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00:00 The James Webb Space Telescope is humanity's greatest piece of observational equipment so far.
00:05 Launched on the 25th of December 2021, it's now orbiting the Sun roughly a million miles away,
00:12 where it's capturing groundbreaking images of our universe.
00:15 The telescope is designed to look deeper into space than anything before it,
00:19 and aims to study the universe's earliest stars and galaxies,
00:23 alongside a plethora of other topics such as planet and star formation.
00:28 2023 saw Webb release some of the most awe-inspiring images we've ever seen.
00:33 This is Unveiled, and today we're taking a closer look at the best James Webb images of 2023.
00:39 Do you need the big questions answered? Are you constantly curious? Then why not subscribe to
00:46 Unveiled for more clips like this one? And ring the bell for more thought-provoking content!
00:50 Let's begin with the Webb's beautiful observation of Cassiopeia A, a supernova remnant,
00:57 taken in April. For context, a supernova is the biggest explosion we know of.
01:02 At the end of a star's lifetime, once it's exhausted its fuel supplies,
01:07 there's no more outward pressure from fusion. As such, the star experiences a sudden gravitational
01:13 collapse and violently explodes. What's left over depends on the size of the star,
01:18 and can be either a neutron star, a black hole, or, in this scenario, a dazzling nebula of gas.
01:25 These spectacular images of Cass A bring a fresh insight into the complexity of supernova
01:30 remnant structures, and show us how intricate they really are. Cass A exploded roughly 340
01:37 years ago from Earth's frame of reference. It lies about 11,000 light-years away,
01:42 and is around ten light-years wide. Researcher Danny Milisalvavich of Purdue University,
01:48 Indiana, who worked on the images, said this is our best opportunity to, quote,
01:53 "run a kind of stellar autopsy" to understand what type of star was there beforehand and how that
01:59 star exploded. Webb's incredible tech has revealed new details about such processes, which were
02:04 previously impossible to know. One key feature of this image is the semicircle of red and orange
02:11 material along the top. This arises from interactions between ejected supernova debris
02:16 and neighbouring, circumstellar material. A vibrant, luminous pink ring can also be seen
02:22 in the photo. It's caused by heavy elements such as oxygen and neon, which were dispelled from the
02:27 star itself. Not everything is known about what's going on here, however, as there is a mysterious
02:33 and unexpected green loop in the central cavity as well. Astronomers are currently scratching
02:39 their heads at this, and have nicknamed it "the green monster", after the left-field wall at
02:44 Fenway Park, a famous baseball stadium in Boston. These aren't the only remnants of a once-vibrant
02:50 star to capture the attention of Webb in 2023, though, as it also imaged the popular and well-studied
02:56 Crab Nebula in October. The nebula lies 6,500 light-years away, in the constellation of Taurus,
03:03 and, amazingly, was first recorded in 1054 AD by Chinese and Japanese astronomers. At the time,
03:11 it wasn't the nebula itself they observed, but the explosion that birthed it, when it was visible
03:16 for a whole two years, and could even be seen during the day. Fast forward to now, and, while
03:23 in these recent images it bears little resemblance to a crab, we are able to accurately determine the
03:28 composition of what remains, thus revealing new information about the type of explosion and star
03:34 that came before it. In the center, creamy smoke trails are visible. This hasn't appeared so clearly
03:41 in prior observations, and has now been explained as arising due to synchrotron radiation. This is
03:47 radiation that's emitted from charged particles moving along curved paths at extremely high
03:52 speeds. The cause of this is a pulsar lying at the nebula's heart, which is essentially a neutron star
03:59 spinning extremely fast. In Webb's image, you can actually see where this pulsar resides,
04:05 from the circular patterns created by the wisps of gas in the center. Never before has an object
04:11 like this been photographed in such incredible detail, although it's likely we still have much
04:16 more to learn. Next up, let's look at Webb's stunning photo of the famous Ring Nebula,
04:22 taken in August 2023. Also known as M57, this object is a planetary nebula lying roughly 2,500
04:30 light years away from Earth. It's rather close to us in the grand scheme of things, as, for
04:35 comparison, the Milky Way is roughly 100,000 light years in diameter. Contrary to what you might
04:42 assume by its planetary descriptor, the Ring Nebula actually isn't linked to a planet. Planetary
04:48 nebulae are created from old, dying stars late in the stages of stellar evolution. Specifically,
04:54 they're red giant stars, which have depleted the majority of their core hydrogen needed to fuel
04:59 fusion. Instead, fusion will begin on the outer edges of the star's core. This means the core
05:05 will contract and get warmer, whereas the outer layers will do the opposite. And, during this
05:11 phase, massive quantities of gas are thrown from its outer layers. At the same time, the contracting
05:17 core will start to radiate large amounts of energy, which ionizes the outer layers on their way out.
05:23 This ionization is then what causes the vibrant colours seen in Webb's image.
05:28 We can also see soaring arcs surrounding the Ring Nebula, which imply the existence of a low-mass
05:34 companion somewhere orbiting the dying star. It's another image that truly opens our eyes to the
05:40 complexity and balance of space. Number four. And while Webb is more than capable of seeing distant
05:47 stars, it's also well-equipped to look a bit closer to home. In February, it took the most
05:53 successful images of Uranus ever produced. Webb's shots are a stunning contrast to earlier images
05:59 taken in 1986 by Voyager 2, in which the atmosphere of Uranus appeared to be bland,
06:06 with a lack of noteworthy features. Here, we see that isn't the case. A year earlier, in 2022,
06:13 Webb also captured breathtaking images of the planets Jupiter and Neptune, in particular
06:18 showcasing Neptune's rings with never-before-seen clarity. The new photos of Uranus reveal
06:24 similarly sparkling features about its neighbouring ice giant, displaying another
06:28 magnificent system of rings in orbit. Uranus shines brightly, with a spectacular blue glow.
06:35 Its polar cap can also be seen clearly, being the white circle on the right side of the image.
06:41 Usually, ice caps are at the top and bottom of planets. However, Uranus is peculiar in its
06:47 rotation. While Earth rotates about an axis tilted roughly 23 degrees, Uranus' axis of rotation is an
06:54 impressive 97 degrees. This means its rotation is almost perpendicular to its plane of orbit,
07:01 giving it these unique, sideways poles. As such, the planet is thought to possess an extremely
07:07 dynamic and harsh atmosphere, with a year on Uranus being 84 times what a year on Earth is,
07:14 implying seasons that last at least two decades. Finally, and again in August,
07:20 Webb took images of the galaxy cluster El Gordo, or "The Fat One". It's located more than seven
07:26 billion light-years away from Earth, and its mass is roughly 2.1 quadrillion times the mass of our
07:33 sun, making it the largest galaxy cluster we know of. It was formed 6.2 billion years after the Big
07:40 Bang, making it also the oldest astronomical object in this video. Gravitational lensing
07:46 is incredibly prominent here, an effect originally predicted by Einstein over a century ago.
07:52 Gravitational lensing occurs from objects so exceedingly massive that they distort and magnify
07:58 the light from objects behind them. This image includes multiple gravitationally distorted
08:04 galaxies. It also clearly shows the hundreds of galaxies that call El Gordo their home.
08:09 For example, El Anzuelo, or "The Fish Hook", can be spotted in the top right corner of Webb's image.
08:15 This is a bright red galaxy that appears curved, or hooked. In actuality, its geometry is much
08:22 less interesting, and it resembles that of a disc. But the curvature we see arises from El Gordo's
08:27 strong gravitational potential, which distorts the light that reaches us. Just to the left of centre,
08:34 a long, thin line can be spotted stretching across the photo, too. It's called La Flaca,
08:40 or in English, "The Thin One". Astronomers were also able to identify a red giant star,
08:45 called Coiler. This now holds the title of the most distantly observed red giant,
08:51 alongside being the only red giant seen over a billion light years away from Earth.
08:56 Throughout 2023, the James Webb Space Telescope has provided us with some awe-inspiring and
09:03 mind-boggling visualizations of space. With these, researchers are solving mysteries that
09:08 were previously impossible. And, with a further ten years or more planned for the mission in total,
09:15 there should be plenty more to watch out for in the future.
09:19 What do you think? Is there anything we missed? Let us know in the comments,
09:23 check out these other clips from Unveiled, and make sure you subscribe and ring the bell for
09:27 our latest content.