Tiny vibrating strings in string theory aren't the only ones of interest to physicists. The Standard Model of Particle Physics provides a theory about another type of string – this is a string of very thin gas strung over very long distances. In fact, the Standard Model predicts that a large percentage of "baryonic matter" (i.e., the type who makes up everything we see and interact with) would be contained in these filaments. And now scientists, led by a team from the University of Bonn, have discovered one of these super-long gas strands for the first time.
The part of the Standard Model that predicts these strings begins with the hyperinflationary period immediately after the Big Bang. According to the Standard Model, the only reason there is literally anything in the universe at all is because the sphere that was the early post-Big Bang expansion universe was slightly denser in some places than in others.
Simulation image of the gas distribution (left) compared to the observed X-ray image from eROSITA (right).
Photo credit: Reiprich et al., Astronomy and Astrophysics
These concentrations of matter drew other matter closer together through gravity and eventually created the first galaxies, stars, planets and everything else in the known universe. The Standard Model also predicted that these gravitational forces would also cause a tail of trailing particles, which would show up as a sort of path between where matter originally was and where it was pulled.
So far, however, it has been extremely difficult to detect these filaments because they are extraordinarily sparse. According to the best estimates, the concentration of gaseous particles is 10 particles per cubic meter. That is a much lower concentration than what even our best vacuum machines can create artificially.
Representation of two further Abell galaxies (Abell 399 & Abell 401), which are surrounded by a thin stamen.
Image credit: ESA
Such a dilute gas stream does not allow many conventional methods of direct detection. However, the team looking for these filaments had access to a new instrument – eROSITA, an X-ray telescope from the Max Planck Institute for Extraterrestrial Physics. For the first time, eROSITA was able to capture the X-rays emitted by these incredibly sparse gas clouds.
This gas cloud was observed while data was being collected on the Abell 3391/95 set of three galaxy clusters. Not only did it take data from the gas clouds, it also showed the galaxies that make up Abell and how the filament actually connects each galaxy to others in the cluster.
Lecture by Thomas Reiprich, one of the leading scientists and main author of eROSTIA on the filament paper, about what the telescope is designed for.
Photo credit: Reiprich / Astrophysics Research Center's YouTube channel
What's even more impressive, the research team doesn't believe they've observed the full extent of the filament themselves, even though the part they discovered was already more than 50 million light years long. The sheer size of these filaments would explain why theoretically up to 50% of all interactable matter is still hidden in them.
The data from eROSITA gives more credibility to the idea that the filaments are actually where this missing matter is hidden. But until more data is collected and these filaments are observed in more than one place, this new X-ray telescope and the scientists using it will have to find many more lines.
Astronomy & Astrophysics – Original Article
University of Bonn – Longest intergalactic gas thread discovered
Space.com – This intergalactic filament is 50 million light years long, the longest we have ever seen
ScienceAlert – Astronomers discover elusive 50 million light-years long threads tied to the cosmic web
Lead Image Credit: Optical image of the Abell galaxy cluster in which the X-ray work was carried out. Photo credit: Reiprich et al., Astronomy & Astrophysics