{"id":16812,"date":"2019-09-12T10:45:21","date_gmt":"2019-09-12T10:45:21","guid":{"rendered":"https:\/\/www.revoscience.com\/en\/?p=16812"},"modified":"2020-06-09T12:41:38","modified_gmt":"2020-06-09T12:41:38","slug":"scientists-detect-the-ringing-of-a-newborn-black-hole-for-the-first-time","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/scientists-detect-the-ringing-of-a-newborn-black-hole-for-the-first-time\/","title":{"rendered":"Scientists detect the ringing of a newborn black hole for the first time"},"content":{"rendered":"\n

Results support Einstein\u2019s theory and the idea that black holes have no \u201chair.\u201d<\/em><\/strong><\/p>\n\n\n\n

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If Albert Einstein\u2019s theory of general relativity holds true, then a black hole, born from the cosmically quaking collisions of two massive black holes, should itself \u201cring\u201d in the aftermath, producing gravitational waves much like a struck bell reverbates sound waves. Einstein predicted that the particular pitch and decay of these gravitational waves should be a direct signature of the newly formed black hole\u2019s mass and spin.<\/p>\n\n\n\n

Now, physicists from MIT and elsewhere have \u201cheard\u201d the ringing of an infant black hole for the first time, and found that the pattern of this ringing does, in fact, predict the black hole\u2019s mass and spin \u2014 more evidence that Einstein was right all along.<\/p>\n\n\n\n

The findings, published today in\u00a0Physical Review Letters<\/em>, also favor the idea that black holes lack any sort of \u201chair\u201d \u2014 a metaphor referring to the idea that black holes, according to Einstein\u2019s theory, should exhibit just three observable properties: mass, spin, and electric charge. All other characteristics, which the physicist John Wheeler termed \u201chair,\u201d should be swallowed up by the black hole itself, and would therefore be unobservable.<\/p>\n\n\n\n

The team\u2019s findings today support the idea that black holes are, in fact, hairless. The researchers were able to identify the pattern of a black hole\u2019s ringing, and, using Einstein\u2019s equations, calculated the mass and spin that the black hole should have, given its ringing pattern. These calculations matched measurements of the black hole\u2019s mass and spin made previously by others.<\/p>\n\n\n\n

If the team\u2019s calculations deviated significantly from the measurements, it would have suggested that the black hole\u2019s ringing encodes properties other than mass, spin, and electric charge \u2014 tantalizing evidence of physics beyond what Einstein\u2019s theory can explain. But as it turns out, the black hole\u2019s ringing pattern is a direct signature of its mass and spin, giving support to the notion that black holes are bald-faced giants, lacking any extraneous, hair-like properties.<\/p>\n\n\n\n

\u201cWe all expect general relativity to be correct, but this is the first time we have confirmed it in this way,\u201d says the study\u2019s lead author, Maximiliano Isi, a NASA Einstein Fellow in MIT\u2019s Kavli Institute for Astrophysics and Space Research. \u201cThis is the first experimental measurement that succeeds in directly testing the no-hair theorem. It doesn\u2019t mean black holes couldn\u2019t have hair. It means the picture of black holes with no hair lives for one more day.\u201d<\/p>\n\n\n\n

A chirp, decoded<\/strong><\/p>\n\n\n\n

On Sept. 9, 2015, scientists made the\u00a0first-ever detection<\/a>\u00a0of gravitational waves \u2014 infinitesimal ripples in space-time, emanating from distant, violent cosmic phenomena. The detection, named GW150914, was made by LIGO, the Laser Interferometer Gravitational-wave Observatory. Once scientists cleared away the noise and zoomed in on the signal, they observed a waveform that quickly crescendoed before fading away. When they translated the signal into sound, they heard something resembling a \u201cchirp.\u201d<\/p>\n\n\n\n

Scientists determined that the gravitational waves were set off by the rapid inspiraling of two massive black holes. The peak of the signal \u2014 the loudest part of the chirp \u2014 linked to the very moment when the black holes collided, merging into a single, new black hole. While this infant black hole likely gave off gravitational waves of its own, its signature ringing, physicists assumed, would be too faint to decipher amid the clamor of the initial collision.<\/p>\n\n\n\n

Isi and his colleagues, however, found a way to extract the black hole\u2019s reverberation from the moments immediately after the signal\u2019s peak. In previous work led by Isi\u2019s co-author, Matthew Giesler, the team showed through simulations that such a signal, and particularly the portion right after the peak, contains \u201covertones\u201d \u2014 a family of loud, short-lived tones. When they reanalyzed the signal, taking overtones into account, the researchers discovered that they could successfully isolate a ringing pattern that was specific to a newly formed black hole.<\/p>\n\n\n\n

In the team\u2019s new paper, the researchers applied this technique to actual data from the GW150914 detection, concentrating on the last few milliseconds of the signal, immediately following the chirp\u2019s peak. Taking into account the signal\u2019s overtones, they were able to discern a ringing coming from the new, infant black hole. Specifically, they identified two distinct tones, each with a pitch and decay rate that they were able to measure.<\/p>\n\n\n\n

\u201cWe detect an overall gravitational wave signal that\u2019s made up of multiple frequencies, which fade away at different rates, like the different pitches that make up a sound,\u201d Isi says. \u201cEach frequency or tone corresponds to a vibrational frequency of the new black hole.\u201d<\/p>\n\n\n\n

Listening beyond Einstein<\/strong><\/p>\n\n\n\n

Einstein\u2019s theory of general relativity predicts that the pitch and decay of a black hole\u2019s gravitational waves should be a direct product of its mass and spin. That is, a black hole of a given mass and spin can only produce tones of a certain pitch and decay. As a test of Einstein\u2019s theory, the team used the equations of general relativity to calculate the newly formed black hole\u2019s mass and spin, given the pitch and decay of the two tones they detected.<\/p>\n\n\n\n

They found their calculations matched with measurements of the black hole\u2019s mass and spin previously made by others. Isi says the results demonstrate that researchers can, in fact, use the very loudest, most detectable parts of a gravitational wave signal to discern a new black hole\u2019s ringing, where before, scientists assumed that this ringing could only be detected within the much fainter end of the gravitational wave signal, and only with much more sensitive instruments than what currently exist.<\/p>\n\n\n\n

\u201cThis is exciting for the community because it shows these kinds of studies are possible now, not in 20 years,\u201d Isi says.<\/p>\n\n\n\n

As LIGO improves its resolution, and more sensitive instruments come online in the future, researchers will be able to use the group\u2019s methods to \u201chear\u201d the ringing of other newly born black holes. And if they happen to pick up tones that don\u2019t quite match up with Einstein\u2019s predictions, that could be an even more exciting prospect.<\/p>\n\n\n\n

\u201cIn the future, we\u2019ll have better detectors on Earth and in space, and will be able to see not just two, but tens of modes, and pin down their properties precisely,\u201d Isi says. \u201cIf these are not black holes as Einstein predicts, if they are more exotic objects like wormholes or boson stars, they may not ring in the same way, and we\u2019ll have a chance of seeing them.\u201d<\/p>\n\n\n\n

This research was supported, in part, by NASA, the Sherman Fairchild Foundation, the Simons Foundation, and the National Science Foundation.<\/p>\n
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Results support Einstein\u2019s theory and the idea that black holes have no \u201chair.\u201d<\/p>\n","protected":false},"author":2,"featured_media":16813,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"class_list":["post-16812","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research"],"featured_image_urls":{"full":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",1920,1080,false],"thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-200x200.jpg",200,200,true],"medium":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-300x169.jpg",300,169,true],"medium_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-768x432.jpg",750,422,true],"large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-1024x576.jpg",750,422,true],"1536x1536":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",1536,864,false],"2048x2048":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",1920,1080,false],"ultp_layout_landscape_large":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",1200,675,false],"ultp_layout_landscape":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",870,489,false],"ultp_layout_portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",600,338,false],"ultp_layout_square":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",600,338,false],"newspaper-x-single-post":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-760x490.jpg",760,490,true],"newspaper-x-recent-post-big":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-550x360.jpg",550,360,true],"newspaper-x-recent-post-list-image":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1-95x65.jpg",95,65,true],"web-stories-poster-portrait":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",640,360,false],"web-stories-publisher-logo":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",96,54,false],"web-stories-thumbnail":["https:\/\/www.revoscience.com\/en\/wp-content\/uploads\/2019\/09\/black-hole1.jpg",150,84,false]},"author_info":{"info":["RevoScience"]},"category_info":"Research<\/a>","tag_info":"Research","comment_count":"0","_links":{"self":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/16812","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/comments?post=16812"}],"version-history":[{"count":0,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/posts\/16812\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media\/16813"}],"wp:attachment":[{"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/media?parent=16812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/categories?post=16812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.revoscience.com\/en\/wp-json\/wp\/v2\/tags?post=16812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}