New pictures of the baby universe, taken by the James Webb Space Telescope, show that galaxies started forming faster and earlier than expected.
The telescope returned in December and now orbits the sun about a million miles from Earth. Its giant mirror allows it to detect the faint light that has traveled through almost the entire 13.8 billion-year history of the universe. In this way, one can effectively see what galaxies have gone back in time in a similar way.
The snapshots taken so far have so shocked and puzzled scientists that it turns out that many bright galaxies existed when the universe was very young.
“A few hundred million years after the Big Bang, there are already lots of galaxies,” says Thomas Treu, an astronomer at the University of California at Los Angeles. “JWST has opened up new frontiers that bring us closer to understanding how it all began.”
In published research papers Journal of the Astrophysical SocietyTreu and other astronomers report the discovery of one galaxy that goes back to only 450 million years after the beginning, and another that goes back to 350 million years.
That discovery broke the record set by the Hubble Space Telescope in 2016, when it discovered a galaxy called GN-z11, which existed about 400 million years after the Big Bang.
Astronomer Garth Illingworth of the University of California, Santa Cruz, was a member of the team that discovered GN-z11 and says he saw “a big surprise.” But now, with the help of a new space telescope, scientists know that fate isn’t just an outlier — they have at least two examples.
“These galaxies we’re talking about are bright, and so they were hidden below the limits of what Hubble could do,” said Jane Rigby, scientific operations scientist for the James Webb Space Telescope. “They were right there waiting for us.”
When astronomers started using JWST, some claimed to have spotted galaxies from even earlier times, like 250 million years after the Big Bang. But those observations are more tentative.
“We’re very confident about those two, but less confident about the others,” Illingworth said. “There’s definitely a lot going on.”
Two galaxies have been spotted recently and are much smaller than our home galaxy, the Milky Way, and one appears to be unexpectedly elongated.
Because so many early, bright galaxies have been seen by JWST, astronomers have had to rethink ancient ideas about the evolution of the universe.
“It’s exciting for us from a theoretical point of view that maybe there are some open questions about how these galaxies formed their stars before we could detect large numbers of them,” says Jeyhan Kartaltepe of the Rochester Institute. of Technology.
Finding these galaxies and building a greater understanding of how the universe came to be what it is today is why astronomers spent decades and $10 billion dollars to design and launch JWST.
“We see that we are really on track to realize the dream of understanding the early stages of the galaxy,” says Illingworth. “The last few months have raised a few, but a huge amount remains to be learned before us.”
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