{"id":676227,"date":"2026-09-07T03:06:26","date_gmt":"2026-09-07T03:06:26","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/676227\/"},"modified":"2026-09-07T03:06:26","modified_gmt":"2026-09-07T03:06:26","slug":"astronomers-confirm-einsteins-gravity-by-viewing-light-from-behind-a-supermassive-black-hole-2","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/676227\/","title":{"rendered":"Astronomers confirm Einstein\u2019s gravity by viewing light from behind a supermassive black hole"},"content":{"rendered":"<ul class=\"MuiTypography-root MuiTypography-paragraph list css-q3r3pl\" data-og-block-area=\"article-blocks\" data-og-block-nth=\"1\" data-og-block-type=\"core\/list\" data-rawhtml=\"1\">\n<li class=\"MuiTypography-root MuiTypography-body1 css-1pbbt52\">Astronomers detected delayed X-ray flashes consistent with light reflected from the far side of an accretion disk and bent around a supermassive black hole by its intense gravity.<\/li>\n<li class=\"MuiTypography-root MuiTypography-body1 css-1pbbt52\">The photons did not escape from inside the black hole. They originated outside the event horizon, where warped spacetime redirected normally hidden light into Earth\u2019s line of sight.<\/li>\n<li class=\"MuiTypography-root MuiTypography-body1 css-1pbbt52\">The observation provided direct evidence for a long-predicted general-relativistic effect and gave researchers a new way to probe the mysterious X-ray corona surrounding actively feeding black holes.<\/li>\n<\/ul>\n<p>A black hole nearly 800 million light-years away briefly revealed something that should ordinarily have been hidden from view.<\/p>\n<p>While studying powerful X-ray flares from the center of the galaxy I Zwicky 1, astronomers detected smaller flashes arriving later and at different X-ray energies. Their timing and energy shifts matched a remarkable prediction: the photons had reflected from the far side of the black hole&#8217;s accretion disk before the black hole&#8217;s gravity bent their paths around it and toward Earth.<\/p>\n<p>\u201cAny light that goes into that black hole doesn\u2019t come out, so we shouldn\u2019t be able to see anything that\u2019s behind the black hole,\u201d said Stanford astrophysicist Dan Wilkins.<\/p>\n<p>Light echoes from behind a black hole. (CREDIT: ESA) <\/p>\n<p>The explanation lies in a distinction that sounds subtle but is crucial. The detected light did not escape from inside the event horizon. Instead, it traveled through the severely <a href=\"https:\/\/www.thebrighterside.news\/post\/physicists-rewrite-einsteins-equations-to-define-spacetime-evolution\/\" rel=\"nofollow noopener\" target=\"_blank\">curved spacetime<\/a> surrounding the black hole, where gravity bent photons from otherwise hidden portions of the disk into the astronomers&#8217; line of sight.<\/p>\n<p>Two flares exposed the black hole&#8217;s hidden side<\/p>\n<p>I Zwicky 1, commonly called I Zw 1, contains an actively feeding supermassive black hole surrounded by a brilliant accretion disk.<\/p>\n<p>NuSTAR watched the object continuously for 5.3 days in January 2020, while XMM-Newton observed it during two long intervals. About 150,000 seconds into the campaign, the X-ray emission erupted in two flares lasting roughly 10,000 seconds each. At their peaks, the X-ray count rate reached about 2.5 times its earlier average.<\/p>\n<p>Those large flares were interesting but not unprecedented. What followed caught the researchers&#8217; attention.<\/p>\n<p>As each flare declined, small peaks appeared at different times in separate X-ray energy bands. The pattern appeared first among blueshifted iron-line photons and later among <a href=\"https:\/\/www.thebrighterside.news\/post\/upenn-physicists-make-light-work-of-computing\/\" rel=\"nofollow noopener\" target=\"_blank\">redshifted photons<\/a>. Statistical testing found less than a 0.01% probability that the pattern resulted from random Poisson or unrelated red-noise variations.<\/p>\n<p>The sequence matched theoretical calculations for an X-ray flare echoing across an accretion disk.<\/p>\n<p>Delayed X-ray flashes showed light from a hidden accretion disk bending around a black hole, revealing relativity in action. (CREDIT: ESA) <\/p>\n<p>\u201cI\u2019d already seen them in the theory I\u2019ve been developing, so once I saw them in the telescope observations, I could figure out the connection,\u201d Wilkins said.<\/p>\n<p>A black hole can bend light around itself<\/p>\n<p>Albert Einstein&#8217;s general theory of relativity describes gravity not simply as a force but as a curvature of spacetime produced by mass and energy.<\/p>\n<p>Near a black hole, that curvature becomes extreme. Light normally travels along the straightest available path through spacetime, but when spacetime itself is curved, those paths can appear dramatically bent to a distant observer.<\/p>\n<p>That effect allowed X-rays from the hidden far side of I Zw 1&#8217;s accretion disk to travel around the black hole rather than disappear behind it. The <a href=\"https:\/\/www.thebrighterside.news\/post\/the-physics-of-no-return-what-actually-happens-if-you-get-pulled-into-a-black-hole\/\" rel=\"nofollow noopener\" target=\"_blank\">black hole&#8217;s gravitational field<\/a> also magnified some of the radiation through gravitational lensing.<\/p>\n<p>Models had predicted such a signature decades earlier. A 1999 study of iron-line reverberation calculated how X-rays reflected from different regions of an accretion disk should arrive at different times and energies in the curved spacetime around a spinning black hole.<\/p>\n<p>The I Zw 1 observations finally exposed that behavior in actual flare data.<\/p>\n<p>Schematic of the X-ray reverberation model. (CREDIT: Dan Wilkins et al, Nature) The X-ray \u2018colors\u2019 mapped different parts of the disk<\/p>\n<p>The different energies of the delayed flashes were just as important as their timing.<\/p>\n<p>Material in the accretion disk races around the black hole at tremendous speeds. X-rays from the approaching side become blueshifted toward higher energies, while light from the receding side shifts lower. Gravity also stretches photons to lower energies, producing a gravitational redshift that becomes stronger closer to the black hole.<\/p>\n<p>These effects distort the normally narrow iron K fluorescence line emitted around 6.4 kiloelectronvolts. By following how that line changed with time, astronomers could identify which regions of the disk were responding to a flare.<\/p>\n<p>During the events, <a href=\"https:\/\/www.thebrighterside.news\/post\/galaxy-killing-wind-may-explain-why-giant-galaxies-died-so-early\/\" rel=\"nofollow noopener\" target=\"_blank\">blueshifted emission<\/a> arrived first. More redshifted photons followed later, matching light reflected from the rear portion of the disk and forced onto longer curved routes around the black hole.<\/p>\n<p>The team also measured an average iron K reverberation delay of 746 plus or minus 157 seconds.<\/p>\n<p>The flares also revealed the black hole&#8217;s corona<\/p>\n<p>The researchers had originally set out to understand something else: the black hole&#8217;s corona.<\/p>\n<p>Features of the reverberation response function detected during the X-ray flares. (CREDIT: Dan Wilkins et al, Nature) <\/p>\n<p>A corona is an extremely hot region of energetic particles close to a feeding black hole. Although its detailed structure remains uncertain, magnetic fields rising from the <a href=\"https:\/\/www.thebrighterside.news\/post\/strange-red-object-from-the-early-universe-could-be-the-first-black-hole-star\/\" rel=\"nofollow noopener\" target=\"_blank\">accretion disk<\/a> are thought to accelerate particles and produce powerful X-rays.<\/p>\n<p>Earlier observations of I Zw 1 had suggested that its corona contains a broader component spread across the inner disk and a compact, vertically extended core responsible for faster changes in brightness.<\/p>\n<p>When the corona flares, some X-rays travel directly toward Earth. Others strike the accretion disk first and are reflected, creating delayed echoes. The time between direct and reflected radiation provides a way to measure structures only a few gravitational radii from the event horizon.<\/p>\n<p>The 2020 observations showed that the brightest flares could illuminate the disk sharply enough for astronomers to resolve the unusual far-side echoes.<\/p>\n<p>General relativity became visible in the data<\/p>\n<p>The observations do not mean scientists literally photographed the back of a <a href=\"https:\/\/www.thebrighterside.news\/post\/jwst-finds-three-feeding-black-holes-packed-into-one-early-galaxy\/\" rel=\"nofollow noopener\" target=\"_blank\">black hole<\/a>. They detected a time-dependent X-ray signature that matched relativistic ray-tracing predictions for radiation coming from the disk&#8217;s hidden side.<\/p>\n<p>Alternative explanations involving changing absorption, disk ionization or ordinary continuum fluctuations had difficulty reproducing the shifting iron-line pattern.<\/p>\n<p>The soft and hard X-ray spectra of I Zw 1 obtained by XMM-Newton and NuSTAR during the 2020 observations. (CREDIT: Dan Wilkins et al, Nature) <\/p>\n<p>The result offered an unusually direct demonstration of how strongly a black hole can reshape the paths of nearby photons.<\/p>\n<p>\u201cFifty years ago, when astrophysicists started speculating about how the magnetic field might behave close to a black hole, they had no idea that one day we might have the techniques to observe this directly and see <a href=\"https:\/\/www.thebrighterside.news\/post\/groundbreaking-study-reaffirms-einstein-s-general-theory-of-relativity\/\" rel=\"nofollow noopener\" target=\"_blank\">Einstein\u2019s general theory of relativity<\/a> in action,\u201d said study co-author Roger Blandford.<\/p>\n<p>Black holes remain dark by definition. But the light surrounding them, bent, delayed and shifted by extreme gravity, can expose structures that would otherwise remain invisible.<\/p>\n<p>Dig deeper into black hole X-ray echoes<\/p>\n<p>These resources explore the X-ray reverberation, accretion-disk reflection and coronal physics behind observations of light bent around black holes.<\/p>\n<p><a href=\"https:\/\/doi.org\/10.1007\/s00159-014-0072-0\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">X-ray reverberation around accreting black holes<\/a>: Reviews how time delays between direct coronal X-rays and disk-reflected radiation can map regions only a few gravitational radii from black holes. (The Astronomy and Astrophysics Review, 2014)<\/p>\n<p>Research findings are available online in the journal <a href=\"https:\/\/www.nature.com\/articles\/s41586-021-03667-0\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">Nature<\/a>.<\/p>\n<p>Related Stories<\/p>\n","protected":false},"excerpt":{"rendered":"Astronomers detected delayed X-ray flashes consistent with light reflected from the far side of an accretion disk and&hellip;\n","protected":false},"author":2,"featured_media":676228,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[270],"tags":[63596,582,1025,3514,14588,285223,14589,18,18146,286059,286060,19,17,286061,285225,172,133,451,54118,2634,6552,286062,286063,101366,120660],"class_list":["post-676227","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-accretion-disk","tag-astronomy","tag-astrophysics","tag-black-hole","tag-cosmology","tag-dan-wilkins","tag-einstein","tag-eire","tag-general-relativity","tag-i-zw-1","tag-i-zwicky-1","tag-ie","tag-ireland","tag-light-bending","tag-nustar","tag-research","tag-science","tag-space","tag-space-news","tag-stanford-university","tag-supermassive-black-hole","tag-x-ray-echoes","tag-x-ray-reverberation","tag-x-rays","tag-xmm-newton"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/117227551826058719","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/676227","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=676227"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/676227\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/676228"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=676227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=676227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=676227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}