In the hype leading up to its launch, the James Webb Space Telescope was heralded as the next generation of space telescope.

It was going to peer through the fog of the universe and answer questions about how everything, including us, came to be. And, like, guilty, ‘cause nobody hyped it more than we did.

There was a stretch there where a whole lot of our videos ended with ‘and when Webb launches, we’ll find out more!’ So when it eventually did launch, on Christmas Day 2021, it carried all of our scientific hopes and dreams with it. I know at least one member of our team was screaming joyful obscenities at 5 am while doing last-second holiday baking. It took some time to be fully deployed, but by now Webb has had about a year and half to prove itself in space.

Has it lived up to the hype? [Intro music] There’s no doubt that Webb is the most ambitious space telescope ever launched. Taking over 30 years of development, and costing around $10 billion, it was a project that involved thousands of engineers and scientists worldwide. In part because of its complexity, the project suffered more than a decade of delays.

Like the sequel to Avatar, there was a time when we were all wondering if it would ever launch! But launch it did, and after a nail-biting journey  of 1.5 million kilometers, and six tense months of commissioning, it finally came online for scientific operations in July 2022. Since then, we’ve been treated to some of the most incredible images of our universe— from the cosmic cliffs of the Carina Nebula, to gravitationally lensed galaxies in deep space, and even the gossamer rings around our own distant neighbor Neptune.

And we love pretty pictures. But Webb has also made some pretty heavyweight discoveries that are already changing the way we think about the universe. Like the galaxies that seemed to break physics.

Don’t worry, they didn’t, but things looked a little  spicy for a while there. While using its sensitive infrared instruments to peer into the furthest corners of the universe, the telescope spotted galaxies that were much brighter, and way more distant, than expected. Webb’s data suggested that the earliest galaxies formed less than 400 million years after the Big Bang.

And they weren’t alone. Astronomers were astonished to see so many bright galaxies within the universe’s first billion years, when only a small fraction of stars even existed. It takes time to assemble stars into big structures like galaxies, and these early examples were an order of magnitude more massive than scientists thought possible.

So some scientists, and a lot of media outlets, jumped on the idea that our whole standard model of cosmology was wrong, including the timing and mechanism of the Big Bang, and how physics worked in the early universe. But over the next few months, astronomers got their heads together and figured out a few theories that didn’t involve throwing away everything we thought we knew. It seems that galaxies did grow about ten times faster in the early universe, and that might be down to dark matter, gas, and young stars behaving differently at that time.

Further analysis has shown that some of these early galaxies are surrounded by brightly glowing clouds of gas. Gas doesn’t tend to glow on its own, so scientists think it’s shining so brightly because it’s being illuminated, and energized, by big, hot, young stars nearby. They suggest this interaction could have triggered huge bursts of star formation early on, making galaxies grow bigger, faster.

But there are more curiosities to be found in Webb’s observations of cosmic dawn. At the hearts of some of the earliest galaxies, there seem to be the hallmark signs of some very big black holes. So big, in fact, that they’re officially classed as supermassive.

Now, supermassive black holes can be found in the centers of virtually all large galaxies today, but their origins are a bit of a mystery. There are two leading theories for how they form. The ‘small seed’ theory suggests that a star lived and died to form a small, stellar black hole, which then gradually gathered matter and other stars until it reached supermassive size.

But the other, ‘large seed’ theory suggests that a colossal cloud of gas collapsed directly to form a supermassive black hole. Thanks to Webb, it looks like we may have resolved these competing hypotheses. One such black hole found by Webb is relatively small , “only” 9 million times the mass of our Sun.

But it’s also old, dating to just 570 million years after the Big Bang. And only Webb could have spotted it in such detail. Scientists say that with Webb’s incredible ability to detect infrared light, they have as much data to work with as they do with modern supermassives.

Not bad for something that’s more than 13.2 billion years old! This black hole got rolling so early in the universe’s lifespan that it probably didn’t have time to grow from a small seed. Another ancient black hole, this time spotted with the help of the Chandra X-Ray observatory, is the oldest supermassive black hole ever detected.

Dating to 470 million years after the Big Bang, it’s even bigger than the  one Webb found on its own, at 10 to 100 million times the mass of our Sun., That makes the small seed theory… pretty unlikely. There’s too much black hole, and too few stars to feed it. So scientists are certain that this black hole formed from collapsing gas instead.

Whether this is true for all supermassives remains to be seen, but it’s still exciting to find such compelling  evidence in the early universe. But the telescope hasn’t just been peering into  the mysteries of deep time. It has also set its sights  on targets closer to home.

Among these, it’s been scanning the surfaces of exoplanets orbiting other stars in our galaxy, using its spectral and infrared instruments to probe their atmospheres and take their temperatures. Like WASP 39b, a hot, Saturn-sized planet orbiting close to its star 700 light years away. In the past, other telescopes have been able to pick out just a few components of its atmosphere, but Webb has given us the full ingredients list.

The complete chemical profile includes things like sodium, potassium, water, carbon dioxide, carbon monoxide, and sulfur dioxide. The types and ratios of heavier elements in this planet’s atmosphere tell scientists that its formation was probably a violent one, involving lots of collisions with other solid bodies in which the giant WASP-39b came out on top. Webb also scanned the surface of TRAPPIST-1c, one of seven rocky planets in close orbit around a red dwarf star 70 light years away.

The exoplanet was previously  thought to be like Venus, with a thick carbon dioxide atmosphere, but from Webb’s thermal profiles, scientists concluded that it probably has no atmosphere at all. This is something that only Webb could have seen. The precision of measurement needed is like looking at 10,000 tiny light bulbs and noticing that four have gone out.

Finally, in September 2023, Webb spotted a very exciting molecule in the atmosphere of K2-18b, 120 light years away. The planet is more than 8.5 times the mass of Earth, and is orbiting within the habitable zone of its star. Atmospheric profiles revealed methane and carbon dioxide in its atmosphere, but also dimethyl sulfide, which on Earth is only known to be made by phytoplankton in the ocean.

Don’t break out the “Aliens” guy memes just yet, though. There are still many, many questions to be answered before we can even start thinking this could be life on another world. But Webb will certainly play an active part in addressing them as well.

In the last year and a half, the James Webb Space Telescope has transformed our view of the cosmos, peering through dust clouds to see hidden treasure, and back through time to see our own confounding origins. But scientists say they’re just getting started. They say Webb’s first year was something of a warm-up, and now it’s ready to actually get cracking.

If all this stuff wasn’t cracking already, I can’t wait to see what’s next. Thank you for watching this episode of SciShow, and thank you to the patrons who made it possible. I bet some of you have been around for long enough to remember when we were hyping up Webb every other episode, and doesn’t it feel good to see the payoff? It’s exactly that long-lived community that makes what we do here possible.

And we’ve got all sorts of  great stuff to say “thanks.” Like live streams and some little behind-the-scenes peeks. We’re glad to have you whether you joined years ago or last week. If you’d like to check it out and get involved, you can head over to Patreon.com/SciSho [ OUTRO ]