Four revelations about distant galaxies from the Web Telescope
NASA designed its state-of-the-art James Webb Space Telescope to peer into the distant universe and look back to the dawn of time — and it’s already doing it spectacularly. In the two weeks since the web’s first science images and data became available for astronomers to work with, they’ve reported a flood of preliminary discoveries, including several contenders for what could be the most distant galaxy ever seen.
Webb’s images reveal a wealth of galaxies shining in the distant universe, just as they did a few hundred million years after the Big Bang, 13.8 billion years ago. The telescope’s incredibly sharp pictures have shattered astronomers’ preconceptions about the early universe.
“We had an idea of what galaxies would look like at this [distance] and how much detail we would be able to see, but I think the reality is just the kind of thing that blows our minds,” says Jehan Cartaltepe. Astronomer at the Rochester Institute of Technology in New York.
Here are some things astronomers are learning from the first observations of the web.
There are a lot of scary galaxies out there
Because Webb detects infrared light, and because the expansion of the cosmos spreads light up to red wavelengths, the telescope is well-suited for detecting galaxies that formed early in the universe’s history. In the first observing program, which began in June, Webb discovered several distant galaxies beyond the reach of other observatories such as the Hubble Space Telescope.
“What many of us are arguing is that this suggests that there are galaxies beyond what Hubble saw,” says Richard Ellis, an astronomer at University College London.
The era of early galaxies began at the ‘cosmic dawn’, perhaps about 250 million years after the Big Bang, when the first stars formed and the universe was illuminated. Later generations of stars grouped themselves into galaxies, which are the faint red blobs that the Web began to detect.
Many of the web’s images are filled with never-before-seen galaxies in the distant universe. “There is no such thing as an empty space that contains nothing,” says Kartaltepe.
In a study Webb combed through data from the most distant galaxy regions ever seen to analyze the rate at which stars formed in the early universe. 44 previously unknown galaxies found spanning within 300 million years of the Big Bang. Combined with 11 previously known galaxies, the findings show that the early Universe 1 had a significant population of star-forming galaxies. The results “confirm the huge potential of upcoming large [web] events to change our understanding of the young universe”, the team led by Calum Donnan of the UK’s University of Edinburgh wrote in a paper on the arXiv preprint server. .
Many galaxies are competing for the title of ‘most distant’
Perhaps the highest-profile rush is the stampede of research teams to identify the most distant galaxy in web data. Several candidates have been discovered that need to be confirmed by further studies, but all of them break Hubble’s record for the most distant galaxy, which is about 400 million years after the Big Bang.