Scientists detect evidence that gravitational waves fill the cosmos

Scientists have announced the first evidence of a universal background of gravitational waves that permeates the cosmos. These gravitational waves, ripples in the fabric of the universe, are believed to have been generated over immense periods by the intricate dance of supermassive black holes, each weighing billions of times the mass of our Sun, as they gradually spiral towards one another and eventually merge.

The detection of this gravitational wave background, described as akin to hearing a collective murmur of conversation at a bustling party without discerning any individual voice, presents a remarkable opportunity for scientists to deepen their understanding of the origins and behaviour of these elusive cosmic phenomena.

By studying the properties and propagation of these background ripples, researchers hope to gain insights into the mechanisms behind gravitational wave production and unravel the mysteries surrounding supermassive black hole mergers - a process that can persist for millions of years and profoundly influence the evolution of galaxies.

The evidence was presented by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) Physics Frontiers Center in a series of papers published in the Astrophysical Journal Letters. NANOGrav, a collaborative effort comprising over 190 scientists from the United States and Canada, including experts from NASA's Jet Propulsion Laboratory and other NASA centres, operates as a Physics Frontiers Center funded by the National Science Foundation.

Over the course of more than 15 years, the collaboration meticulously 15 years of data from three radio observatories - Arecibo Observatory in Puerto Rico, the Green Bank Telescope in West Virginia and the Very Large Array in New Mexico - in its quest to detect these elusive gravitational waves.

"It's incredibly exciting to have helped open a new window to the Universe," said SETI Institute researcher Dr Michael Lam, one of the team members.

Congratulations to NANOGrav for detecting evidence that gravitational waves fill the cosmos. These ripples in the fabric of space happen when massive objects like black holes circle one another before colliding. The result brings us closer to understanding how galaxies evolve.… pic.twitter.com/AuXBgkZkb7

— NASA (@NASA) June 29, 2023

This groundbreaking discovery complements the landmark detection of gravitational waves in 2015 by the Laser Interferometer Gravitational Observatory (LIGO). However, the gravitational waves detected by NANOGrav possess a significantly longer wavelength compared to those observed by LIGO. The 2015 LIGO detections originated from black holes approximately 30 times the mass of our Sun.

As scientists continue to unravel the secrets of these cosmic ripples, they pave the way for a new era of gravitational wave astronomy, offering profound insights into the fundamental nature of the universe and its evolution over time.