Astronomers have found the "lost" matter of the Universe thanks to cosmic radio bursts
Kyiv • UNN
Astronomers have for the first time discovered the missing matter in the Universe using fast radio bursts (FRB). These signals helped to weigh the intergalactic fog, confirming theories about the distribution of matter.
Astronomers have for the first time managed to detect previously invisible matter in the Universe, which was long considered missing. They used mysterious fast radio bursts (FRBs) as a kind of spotlight that "shines through" space, helping to weigh the intergalactic fog and thereby confirm theoretical predictions about the distribution of matter in the Universe. UNN writes about this with reference to Space.
For decades, scientists have been unable to find almost half of the ordinary matter that should theoretically exist in the Universe. This is not about dark matter, which remains one of the biggest mysteries of modern physics, but about ordinary, baryonic matter, that is, the matter that makes up stars, planets, people, and everything around them. Finally, researchers have managed to trace where this missing substance is hiding, and cosmic signals known as fast radio bursts (FRBs) helped them do so.
What are FRBs and how did they help
Fast radio bursts are extremely powerful radio wave pulses that last only a few milliseconds, but manage to emit as much energy as the Sun in decades. Their origin remains a mystery - most of them occur only once, without repetition, which complicates research.
However, one thing was known for sure: FRBs travel through intergalactic space and interact with matter that cannot be seen through a telescope along the way. This interaction - the slowing down and scattering of the signal - allows scientists to calculate the amount of matter that radio waves pass through.
Fast radio bursts shine through the fog of the intergalactic medium, and by accurately measuring how the light slows down, we can weigh this fog, even when it is too faint to see it.
How the experiment was conducted
For their work, the team used 69 fast radio bursts recorded at distances from 11.7 million to over 9 billion light-years. One of the signals, FRB 20230521B, became the most distant of all known to date - thanks to such data, it was possible for the first time to directly observe the distribution of baryonic matter in intergalactic space.
Of the 69 signals mentioned, 39 were detected by a system of 110 radio telescopes at the Owen Valley Observatory (California), known as the Deep Synoptic Array (DSA). Other signals were provided by the Palomar Observatory, the W.M. Keck Observatory in Hawaii, and the Australian ASKAP array.
These data allowed scientists to see how FRB light scatters - like white light passing through a prism and forming a rainbow. By measuring this scattering, the researchers were able to determine the amount of matter the signal passed through.
It's like we're seeing the shadow of all the baryons, with the FRB as the backlight. If you see a person in front of you, you can learn a lot about them. But even when you only see their shadow, you still understand that they are there, and you can estimate their size.
What was found out
The results of the study showed that approximately 76% of ordinary matter in the Universe is contained in the intergalactic medium - a kind of "fog" scattered throughout the space between galaxies. Another 15% is in the halo around the galaxies themselves, and only 9% is directly inside them, in the form of stars, dust and cold gas.
This distribution is fully consistent with theoretical models and computer simulations, but this study was the first direct observational confirmation of such calculations.
This discovery not only fills a large gap in our understanding of the structure of the Universe, but also opens up new horizons for cosmology. The next step should be the launch of a new generation of radio telescopes - the DSA-2000 system, which is planned to be built in the Nevada desert. It will be able to detect up to 10,000 FRBs every year, significantly expanding the possibilities for observing and analyzing the intergalactic medium.
We have just demonstrated that FRBs can be used to "weigh" matter in the Universe. But the potential of this tool is much greater - it will help us take a fresh look at the evolution of galaxies and the very nature of space.