planet from space
09:50April 2017
10:03Cassini embarked on its grand finale
10:06following a daring new path
10:09we decided to dive in between the rings and the planet
10:14to go to a place no spacecraft had ever flown before
10:18and make a unique set of measurements
10:21it was uncharted territory
10:25they didn't know exactly what they were going to find
10:27there could be stuff there that could have destroyed the Cassini spacecraft
10:31instead Cassini encountered something totally unexpected
10:37rain
10:41on Earth it rains quite a bit
10:51we're getting that rain from rain clouds
10:53which are basically just a few miles up
10:55on Saturn it also rains
10:58but it turns out it's raining onto the top of the upper atmosphere
11:01and that rain is coming from space
11:04in 2018
11:07Cassini data revealed the colossal weight of the downpour
11:11icy grained rain hit Saturn at a rate of several tons per second
11:22it's completely unlike anything we've ever seen
11:24suddenly we've discovered rain at Saturn
11:26but there aren't any rain clouds
11:28where is it coming from?
11:29the answer is Saturn's rings
11:38the first thing you think of when you hear the word Saturn
11:43is the rings
11:44they're the most dramatic and unique aspect of that planet
11:47from afar
11:51Saturn's rings look like just one whole structure
11:54but when you look up close
11:55it's actually a bunch of ice crystals and ice rocks
11:59that make Saturn's rings
12:03the size of the ring material ranges from dust grains
12:07to boulders
12:08to houses
12:16Saturn's rings are well above the atmosphere of Saturn
12:20they're way out in space
12:21and under normal circumstances
12:23those particles of ice making up the rings
12:25would just orbit Saturn forever
12:28but things are a little bit weird
12:34something is making these orbiting ice particles
12:37fall inward as a kind of cosmic hail
12:44material is dripping inwards from the rings
12:46and falling into the clouds of Saturn
12:49it's like a rain with no rain cloud
12:52the cosmic rain trickling in and falling down
12:56Cassini discovers the rain is a mix of different kinds of ice particles
13:03but doesn't reveal why they actually rain down
13:07then the researchers realized the ice grains were statically charged
13:14ultraviolet light from the sun for example
13:17can blow off an electron
13:19and that gives these particles a charge
13:21just like rubbing a balloon on your hair
13:23makes it stick to a wall because of the static charge
13:28well if you have particles that are like that
13:31they can be affected by magnetism
13:33and Saturn has a very strong magnetic field
13:36Earth's magnetic field springs from its spinning molten iron core
13:42although Saturn probably has a rocky center
13:47it's mostly a giant ball of hydrogen and helium
13:51but deep in its interior scientists think something
13:55much more exotic is going on
13:59we don't have enough data to know exactly what's going on in Saturn's interior
14:03but we do know the broad strokes
14:06within Saturn's interior
14:08extreme pressures and temperatures
14:10force hydrogen to stop acting like a gas
14:14turning it into spinning liquid metallic hydrogen
14:19you've got this band of electrons that can just wander freely through that fluid
14:23so in that way liquid hydrogen under extreme pressure can act like a metal
14:28the magnetic field generated by the spinning metallic hydrogen outer core
14:35pulls the ice particles from the rings
14:39these charged ice particles are then drawn in by Saturn's field
14:43they follow the magnetic field lines and rain down onto the atmosphere of Saturn
14:49Cassini had revealed several tons of material as raining down on Saturn every second
14:57but how much stuff is actually in the rings
15:00again Cassini provides the answer
15:04in the final days of Cassini we actually flew in between the planet Saturn and the rings
15:09and the gravity data was able to separate out
15:12how much mass is coming from the planet
15:14and how much is coming from the rings
15:16and the surprise was the rings are actually not very massive at all
15:20even though they cover an area as big as the moon's orbit around Earth
15:27Saturn's rings are a hundred thousand times less massive than our own small planet
15:33they're lighter than we thought there's not as much material there
15:40the mass of the rings is a valuable clue about their age
15:45a more massive ring can hold itself together for much longer than a less massive ring
15:52so if there's not a lot of stuff there it must be younger
15:59so how long have Saturn's rings been in place and what is keeping them there?
16:04it's something that I don't even think I could have imagined if I tried
16:08as Cassini orbited Saturn it revealed incredible insights into the planet's rings
16:35the photos that came from Cassini of the rings are unlike anything that I could ever imagine
16:50if I was an alien visiting our solar system I don't know what would stand out to me more
16:55the blue marble or Saturn and its amazing rings
16:58one of the biggest questions about the rings is how old are they?
17:04could something like that really have existed from the beginning of the solar system
17:08or is it relatively recent?
17:11Cassini provided an answer
17:16the rings could be as young as only a hundred million years old
17:19a couple of clues, the low mass and the fact that they're so bright and icy
17:23that it hasn't had time to get polluted from all the micrometeoroids
17:27and darkened over a long time like the age of the solar system
17:31so the amazing thing is that you know if you were on earth about the time of the dinosaurs
17:37there might have been a Saturn in the sky with no rings
17:40so if the rings didn't form at the same time as Saturn
17:48how did they form? and what's keeping them in place?
17:52to form the rings a hundred million years ago you need to find an object
18:03maybe a comet or a moon gets too close to Saturn
18:07Saturn's gravity tears it apart and forms the rings
18:10as the object is torn apart the pieces spread out around Saturn to form the rings
18:19they keep colliding breaking into smaller and smaller pieces
18:25like pebbles on a beach subsequent jostling and self collisions between each other
18:31will take the sharp edges off of them creating rounded particles
18:34from a distance Saturn's rings appear incredibly thin
18:42and almost perfectly flat
18:44but appearances can be deceptive
18:47one of our last results from Cassini as it took its final plunge into Saturn
18:54was as we flew past those rings
18:56we noticed that the rings were actually not a uniform density
19:01that's something that nobody had seen
19:03I mean you had to get really close to see that and it wasn't expected
19:07I'm a ring scientist and I just love seeing that detail
19:11and trying to figure out why do Saturn's rings look the way they do
19:17there are very intricate structures
19:19knife-edged little ringlets
19:21and like almost like the grooves in a record
19:25begs the question of course
19:26where do those structures come from?
19:34the clue is hidden within the rings
19:36there's not five rings
19:39there's not five hundred rings
19:41there's thousands of rings
19:43there's potentially millions of tiny little ringlets
19:47with small gaps between them
19:49and sometimes large gaps
19:51and Cassini saw that there are moons
19:54embedded inside the rings
20:01these moons and moonlets seem to be shaping the rings
20:05the rings
20:09when I think about the rings of Saturn
20:11I almost hear symphonies playing in my head
20:13it's all about this wonderful structure
20:15and these harmonies
20:16the balances between gravity
20:18so we use the word resonance
20:23Saturn's moons stir the ring particles
20:26with their gravitational pull
20:28creating waves
20:29there's a special place where the resonance exists
20:35imagine where the ring particles will go around twice
20:39for each single time the moon goes around
20:41it's like pushing someone on a swing
20:43if you push them at just the right rate
20:45they go higher and higher
20:47and these places are where the waves generated
20:49so there's this ballet
20:53this dance between the ring and the moons
20:55it is one of the most elegant things I've ever seen
21:06but the rings aren't just being shaped into waves by the moons
21:10they're being held in place by them
21:13through gravitational interactions
21:16these moons might be shaping the rings
21:19shepherding them
21:20keeping their flock
21:22in a nice tight orbit around the planet
21:29in 2017
21:30Cassini reveals
21:31there are more than one or two moons
21:34shepherding the rings
21:36a whole team of moons
21:38hold Saturn's outermost visible ring
21:41the A-ring in place
21:44one of the really cool things
21:46that Cassini discovered during its death dive
21:48was that there are seven moons of Saturn
21:50that are all working together
21:51to keep that ring system in configuration
21:54so it's like the magnificent seven
21:56holding this thing together
22:02of the seven magnificent moons
22:05the biggest is minus
22:07it's one-eighth the size of our moon
22:09the smallest
22:12the smallest
22:13pan
22:14is only twenty miles across
22:18acting in combination
22:19these moons
22:20hold all of Saturn's rings
22:22in check
22:25so it's
22:26these seven moons working together
22:27forming the ring system
22:28that we see today
22:29Cassini has truly opened our eyes to the wonder of Saturn's rings and many moons
22:44Saturn has
22:46Saturn has
22:47a lot of moons
22:48I mean a lot of moons
22:49and they're all really interesting and different
22:51coming up with an exact number is a little difficult
22:54because it almost changes every year as we discover new ones
22:59the latest count is over 60 moons
23:02each with a different character
23:04but one
23:05has a split
23:06personality
23:07and a very dark side
23:09dark side
23:10dark side
23:11may 2017
23:14Cassini was on its grand finale
23:18the probe snapped its last photo
23:23of a strange moon two million miles from Saturn
23:36eyapetus
23:40eyapetus was discovered hundreds of years ago
23:43miles from Saturn. Iapetus. Iapetus was discovered hundreds of years ago and
23:52right from the start it was recognized that one side of it was very bright and
23:57the other side was as dark as dark can be. This dark and light moon confused
24:05Italian astronomer Giovanni Cassini when he first spotted it in 1671. It's been
24:14puzzling scientists ever since. So we get there with Cassini and of course Iapetus
24:22was a very major target for us because we were interested to know what what was
24:28with this crazy two-toned moon. Cassini reveals that the answer lies even
24:38farther out from Saturn in the form of another moon. There's one pretty big but
24:45really dark moon Phoebe that's outside of Iapetus and is orbiting the opposite
24:51direction around Saturn. Phoebe orbits Saturn four times farther out than Iapetus.
24:57As it travels around the planet micrometeorite impacts on the moon's
25:03surface generate a cloud of dark dust. The dust from Phoebe actually creates a
25:09large ring. A ring of dark dusty material that's drifting inward stored Saturn going
25:16the opposite direction of Iapetus which is the perfect material for Iapetus to
25:21sweep up in its orbit to create one dark side.
25:27Iapetus has one dark side because it's tidally locked to Saturn. One side always faces the planet
25:39while another side drives forward through the dust. It's plowing through a bunch of dust that's sticking
25:50to the front side kind of like bugs on a windshield. Cassini discovered this dark
25:56dust makes the leading side warmer than the trailing bright side by 50 degrees Fahrenheit.
26:02When you have something that's dark like the dust on the leading edge of Iapetus
26:07that gets warmer it absorbs sunlight better and if it's warmer then things that can
26:12evaporate more easily like water for example tends to blow off the surface.
26:17The front side gets darker and warmer.
26:22Any visible ice turns to vapor and makes its way to the colder trailing side where it refreezes.
26:31So the white side gets whiter and the dark side gets darker. So you have the self-sustaining
26:41dark side and bright side and you wind up with this two-faced moon.
26:49Iapetus's two sides are strange.
26:52But Cassini discovers that they're not the weirdest thing about this moon.
27:01The weirdest thing is that it is a walnut.
27:09Iapetus has a mountain range that exactly circles its equator all the way around the moon.
27:14A mountain range higher than the Himalayas.
27:22These mountains are over 12 miles high.
27:30More than twice the altitude of Earth's highest peak, Mount Everest.
27:37It's crazy. It's this huge, crazy ridge on this really strange moon.
27:45How do you form a smooth equatorial mountain ridge around an entire world?
27:50A really interesting idea is that for some period of time, just like Saturn itself has this gigantic
27:57ring system, Iapetus had a ring system as well.
28:02Over time, Iapetus's ring collapsed, falling in a circle around the moon.
28:11As it fell to the surface, it built up a mountain range right below where the ring was orbiting.
28:16So that all that material just built up and built a mountain range,
28:19ringing the equator all the way around.
28:26Walnut-shaped, Iapetus is not the only strange moon around Saturn.
28:31Cassini discovered a moon hiding many secrets beneath its icy surface.
28:37Enceladus, a moon that could even harbor life.
28:46In August 2017, Cassini captured six images of Enceladus,
29:10one of the most intriguing moons in the solar system.
29:12Enceladus is a relatively small moon of Saturn that's pretty easy to ignore,
29:20but once you pay attention to it, hosts a lot of surprises.
29:24We've known something was unusual about this icy world ever since the Voyager mission took photographs in 1980.
29:37We thought that Enceladus would be frozen solid, and yet we knew from Voyager data,
29:45the surface of Enceladus was bright white.
29:48And we could see on the surface that vast tracks of it were smooth, at least at the resolution that we had with Voyager.
29:57And that immediately says that there's been internal activity, because that's really on an airless moon.
30:04That's the only process that could erase craters.
30:09Scientists suspected something was actively resurfacing Enceladus,
30:15filling in its craters to make it smooth and bright.
30:18Then, Cassini sent back pictures of Enceladus backlit, and all was revealed.
30:27We saw these icy jets shooting out from Enceladus, and everyone was so amazed that a moon so tiny,
30:35and as soon to be a frozen solid ice cube, could be so active.
30:46Jets of almost luminous material spraying out of geysers.
30:51When I first saw a picture of a geyser on Enceladus, I mean, I was floored.
30:57That's amazing. I had no idea that that was even possible.
31:01The Cassini discovery of geysers on Enceladus was a game changer.
31:07All of a sudden, here's water jetting out. It was, like, too good to be true.
31:13Cassini revealed the geysers are blasting out liquid water.
31:17Enceladus is not a solid ball of ice.
31:23As we got more data from Cassini, we found that Enceladus had a wobble that was too large
31:28for a body that was frozen solid all the way through,
31:32and that told us that a liquid water ocean circled a rocky core.
31:37Enceladus has liquid water under its surface, and it may very well be an ocean,
31:42basically covering the inside of that moon. But where's the heat coming from?
31:47When planets and moons form, their cores are incredibly hot.
31:55But over time, they cool down. The smaller the planet, the faster it cools.
32:00A tiny world like Enceladus, over a billion miles from the sun, should have frozen solid by now.
32:11That's what we expected. If things are smaller, then they would be roughly dead,
32:15and they'd be covered by craters. But Enceladus shows us that that's not the case at all.
32:19How could a tiny moon, so far from the sun, have enough warmth for liquid water? One idea is tidal heating.
32:29If you've ever played racquetball, you know as you play the game, the ball heats up. And this is because
32:35as the ball hits the racquet or the wall, it's getting squished and then it relaxes.
32:43Saturn's gravity squishes and relaxes Enceladus as it orbits the planet, heating it like a racquetball.
32:50But this alone wouldn't generate enough heat to stop Enceladus's water from freezing.
32:59Something else must be going on in the core.
33:02What if the core of Enceladus is actually kind of gravelly? Instead of it just being solid,
33:10it's actually made of rocks and pebbles and gravel all put together. Then what happens is,
33:15as the tides are stretching and squeezing it, those rocks are rubbing together,
33:20and that actually generates even more energy.
33:232017. A computer model based on Cassini data revealed this tidal friction generates more energy
33:35than America's biggest power station. Water, heated to 194 degrees Fahrenheit,
33:43rises to the surface. It sprays through cracks in the moon's south pole, creating misty plumes.
33:53As we flew seven times through and tasted and sampled the gas and the particles,
33:58we found salty particles, that the ocean was salty, very much like the Earth's ocean.
34:04We found hydrocarbons, methane, carbon dioxide, ammonia. We found the key ingredients for life
34:12coming out of the jets of Enceladus. So remarkable.
34:16In 2018, scientists reanalyzed the Enceladus data and found something even more remarkable.
34:30Complex organic molecules.
34:34What they found were larger organic compounds than initially thought there. At first,
34:39it was just dust and water and some basic organics. Now, they're seeing more complex
34:44stuff coming up from Enceladus' interior. And that asks the question, what else is down there?
34:52On Earth, we find life huddled around hot vents on the seabed. Could the same be true
34:59in the oceans of Enceladus? Could these complex organic molecules be signs of life?
35:06My favorite name for them is goo. They're gooey things. And think of life as a collection of
35:14gooey-like molecules. Now, that doesn't mean that all gooey molecules are biological,
35:18but certainly biology makes use of these complex organic molecules.
35:22Deep in Enceladus' oceans, heat from hydrothermal vents drives chemical reactions. Combining simple
35:33molecules like methane and hydrogen into longer, complex organic molecules.
35:41Complex molecules that could serve as the precursors to life.
35:46What's amazing is the chemistry of that ocean. Everything needed for life is there.
35:53The internal question is, is there life in the universe? And Enceladus is a great place to try
35:57and answer that question.
36:04And Cassini revealed secrets of another moon of Saturn with amazing chemistry.
36:09A giant moon with earth-like features. Rivers, lakes, and dunes. Titan.
36:27September 2017. Four days before the mission ended, Cassini flew past one of Saturn's most
36:45spectacular moons. Titan. Here's why I like Titan. Not just because it has a name that means big and
36:54strong, which makes you think of me, but because it has an extensive atmosphere that's made primarily
37:01of nitrogen, just like Earth.
37:07Titan's always been a mystery. What is hiding underneath that thick atmosphere?
37:17Feud through a telescope, this moon seemed little more than a hazy orange ball.
37:22Then Cassini launched the Huygens probe. It traveled beneath the clouds and sent back images of Titan's surface.
37:33I almost can't describe how thrilling it was. The landing of the Huygens probe on the surface of Titan.
37:43It was like a Jules Verne adventure come true.
37:45The images that you see as you're coming through the atmosphere and the world emerges. And it's this
37:59incredible world that looks so familiar. Mountains and these streams flowing into this ocean. Wow.
38:06You might be standing on the shores of a lake, but this lake doesn't look like water. Instead,
38:13it's methane. It's much darker. It's a frigid, bizarre world with geologic features that look familiar,
38:21but in a very, very alien setting. Titan is like a home away from home. It's just colder by about 350 degrees Fahrenheit.
38:31The Cassini mission revealed that Titan is really exactly like Earth in terms of its landscape. In fact,
38:38almost a quarter of the body is covered in sand dunes, exactly like what you see behind me.
38:43But Cassini reveals Titan's dunes are not what they seem.
38:55The dunes on Titan are made of something completely different than sand dunes on the Earth. We know most
39:00sand on the Earth is made of quartz. But on Titan, sand dunes, it turns out, are made entirely of organics.
39:06Titan sand is made from tiny particles of organic gunk called hydrocarbons.
39:20These organic dunes contain the building blocks of life. For scientists, this is a tantalizing hint.
39:31Could Titan harbor life?
39:36Here on Earth, there's life that exists in so many extreme environments. So it's not impossible to think that
39:45life could have evolved to use the methane and all of the other chemical constituents on Titan.
39:51If life has developed on Titan, it's going to look really weird. It's going to be really different from life on Earth.
39:58To me, there's going to be this wonderful moment in history when we really do have another example of how life can be.
40:04And if I had to place my bets on it, I think we're going to find it in the Saturn system.
40:11But Cassini's discovery of potential life sentenced the probe to death.
40:18We didn't want to leave it just indefinitely in orbit because there is this fear that,
40:23you know, should there be any earthly contamination on the spacecraft, you don't want it crashing into Titan or Enceladus.
40:34Cassini interacted with Titan one last time.
40:37With a gentle nudge from Titan's gravity, we call it Titan's goodbye kiss.
40:45We ended the mission with a plunge into Saturn's atmosphere, vaporizing Cassini and saying goodbye to our friend.
40:54I hope you're all as deeply proud of this amazing accomplishment.
41:06I'm going to call this the end of mission.
41:09Project manager off the net.
41:11Although Cassini is gone, its legacy lives on.
41:25Now we're sifting through all of the data collected, still finding discoveries, putting together the pieces
41:33of the puzzle to understand Saturn, the rings and the moons.
41:38Cassini is going to go down in history as one of the most scientifically productive interplanetary missions
41:44that humanity has ever flown.
41:48I'm immensely proud and feel enormously privileged to have been a part of it.
42:03Besides the amazing science Cassini returned, just the beauty of this planet, I think, sparked something inside of us.
42:13Whenever I look up at Saturn now, I know that Cassini is there too.
42:18And so Saturn is even a more special place.