Astronomer student finds missing galactic matter

Most of the mass of the Universe consists of unknown dark matter and dark energy, and only 5% is

"Normal" or baryonic matter that makes up stars, planets, asteroids, humans and animals.

However, direct measurements have explained only half of the expected baryonic matter in the universe.

Yuanming Wang, female doctoral student at the School of PhysicsUniversity of Sydney, developed an original method to help find the very missing substance. She found a hitherto undetected stream of cold gas in the Milky Way about 10 light-years from Earth. The cloud is about a trillion kilometers long and 10 billion kilometers wide. Moreover, its mass is only half the moon.

The results of the study offer scientists a promising way to find the missing piece of baryonic matter in the Milky Way.

It looks like most of the "missing" baryonicmatter is in the form of clouds of cold gas either in galaxies or in between. This gas cannot be detected using conventional methods because it does not emit its own visible light and is too cold for radio astronomy.

Yuanming Wang

Astronomers looked for radio sources far away to see how they flicker. Refraction helped to understand what kind of matter light passes through.

As a result, scientists discovered five twinkling radio sources on a giant line in the sky. Analysis showed that their light passed through the same cold blob of gas.

Just as visible light is distorted whenpassing through our atmosphere, causing stars to twinkle, when radio waves pass through matter, this also affects their brightness. It is this "flicker" that scientists discovered.

Hydrogen freezes at about minus 260degrees, and theorists suggested that some of the missing baryonic matter of the Universe could be trapped in these hydrogen "snow clouds". They are almost impossible to detect directly. However, scientists have now developed a method for identifying such clumps of "invisible" cold gas using background galaxies as beacons.

The data for the search for the gas cloud was obtained with the CSIRO Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope in Western Australia.

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Radioastronomy is a branch of astronomy that studiesspace objects by studying their electromagnetic radiation in the radio wave range. The objects of radiation are practically all cosmic bodies and their complexes, as well as matter and fields that fill outer space.