'A New Precision Tool for Physics': Dark Matter Could be Illuminated Using LIGO

Dark matter is a mysterious substance, the existence of which some say is merely rumored — it's existence was first formally hypothesized in academia in 1922, although the phrase and concept had abounded on a purely speculative basis for some time prior. Today, NASA suggests up to 85 percent of the matter in the known universe could be of the dark variety, with planets, nebulae and other objects in space made of conventional matter accounting for the remainder.

The issue some have with the dark matter proposition is that it does not interact with light, and is thus invisible. Astronomers claim to have observed the phenomenon, saying it reveals itself via its gravitational effects — galaxies rotate far too rapidly to be held together purely by the gravitational pull of their visible matter, and dark matter would explain this discrepancy. However, conclusive proof has remained irritatingly elusive — until now, perhaps.

A team of Stanford University researchers in the US, led by Asimina Arvanitaki at the Perimeter Institute in Canada, believe the question about whether the universe is truly made of dark matter can be resolved using Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors, instruments that made history in 2016, when they were used to detect gravitational waves for the first time.

"In the next few years, Advanced LIGO may see gravitational waves from thousands of black hole mergers. This marks the beginning of a new precision tool for physics," Arvanitaki wrote in a published study.

Moreover, they believe dark matter is comprised of particles called axions — and if the researchers are correct, dark matter can be detected through gravitational waves, as axions accelerated by a black hole would emit them, just as electrons give off electromagnetic waves.

LIGO in its current form is not sensitive enough to detect the kind of gravitational waves that may be emitted off by axions, but as instruments improve and fine-tune, the team believes they may be able to see as many as thousands of axion signals coming in a single day. Axions are predicted to weigh around 1 quintillion (a billion billion) times less than an electron — if their existence is proven, these superlight particles could solve some major theoretical problems with the standard model of physics, and elucidate a number of otherwise puzzling astronomical observations.

Moreover, it's possible axions may be found on Earth. Currently, a number of experiments, both terrestrial and extraterrestrial, are attempting to determine the composition of the intangible matter.

The study follows news astronomers have developed a way to detect the ultraviolet background of the universe, a discovery that may help explain why there are so few small galaxies in the cosmos, solving the enduring "dwarf galaxy dilemma" in the process. According to cosmological simulations, there should far more small galaxies in the universe than the ones currently observable by mankind.