SCOTT DETROW, HOST:
NASA's James Webb Space Telescope has revealed yet another marvel from deep in outer space. A galaxy named MoM-z14 has taken the title of most distant galaxy the telescope has captured. It is a mind-boggling 13.5 billion light years from Earth, and that means the light we see from the galaxy has been traveling to us practically since the Big Bang. This is also the oldest galaxy we have ever seen. It was formed not long after the Big Bang, relatively speaking. Here to help us understand this is Harley Katz. He's an assistant professor of astronomy at the University of Chicago. Welcome to ALL THINGS CONSIDERED.
HARLEY KATZ: Thanks.
DETROW: So we're talking about 280 million years after the Big Bang, which, to us as humans, sounds like an incredibly long time. But can you put that timeline in a cosmic perspective for us?
KATZ: Sure. It's remarkably short, if you think about it. So overall, the universe is about 14 billion years old, OK? And when the universe started, it was pretty much a hot ball of hydrogen and helium. And in order to form a galaxy like MoM-z14, it actually took a little bit of time for the universe to cool down enough such that the gas could condense enough and stars can form such that we're able to see them. So really, it's basically one of the first galaxies we're possibly ever able to see, which makes it such a remarkable achievement.
DETROW: Before we keep talking about MoM-z14 and similar discoveries, help us understand why this information matters. Why is it so important for astronomers to see this evidence, to see what we're now taking in from the web telescope?
KATZ: When the universe started, it was just pretty much hydrogen and helium. So how do we go from this hot ball of hydrogen and helium to the diversity of, you know, galaxies and objects that we see today? - is still a relatively large mystery. And that first generation of stars, galaxies and black holes, that's really where the large uncertainty lies. And the reason is because up until James Webb, we never actually had any observational data in order to help us understand the physics of the early universe. So now that we keep finding galaxies earlier and earlier in cosmic time, we can finally bridge that gap between the big bang and this remarkable set of objects we see in our night sky.
DETROW: So again, early on, preliminary information, what jumps out to you about MoM-z14?
KATZ: Well, first, its brightness - that's one of its remarkable aspects. In fact, if you look at most of the theoretical models for how galaxies form in the early universe, very few of them predicted the galaxies would be as bright as MoM-z14. So just the fact that we see anything at these early cosmic times is really quite a change in our understanding of how galaxies form in the early universe. And I would say the second thing that sticks out - and it's a pretty remarkable achievement of the telescope itself - is we can actually see individual elements inside of the galaxy. So for example, one of the things they discovered was that there seems to be an overabundance of nitrogen, and there's not a single theoretical model that predicted this much nitrogen this early on.
DETROW: What does that mean, then? Like, is this, like, a literal existential question then for you and your field? Or, like, what is the best way to think about this?
KATZ: I think it's great because it gives us theorists a lot to think about. You know, prior to James Webb, we were using our best guesses of what was going on, and sometimes, you know, those best guesses are based on what you can currently see, and if things are different, it's not so surprising. And there's been a number of proposals out there for what it could be, but there's no concrete evidence right now for any individual idea.
DETROW: You know, given the pace of all of these discoveries - the James Webb telescope has been operating for just about three years now at this point - like, how different do you think our understanding of the universe could be in a decade, in two decades, given this pace we've seen so far?
KATZ: I mean, if it keeps up, we're going to need more theorists in the field to figure out what's going on. There's no question about that. I don't know how many more objects like MoM-z14 are going to be found. We might get lucky and push the frontier a little bit further back in terms of cosmic time.
DETROW: Yeah.
KATZ: That being said, there's still a huge discovery space that is in between around a billion years after the Big Bang and sort of MoM-z14, which, as you said, is a few hundred million years after the Big Bang. And what James Webb's going to do there is it's just going to take deeper and deeper images and spectra, which really allows us to elucidate the physics of what's going on.
DETROW: That's Harley Katz, an assistant professor of astronomy at the University of Chicago. Thanks so much.
KATZ: Good to be with you. Transcript provided by NPR, Copyright NPR.
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