NASA’s Webb has found spiral galaxies that formed earlier than we ever imagined

Like most good science, large telescopes often end up creating more puzzles than they solve. This is certainly the case with NASA’s Webb Space Telescope, whose early deep-sky observations kept pushing the epoch of galaxy formation to earlier and earlier times and higher and higher redshifts.

It is now clear that there is something wrong with current theories of cosmology.

In another new set of deep-sky observations by the Webb Space Telescope, a University of Missouri-led team found an unexpected number of spiral galaxies that have thin disks and were present some two billion years after the Big Bang itself.

In an article published in The Astrophysical Journal Letters, a team of researchers from the University of Missouri in Columbia used NASA’s Webb Telescope to observe some of the first spiral galaxies ever discovered. They were surprised to find that these early galaxies were not only more common than previously thought, but that they had already developed fully formed spiral arms and disks not unlike what we find in our own Local Group of galaxies.

Our work suggests that spiral galaxies formed several billion years earlier than previously believed, Vicki Kuhn, the paper’s lead author and a graduate student in astronomy at the University of Missouri, told me by email.

The Missouri team found that nearly 30 percent of the observed galaxies developed a spiral structure during the first two billion years in the universe. Not only did the formation of galaxies occur much faster than previously thought, but the old paradigm that most spiral galaxies developed around half the current age of the universe will likely have to be revised.

The team used Webb’s Cosmic Evolution Early Release Science Survey (CEERS) to visually identify spiral galaxies, the authors note. Of the 873 galaxies, 216 were found to have a spiral structure, they write.

We use only one small sky probed by the CEERS program, Yicheng Guo, an astronomer at the University of Missouri and one of the paper’s co-authors, told me by email. It’s an area of ​​the sky that’s comparable to the tip of a pinhead held in a pitching arm, Kuhn says.

This is a stunning little piece of sky watching. As Guo is quick to point out, it may have been just luck that the team was able to spot these early spiral galaxies at such early times in the universe.

The disks make up the galaxy

Our Milky Way is a disk galaxy with spiral arms; it’s a “thin” disc, says Guo. People believed that the disks in the early universe were thick, and that those thick disks had to first become thin disks, he says. And then create spiral arms in them, says Guo. But our work suggests that the thinning and formation of the spiral arms happened at the same time during the first few billion years of the universe, he says.

What lies ahead?

Webb is expected to make larger and deeper observations to expand the Missouri team’s analysis of high-redshift spiral galaxies, the team said in their paper.

What is the most mysterious?

The percentage of spiral galaxies we see is surprisingly flat over a wide range of cosmic time, from two billion years after the universe formed to about 7 billion years after the Big Bang, Guo says.

This means that the start of spiral formation was even earlier than when the universe was 2 billion years old, he says. This means that even with the Webb telescope, we have not explored the true onset of spiral galaxies in the universe, Guo says.

Reevaluate

So we may have to rethink our understanding of galaxy formation, Kuhn says.