Mysterious Clouds May Offer New Clues About Dark Matter

Researchers are using powerful instruments, which detect gravitational waves billions of light-years away, to locate possible boson clouds – they would be a likely source of dark matter, which accounts for about 85 percent of all matter in the universe.

A new international study developed by the LIGO-Virgo-KAGRA collaboration and co-led by researchers at the Australian National University (ANU) is using powerful instruments and tools to attempt to detect gravitational waves deep in the cosmos. The gravitational waves would be caused by boson clouds that surround the black holes: there the enigmatic dark matter could finally be revealed.

Different theories have established that gravitational waves, space-time fluctuations caused by cataclysms and great cosmic events, could be the key to discovering dark matter. Dark matter cannot be seen, but nevertheless scientists know that it exists and that it represents more than 85% of all the matter present in the universe due to the influence it exerts on other bodies and objects.

The fundamental forces of the universe
In this framework of uncertainties to reveal, one of the possibilities is that the dark matter is “hidden” between the so-called boson clouds. Bosons are the elementary subatomic particles, which exert the fundamental forces of the cosmos. In other words, they do not compose visible matter but they do carry out the four basic interactions that, from the quantum world, govern the behavior of the universe: gravity, electromagnetism, the weak nuclear force and the strong nuclear force.

According to a press release, scientists believe that some extremely fast spinning black holes trap large numbers of bosons in their powerful gravitational field, creating a spinning cloud with them. These boson clouds create a delicate dance that goes on for millions of years, continually generating gravitational waves that rush through space.

As they establish in the new study, recently published in arXiv, the use of instruments such as the Gravitational Wave Observatory with Laser Interferometer (LIGO) and others can allow them to identify these gravitational waves and, from them, finally reach the elusive dark matter.

Looking for the youngest clouds
Apparently, the discovery of boson clouds goes hand in hand with their age. The strength of any gravitational wave depends on the age of the cloud: older ones send weaker signals. The astronomers explained that the boson cloud shrinks as it loses energy by sending out gravitational waves. Consequently, they think they could find boson clouds somewhere in the Milky Way itself.

The researchers highlighted that the discoveries of gravitational waves not only provide information about mysterious compact objects in the universe, such as black holes and neutron stars, but also allow the identification of subatomic particles such as those that make up boson clouds. and they could reveal dark matter.

All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data. The LIGO Scientific Collaboration, the Virgo Collaboration and the KAGRA Collaboration. arXiv (2021).