When we observe the stars, we are inclined to think that they are distributed more or less uniformly. But it’s not the case at all. All the stars are part of a gigantic cosmic web that connects galaxies in the universe, like threads of an immense spider’s web, leaving large voids in between.
In two articles published in The Astrophysical Journal Letters on June 29 (ref.), scientists, using the now famous James Webb Space Telescope, describe in detail the evidence that this massive cosmic web dates back to almost the dawn of the universe.
James Webb and the primordial cosmic web
Using data from the space telescope, astronomers have discovered an enormous gaseous filament composed of 10 densely packed galaxies that stretch over 3 million light-years. According to the researchers, this ancient filament of gas and stars could represent the oldest known thread of the cosmic web.
“I was surprised at how long and thin this filament is” said Xiaohui Fan, an astronomer at the University of Arizona and a member of the research group. “I expected to find something, but I didn’t expect such a long and sharply thin structure”.
The newly discovered filament formed when the universe was young, just 830 million years after the Big Bang. It is anchored to an extremely luminous celestial object with a quasar at its center. This bright quasar is the reason scientists discovered the filament in the first place.
Studying quasars and black holes
Fan and his team are working as part of the ASPIRE (A Spectroscopic Survey of Biased Halos in the Reionization Era) project, which aims to study how the first black holes influenced galactic evolution. The quasar detected here was one of the 25 quasars from the primordial universe that the project has had its eyes on for some time.
“This is one of the first filamentary structures that people have ever found associated with a distant quasar” said Feige Wang, an astrophysicist at the University of Arizona and the principal investigator of the program.
The researchers also hypothesize that black holes contributed to the formation of the cosmic web by acting as gravitational wells to gather matter. Occasionally, they would sling the matter away on “cosmic winds” which move around extremely active quasars. Gravity keeps these filaments of stars and dust connected, even as the winds propel them through the universe. The researchers believe that eventually, the filament will condense into a galaxy cluster, similar to the Coma Cluster, located about 330 million light-years from Earth.