For the first time, a team of scientists led by the University of Bonn observed a 50 million light-years long gas filament. Its structure is strikingly similar to the predictions of computer simulations. The discovery confirms the ideas of scientists about the origin and evolution of the Universe.
We owe our existence to a tiny aberration. Exactly 13.8 billion years ago, the Big Bang occurred. This is the beginning of space and time, and of all matter that makes up the universe today. Although the matter was originally concentrated at a single point, space expanded at breakneck speed in the form of a giant gas cloud, in which matter was distributed almost evenly.
Almost, but not completely: in some parts, the clouds were slightly denser than others. And only for this reason planets, stars and galaxies exist today. The fact is that denser areas exhibit higher gravitational forces that attract gas from the environment to them. Therefore, over time, more and more matter was concentrated in these regions. However, the space between them became more and more empty. Over the course of 13 billion years, a kind of spongy structure has formed: large “holes” without any matter with regions between them, where thousands of galaxies are gathered in a small space in the form of clusters.
If the theory is correct, galaxies and clusters should still be linked by the remnants of this gas, like a cobweb. “It is estimated that more than half of all baryonic matter in our universe is contained in these filaments: it is the form of matter that makes up stars and planets, just like ourselves,” explains Professor Dr. Thomas Reiprich of the Argelander Institute for Astronomy at the University of Bonn. However, these fibers could not be observed earlier: due to the huge expansion, their substance is diluted. It contains only ten particles per cubic meter.
However, with a new measuring instrument, the eROSITA space telescope, Reiprich, and his colleagues could see the gas in full for the first time. “EROSITA has susceptible detectors for the type of X-ray radiation that comes from the gas in the filaments,” explains Reiprich. “Its large field of view also helped: like a wide-angle lens, it captures most of the sky in one measurement at a very high resolution.” This allows you to obtain detailed images of huge objects such as fibers in a relatively short time.
In their study, scientists examined a celestial object called Abell 3391/95. It is a system of three galaxy clusters located about 700 million light-years away. EROSITA images show not only clusters and numerous individual galaxies but also gas filaments connecting these structures. The entire filament is 50 million light-years long. But it could be even bigger: Scientists speculate that the images show only part of the fiber.
“We compared our observations with the results of simulations that reconstruct the evolution of the universe,” explains Reiprich. “EROSITA’s images are strikingly similar to computer graphics. This suggests that the widely accepted standard model of the evolution of the universe is correct.””