{"id":283652,"date":"2025-11-14T09:29:10","date_gmt":"2025-11-14T09:29:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/283652\/"},"modified":"2025-11-14T09:29:10","modified_gmt":"2025-11-14T09:29:10","slug":"could-black-hole-shadows-reveal-new-theories-of-gravity","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/283652\/","title":{"rendered":"Could black hole shadows reveal new theories of gravity?"},"content":{"rendered":"

\"StriatedThis image, which the European Southern Observatory (ESO<\/a>) released on March 27, 2024, shows the supermassive black hole<\/a> at the center of our Milky Way<\/a> in polarized light<\/a>. It depicts the accretion disk<\/a> of hot material surrounding the event horizon. We can\u2019t see the black hole itself in the center. A new study shows how astronomers could use black hole shadows<\/a> to test alternative theories of gravity. Image via EHT Collaboration\/ ESO<\/a>.<\/p>\n

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A research team has developed a new method for testing whether black holes follow Albert Einstein\u2019s theory of general relativity or one of the many alternative theories of gravity.
\nImages of black holes could provide a testing ground for these alternate theories of gravity.
\nThe researchers used simulations to come up with measurable criteria that they can use to test these alternate theories in the future using more advanced telescopes.<\/p>\n

Could black hole shadows reveal new theories of gravity?<\/p>\n

A black hole<\/a> is a region of space where gravity is so strong that nothing, not even light, can escape. Astronomers captured the first image<\/a> of a black hole \u2013 or, technically, the light from the accretion disk<\/a> around it \u2013 in 2019. On November 5, 2025, an international team of researchers said<\/a> it could be possible to use images of black hole shadows to test the different theories on how black holes are created. Using future telescopes with even sharper images than we have now, astronomers believe they could determine whether all black holes behave according to Einstein\u2019s theory of relativity<\/a> or if other theories of gravity could be possible.<\/p>\n

The researchers conducted highly complex simulations to test the various scenarios. If they could ever prove that some black holes operate on different theories of gravity, it would be a groundbreaking moment in astrophysics.<\/p>\n

The intriguing peer-reviewed<\/a> results were published<\/a> in Nature Astronomy on November 5, 2025. There is also a non-paywalled preprint version of the paper available on arXiv<\/a>.<\/p>\n

High-resolution images of black hole shadows are enabling scientists to test Einstein\u2019s theory of relativity against alternative models, with future observations expected to distinguish between competing theories.<\/p>\n

\u2014 Science X \/ Phys.org (@sciencex.bsky.social)<\/a> 2025-11-05T05:00:34-05:00<\/a><\/p>\n

Black hole shadows<\/p>\n

The study focuses on the \u201cshadows\u201d of black holes. Another name for this region is the event horizon shadow<\/a>. The event horizon<\/a> itself is the boundary around a black hole from which light cannot escape. And the event horizon shadow is about twice as large as the event horizon. This shadow captures any light passing through it, trapping it. The event horizon shadow also distorts space-time<\/a> \u2013 a concept that recognizes the union of space and time<\/a> \u2013 around the black hole. So both of these effects together create a \u201cdark zone\u201d that is about twice as large as the black hole itself.<\/p>\n

Images that astronomers have obtained so far of black holes don\u2019t show the black hole itself. But they do show the shadow region and accretion disk of hot material that surrounds it (which is what we see in the images). By studying the accretion disk of visible material, astronomers can learn more about the shadow region and black holes in general. As Luciano Rezzolla<\/a> at Goethe University Frankfurt in Germany, who led the new research, explained<\/a>:<\/p>\n

What you see on these images is not the black hole itself, but rather the hot matter in its immediate vicinity. As long as the matter is still rotating outside the event horizon \u2013 before being inevitably pulled in \u2013 it can emit final signals of light that we can, in principle, detect.<\/p>\n

\"6Depiction of how \u201cnon-Einstein\u201d alternative theories of gravity<\/a> (bottom row) could produce black holes that look similar to known black holes (top row). Image via Luciano Rezzolla\/ Goethe University\/ EurekAlert!<\/a>.
\nEinstein\u2019s theory of relativity<\/p>\n

What we know about black holes so far fits with Einstein\u2019s theory of relativity. Indeed, it considers the existence of black holes to be \u201cspecial solutions.\u201d The theory can account for all the bizarre characteristics of black holes, even the utterly strange event horizon.<\/p>\n

But is it possible that other theories of gravity could also produce black holes? The researchers in the new study think it\u2019s possible. Rezzolla said:<\/p>\n

There are, however, also other, still hypothetical theories that likewise predict the existence of black holes. Some of these approaches require the presence of matter with very specific properties or even the violation of the physical laws we currently know.<\/p>\n

\"BaldLuciano Rezzolla<\/a> at Goethe University Frankfurt in Germany led the new study about black holes and alternative theories of gravity. Image via Goethe University Frankfurt<\/a>.
\nImages of black hole shadows to test theories of gravity<\/p>\n

Researchers want to test the theories of gravity using shadow images of supermassive black holes. These are gargantuan black holes that reside in the centers of galaxies, including our own Milky Way. To do so, scientists need two things, as Rezolla explained:<\/p>\n

This requires two things. On the one hand, high-resolution shadow images of black holes to determine their radius as accurately as possible, and on the other hand, a theoretical description of how strongly the various approaches deviate from Einstein\u2019s theory of relativity.<\/p>\n

\"SmilingAkhil Uniyal<\/a> at the Tsung-Dao Lee Institute in China is the lead author of the new paper about black holes and alternative theories of gravity. Image via ResearchGate<\/a>.
\nComplex simulations of black holes<\/p>\n

The researchers used highly complex computer simulations to test various other hypothetical types of black holes. They wanted to see how similar, or different, those black holes would be from ones associated with Einstein\u2019s theory of relativity. The simulations replicated the behavior of matter and magnetic fields in the curved space-time surrounding black holes. Lead author Akhil Uniyal<\/a> at the Tsung-Dao Lee Institute in China said:<\/p>\n

The central question was: How significantly do images of black holes differ across various theories?<\/p>\n

Future telescopes could provide answers<\/p>\n

The simulations don\u2019t provide a final answer. But they do establish the necessary criteria that future telescopes can use to obtain even higher resolution images than the ones we have now from the Event Horizon Telescope (EHT<\/a>). Those images could help support \u2013 or refute \u2013 alternative theories of gravity being involved in the creation of black holes. The Event Horizon Telescope has, of course, been essential in our ability to \u201csee\u201d black holes as clearly as we can to date. As Rezzolla noted:<\/p>\n

One of the EHT collaboration\u2019s most important contributions to astrophysics is turning black holes into testable objects. Our expectation is that relativity theory will continue to prove itself, just as it has time and again up to now. Even the established theory must be continuously tested, especially with extreme objects like black holes.<\/p>\n

So far, the observations of black holes have been consistent with Einstein\u2019s theory of relativity. But it will be interesting to see what future observations reveal. Will they hold any surprises?<\/p>\n

Bottom line: A new international study proposes how astronomers could use future improved images of black hole shadows to test alternative theories of gravity.<\/p>\n

Source: The future ability to test theories of gravity with black-hole shadows<\/a><\/p>\n

Source (preprint): The future ability to test theories of gravity with black-hole shadows<\/a><\/p>\n

Via Goethe University Frankfurt<\/a><\/p>\n

Read more: How dark matter in exoplanets could create new black holes<\/a><\/p>\n

Read more: Little Red Dots might indicate ancient, growing black holes<\/a><\/p>\n

Paul Scott Anderson
\n View Articles<\/a><\/p>\n

About the Author:<\/p>\n

Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan\u2019s Cosmos. He studied English, writing, art and computer\/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
\n
\nWhile interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
\n
\nHe has been writing for EarthSky since 2018, and also assists with proofing and social media.<\/p>\n","protected":false},"excerpt":{"rendered":"This image, which the European Southern Observatory (ESO) released on March 27, 2024, shows the supermassive black hole…\n","protected":false},"author":2,"featured_media":283653,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[64,63,163827,3189,292,128,285,25642],"class_list":{"0":"post-283652","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-au","9":"tag-australia","10":"tag-black-hole-shadows","11":"tag-gravity","12":"tag-physics","13":"tag-science","14":"tag-space","15":"tag-theory-of-relativity"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/283652","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=283652"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/283652\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/283653"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=283652"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=283652"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=283652"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}