{"id":17281,"date":"2023-06-28T22:56:27","date_gmt":"2023-06-28T14:56:27","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/astrophysicists-report-solid-evidence-for-a-background-hum-of-gravitational-waves\/"},"modified":"2023-06-28T22:56:27","modified_gmt":"2023-06-28T14:56:27","slug":"astrophysicists-report-solid-evidence-for-a-background-hum-of-gravitational-waves","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/astrophysicists-report-solid-evidence-for-a-background-hum-of-gravitational-waves\/","title":{"rendered":"Astrophysicists report solid evidence for a background hum of gravitational waves"},"content":{"rendered":"
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Scientists monitor how ripples in spacetime, most likely caused by the interaction of supermassive black holes, affect the timing of signals from pulsars. (Illustration by Aurore Simonnet for NANOGrav Collaboration)<\/figcaption><\/figure>\n

Astrophysicists have found the best evidence yet for a low-frequency \u201chum\u201d of gravitational waves rippling through the cosmos, based on 15 years\u2019 worth of ultra-precise measurements checking the timing of radio pulses from distant stars.<\/p>\n

The evidence, newly published in the Astrophysical Journal Letters, comes from several teams of researchers working in the U.S. and Canada as well as Europe, India, Australia and China.<\/p>\n

The teams monitored radio emissions from a total of 115 ultra-dense, spinning stars known as pulsars. Nearly 70 of those pulsars were observed by the North American Nanohertz Observatory for Gravitational Waves, known as NANOGrav.<\/p>\n

\u201cThis is key evidence for gravitational waves at very low frequencies,\u201d Vanderbilt University\u2019s Stephen Taylor, who co-led the search and is the current chair of the NANOGrav Collaboration, said today in a news release. \u201cAfter years of work, NANOGrav is opening an entirely new window on the gravitational-wave universe.\u201d<\/p>\n

The NANOGrav Collaboration has more than 170 members, including researchers from the University of Washington at Bothell, Oregon State University and the University of British Columbia. Jeff Hazboun, a physics professor at Oregon State who previously served as a postdoctoral researcher at UW-Bothell, said working on NANOGrav has been \u201creally wonderful.\u201d<\/p>\n

\u201cI\u2019d definitely say that big problems nowadays really require a lot of people to work on them, and collaborations are a great way to get things done,\u201d he told GeekWire. \u201cYou know, we were using Zoom two years before the pandemic.\u201d<\/p>\n

Hazboun said his primary role is to \u201cmake sure that what we\u2019re seeing is what we think we\u2019re seeing, and understanding how sensitive our array of pulsars is as a detector for gravitational waves.\u201d<\/p>\n

A detector of galactic proportions<\/h4>\n

Pulsars send out radio waves in a rotating beam as the stars spin \u2014somewhat like the rotating spotlight in a lighthouse. The fastest-spinning pulsars rotate hundreds of times a second, which means they can serve as ultra-precise cosmic clocks.<\/p>\n

In the mid-1990s, scientists figured out that the timing of the radio flashes from pulsars could theoretically be used to detect gravitational waves created by powerful phenomena such as the interactions between two supermassive black holes.<\/p>\n

Such waves should create subtle ripples of distortion in the fabric of spacetime, in accordance with Albert Einstein\u2019s theory of general relativity. To observers on Earth, it would look as if the timing of the radio pulses was thrown off ever so slightly.<\/p>\n

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