The most exciting thing in science is when we realize we were wrong
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 plan to return humans to the moon by the end of the decade. Space walk in The International Space Station went down this week and it was broadcast live. Were smacking asteroids to prove we can. And our new friend, the James Webb Space Telescope, is just doing its job, quietly reshaping our entire understanding of how the universe works.
JWST drifts millions of miles from Earth and sends back images that make Hubble look like real junk. Understandably, it’s the Webb photos that get the headlines the mind blowing ones— photos that are particularly beautiful or majestic and awe-inspiring. Web still accepting many of these. But these more artistic images are, in a sense, the telescope doing its PR to justify its existence to the general public. Real science takes place in the analysis of less sexy data: things that aren’t even in the visible spectrum, or in the careful analysis of relatively bland photographs. Yesterday’s big news came from these daily images.
I realize I risk understating this, so: Of course these images are impressive even if they are not Pillars of creation. And what they show—namely, what’s enlarged in Figure 2 in the bottom center—is a mind-melting superlative. It is a GLASS-z12 galaxy and is believed to be 13.45 billion years old, or just 350 million years after the creation of the universe in the Big Bang. It’s the most distant starlight we’ve ever seen.
But it’s not the galaxy’s existence that has scientists so excited—we already knew there would be galaxies from back then, and we knew JWST’s superb imaging would reveal them. What was unexpected was how easy it was to find.
“Based on all the predictions, we decided that we would have to search a much larger volume of space to find such galaxies,” said Marco Castellano from the National Institute of Astrophysics in Rome, which he directs one on two research papers published on thursday in The Astrophysical Journal Letters. Scientists had a model, based on current understanding, of how many of these bright, fully formed galaxies in the earliest days of the universe would have been there. This model predicts that a patch of sky about 10 times larger than the one Webb imaged would be needed to find them. Instead, Webb quickly studied two such galaxies that scientists discovered only a few days after the publication of the study data.
This means that that our models are 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 allowed gravity to start building stars—than we ever imagined.
We were wrong! This is so cool! Learning that we were wrong is literally what science is all about! Knowing that our models and predictions are inaccurate allows us to make new ones to better explain observations, bringing us closer and closer to being right. Science is iterative, and these small discoveries, not the big showy images, are how JWST will help us write and rewrite the early history of our universe.
“These observations just make your head explode,” said Paola Santini, co-author of 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 existed. It’s just mind-blowing.”
These two new, young galaxies are already providing some intriguing observations. Namely they are much brighter than we expected them to be, and brighter than anything else we have closer to Earth. “Their extreme brightness is a real puzzle,” said Pascal Ochs, co-author of the second paper published today. But there is an attractive possibility. It is hypothesized that in the very early universe stars would have been composed of only hydrogen and helium, simply because they had not yet had time to produce heavier elements through nuclear fusion. These so-called Population III stars would be incredibly hot and incredibly bright, and although they have long been theorized, they have never been observed. Maybe until now.
This is hot shit in every sense. Thanks, Webb.