The James Webb telescope found the first ‘Green Pia’ galaxies in the universe

The galaxies that helped shape the early universe were probably small, round, and green.

Astronomers using the James Webb Space Telescope have dated “Green Pia” galaxies to 13.1 billion years old. These greenish streaks, spotted just 700 million years after the big bang, could have contributed to one of the biggest makers in cosmic history, astronomers said before a January 9 news conference in Seattle at the meeting of the American Astronomical Society.

Green peas first showed up in 2009 in images from the Sloan Digital Sky Survey, an ambitious project to map much of the sky. Citizen science volunteers have given various names to the objects. Their color is green, because more of their light comes from the vapors of the clouds than directly from the stars.

These galaxies are rare in the modern universe. Astronomers think they are analogous to galaxies, which were more abundant in the early universe.

“They’re a little like living fossils,” astrophysicist James Rhoads of NASA’s Goddard Space Flight Center in Greenbelt, Md. said. “Coelacanths, if you will,” he said, pointing out that the fish had become extinct until he reached the southern coast. Africa in 1938 (SN: 12/2/11).

These galaxies emit much more ultraviolet light, which can tear electrons from atoms, than typical galaxies. So the Green Pisa marked the first billion years of the universe or so could be partially responsible for a dramatic and mysterious transition called cosmic reionization, when most of the hydrogen atoms in the universe were stripped of their electrons (SN: 1/7/20).

Three ancient green peas were turned into the first JWST image, released in July 2022 (SN: 7/21/22). The objects in JWST’s infrared vision look red, but they emit wavelengths of light like those previously found in Green Peas. The findings were also published in 1 . Jan Literary Journal of Astrophysics.

“This helps explain how the universe is reionized,” Rhoads said. “I think that’s a big part of the puzzle.”