Researchers were able to detect a near-invisible intergalactic gas filament connecting the three galaxy clusters that form a superstructure known as Abell 3391/95. Photo by Reiprich et al./Astronomy & Astrophysics
Dec. 17 (UPI) -- Astronomers have discovered a massive intergalactic gas filament measuring at least 50 million light years in length -- the longest yet to be found.
Intergalactic filaments are long threads of hot gas that weave their way through galaxies and link together galactic clusters.
Just five percent of the universe is made up of ordinary, or visible, matter. So far, astronomers have visually confirmed the existence of only about half that matter.
Previously, cosmologists have theorized that much of the universe's missing matter is hiding inside elusive intergalactic gas filaments.
The latest research, published Thursday in the journal Astronomy & Astrophysics, suggests they're right.
When the Big Bang exploded a tiny cloud of gas and dust, some 13.8 billion years ago, the universe's matter spread out nearly uniformly -- but not quite. Because some parts of the cloud were slightly denser than others, small pockets of the cosmos hosted stronger gravitational forces.
Over time, these pockets became increasingly concentrated with matter and, separated by greater expanses of emptiness, came to host galaxies and galaxy clusters.
At least, that's how scientists theorize the birth and evolution of our universe went down. If it did, then these pockets of galactic activity shouldn't be entirely isolated -- they should be connected by thin filaments of gas, researchers say.
"According to calculations, more than half of all baryonic matter in our universe is contained in these filaments -- this is the form of matter of which stars and planets are composed, as are we ourselves," lead author Thomas Reiprich, a professor at the Argelander Institute for Astronomy at the University of Bonn in Germany, said in a news release.
Because many of these filaments have been stretched so thin, they're exceptionally diffuse -- nearly impossible to see using traditional methods of observation. Thankfully, researchers have a new tool for finding intergalactic gas filaments, eROSITA.
"eROSITA has very sensitive detectors for the type of X-ray radiation that emanates from the gas in filaments," said Reiprich. "It also has a large field of view -- like a wide-angle lens, it captures a relatively large part of the sky in a single measurement, and at a very high resolution."
The newly identified filament was found linking the three galactic clusters that form the superstructure Abell 3391/95, which is located some 700 million light-years from Earth. The filament revealed in eROSITA's images of Abell 3391/95 measures 50 million light-years in length, but researchers suspect they're only glimpsing a small part of it.
"We compared our observations with the results of a simulation that reconstructs the evolution of the universe," said Reiprich. "The eROSITA images are strikingly similar to computer-generated graphics. This suggests that the widely accepted standard model for the evolution of the universe is correct."
The research suggests most of the cosmos' missing matter is hiding inside these near-invisible filaments, scientists say.