Space is so hot right now. The unmanned Artemis I mission is on its way to lunar orbit, the first in a series of missions that plans to return humans to the moon by the end of the decade. A spacewalk at the International Space Station went out this week and was streamed live. We’re hustling at asteroids to prove we can do it. And our new friend, the James Webb Space Telescope, is just doing its thing, quietly rethinking our entire understanding of how the universe works.
Hovering a million miles from Earth, the JWST sends back images that make the Hubble look like a real piece of shit. Understandably, Webb’s photos that make headlines are the stunning ones – the ones that are particularly beautiful or grand and awe-inspiring. Webb still takes a lot of it. But those more artistic images are, in a way, the telescope PR does to justify its existence to the wider public. The actual science is in the analysis of the less sexy data: things that don’t even exist in the visible spectrum, or in the close analysis of relatively unspectacular photographs. Yesterday’s big news comes from those everyday images.
I realize I run the risk of underestimating this, so: Naturally these statues are spectacular, even if they are not pillars of creation. And what they show, which is what is magnified in Figure 2 at the bottom center, is a brain-melting superlative. It is the galaxy GLASS-z12, which is believed to be 13.45 billion years old, or just 350 million years after the universe was created in the Big Bang. It’s the most distant starlight we’ve ever seen.
But it’s not the galaxy’s existence that gets scientists so excited — we already knew there would be galaxies around that time, and we knew the JWST’s superior imaging would reveal them. What was unexpected was how easy it was to find.
“Based on all the predictions, we thought we had to search a much larger volume of space to find such galaxies,” said Marco Castellano of the National Institute of Astrophysics in Rome, who led one of two research papers published Thursday. The Astrophysical Journal Letters. Scientists had a model, based on current understanding, for how many of these bright, fully formed galaxies would be there in the very early days of the universe. That model predicted it would take a stretch of sky about 10 times larger than what Webb recorded to find them. Instead, Webb quickly investigated two such galaxies, which scientists discovered within just a few days of the data being released for study.
What this means is that our models were wrong, and that bright, densely populated galaxies may have formed more quickly and more frequently after the end of the stellar dark ages—about 100 million years after the Big Bang, when conditions in the early universe finally made it possible to let gravity build up stars – than we could have ever imagined.
We were wrong! That’s so cool! Learning that we were wrong is the very literal point of science! Knowing that our models and predictions were inaccurate allows us to create new ones to better explain the observations, bringing us ever closer to being right. Science is iterative, and these little discoveries, rather than the big splashes, are how the JWST will help us write and rewrite the early history of our universe.
“These observations make your head explode,” said Paola Santini, a co-author of the Castellano et al. paper. “This is a whole new chapter in astronomy. It’s like an archaeological dig and suddenly you find a lost city or something you didn’t know. It’s just staggering.”
These two new young galaxies are already yielding some intriguing observations. That’s what they are much brighter than we expected, and brighter than anything else we have closer to Earth. “Their extreme brightness is a real puzzle,” said Pascal Oesch, a co-author of the second paper published today. But there is an attractive opportunity. It is assumed that stars in the very early universe would consist only of hydrogen and helium, simply because they had not yet had time to produce heavier elements through nuclear fusion. Those so-called Population III stars are said to be incredibly hot and incredibly bright, and while they’ve long been theorized, they’ve never been observed. Until, maybe, now.
This is hot shit in every way. Thanks, Webb.