New baby images of the universe, taken by the James Webb Space Telescope, show galaxies have started forming faster and earlier than expected.
The telescope was launched in December and it now orbits the sun about a million miles from Earth. Its giant mirror allows it to detect faint light that has been traveling for almost the entire history of the 13.8 billion year old universe. This means he can actually see what galaxies looked like in the past.
Snapshots captured so far have both delighted and perplexed scientists, as it turns out that many bright galaxies existed when the universe was very young.
“Just a few hundred million years after the Big Bang, there are already a lot of galaxies,” says Tommaso Treu, an astronomer at the University of California, Los Angeles. “JWST opened a new frontier, bringing us closer to understanding how it all began.”
In research articles published in Letters from the Astrophysical JournalTreu and other astronomers report the discovery of a galaxy that dates back just 450 million years after inception, and another that dates back 350 million years.
This latest discovery broke a record set by the Hubble Space Telescope in 2016, when it managed to glimpse a galaxy called GN-z11, which existed around 400 million years after the Big Bang.
Astronomer Garth Illingworth of the University of California, Santa Cruz was part of the team that discovered GN-z11 and said seeing it was “a huge surprise”. But now, with the help of their new space telescope, scientists know it wasn’t just a strange outlier, because they have at least two more examples.
“These galaxies we’re talking about are bright, and so they were hiding just below the limits of what Hubble could do,” says James Webb Space Telescope Operations Project Scientist Jane Rigby. “They were just there waiting for us.”
Since astronomers started using JWST, some have claimed to have spotted even older galaxies, like 250 million years after the Big Bang. But these are more tentative observations.
“We’re very confident for these two, but less confident for the others,” says Illingworth. “There are certainly a lot of discussions going on.”
The two newly seen galaxies are both 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 the JWST, astronomers need to rethink their old ideas about the evolution of the universe.
“It’s exciting for us, from a theoretical point of view, that there may be open questions about how these galaxies could have formed their stars so much earlier than we are able to detect one. large number,” says Jeyhan Kartaltepe of the Rochester Institute. of Technology.
Finding galaxies like these and better understanding how the universe evolved into what it is today is why astronomers have spent decades and $10 billion designing and launching JWST.
“We can see that we’re really on the right track to realizing the dream of understanding galaxies as soon as possible,” says Illingworth. “The last few months have been exciting, but we still have a lot to learn.”
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