Hubble would be transformational, but astronomers knew its capabilities would be limited by its observations in visible light. So, Illingworth and a handful of others got to work, drawing up concept ideas for what became known as the Next Generation Space Telescope (NGST), later renamed as JWST after a former NASA administrator. But Giacconi was insistent: “Trust me, it'll take a long time,” he said. “I protested, saying we've got more than enough to do on Hubble,” Illingworth recalls. But Garth Illingworth, then deputy director of the STScI, was surprised one day when his boss, then director Riccardo Giacconi, who died in 2018, asked him to start thinking about what would come after Hubble much farther down the road. At the time the Hubble Space Telescope was still five years away from launching on a space shuttle. One might say JWST's observations of early galaxies have been billions of years in the making, but more modestly they trace back to the Space Telescope Science Institute (STScI) in 1985. “You build these machines not to confirm the paradigm but to break it,” says JWST scientist Mark McCaughrean, a senior adviser for science and exploration at the European Space Agency. ![]() JWST's early revelations could rewrite the opening chapters of cosmic history, which concern not only distant epochs and faraway galaxies but also our own existence here in the familiar Milky Way. Could the bevy of anomalously big and bright early galaxies be illusory, perhaps because of flaws in analysis of the telescope's initial observations? If genuine, could they somehow be explained by standard cosmological models? Or, just maybe, were they the first hints that the universe is more strange and complex than even our boldest theories had supposed?Īt stake is nothing less than our very understanding of how the orderly universe we know emerged from primordial chaos. In the weeks and months following JWST's findings of surprisingly mature “early” galaxies, theorists and observers have been scrambling to explain them. “Everyone was freaking out,” says Charlotte Mason, an astrophysicist at the University of Copenhagen. The competition for discovery was fierce: with each new day, it seemed, claims of yet another record-breaking “earliest known galaxy” emerged from one research group or another. Instead, as soon as the telescope's scientists released its very first images of the distant universe, astronomers such as Naidu (at the Massachusetts Institute of Technology) started finding numerous galaxies within them that, in apparent age, size and luminosity, surpassed all predictions. Such observations were supposed to take time initial projections estimated the first galaxies would be so small and faint that JWST would find at best a few intriguingly remote candidates in its pilot investigations. By glimpsing galaxies from cosmic dawn with JWST, cosmologists can test their knowledge of all these underlying phenomena-either confirming the validity of their best consensus models or revealing gaps in understanding that could herald profound new discoveries. How exactly this process unfolded depends on exotic physics, ranging from the uncertain influences of dark matter and dark energy to the poorly understood feedbacks between starlight, gas and dust. This is the scarcely probed era-no more than a few hundred million years after the big bang itself-in which the very first stars and galaxies coalesced. Stationed 1.5 million kilometers away from earthly interference and chilled close to absolute zero by its tennis court–sized sunshade, the telescope's giant segmented mirror and exquisitely sensitive instruments were designed to uncover details of cosmic dawn never before observed. JWST-the largest, most powerful observatory ever launched from Earth-was built to revolutionize our understanding of the universe. ![]() The discovery of this galaxy, just weeks into JWST's full operations, was beyond astronomers' wildest dreams. “It reverberated around the world,” Naidu says. Days later they published a paper on the candidate galaxy, which they dubbed “GLASS-z13.” The Internet exploded. “I told her, ‘This might be the most distant starlight we've ever seen.'” After exchanging excited messages with one of his collaborators “with lots of exclamation marks,” Naidu got to work. “I called my girlfriend over right away,” Naidu says. It had sifted out an object that Naidu recognized was inexplicably massive and dated back to just 300 million years after the big bang, making it older than any galaxy ever seen before. As his algorithm dug through early images from the James Webb Space Telescope (JWST) late one night in July 2022, Naidu shot to attention. Rohan Naidu was at home with his girlfriend when he found the galaxy that nearly broke cosmology.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |