Scientists are reporting, in a series of papers in The Astrophysical Journal Letters (and in an announcement on June 29, 2023—see video below), the first evidence that our Earth and the universe around us are awash in a background of gravitational waves.
The 15 years worth of observations by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) suggest that these waves may be produced by supermassive black holes merging across the universe. Or they may also have other origins, such as leftover ripples in space-time created shortly after the big bang.
"The effect of the gravitational waves on the pulsars is extremely weak and hard to detect, but we built confidence in the findings over time as we collected more data," says Katerina Chatziioannou, a NANOGrav team member and an assistant professor of physics at Caltech.
Citation: Gabriella Agazie et al. The NANOGrav 15 yr Data Set: Evidence for a Gravitational-wave Background. 2023 June 29 © 2023. Published by the American Astronomical Society. The Astrophysical Journal Letters, Volume 951, Number 1Focus on NANOGrav's 15 yr Data Set and the Gravitational Wave Background https://iopscience.iop.org/article/10.3847/2041-8213/acdac6 (open access)