An international team, led by researchers at MIT\u2019s Haystack Observatory, has for the first time measured the radius of a black hole at the center of a distant galaxy \u2014 the closest distance at which matter can approach before being irretrievably pulled into a black hole, which can be billions of times more massive than our sun may reside at the heart of most galaxies. Such supermassive black holes are so powerful that activity at their boundaries can ripple throughout their host galaxies.<\/p>\n
The scientists linked together radio dishes in Hawaii, Arizona and California to create a telescope array called the \u201cEvent Horizon Telescope\u201d (EHT) that can see details 2,000 times finer than what\u2019s visible to the Hubble Space Telescope. These radio dishes were trained on M87, a galaxy some 50 million light years from the Milky Way in the Virgo Cluster (image above). M87 harbors a black hole 6 billion times more massive than our sun; using this array, the team observed the glow of matter near the edge of this black hole \u2014 a region known as the \u201cevent horizon.\u201d\u201cOnce objects fall through the event horizon, they\u2019re lost forever,\u201d says Shep Doeleman, assistant director at the MIT Haystack Observatory and research associate at the\u00a0Smithsonian Astrophysical Observatory. \u201cIt\u2019s an exit door from our universe. You walk through that door, you\u2019re not coming back.\u201d* Supermassive black holes are the most extreme objects predicted by Albert Einstein\u2019s theory of gravity \u2014 where, according to Doeleman, \u201cgravity completely goes haywire and crushes an enormous mass into an incredibly close space.\u201d<\/p>\n
At the edge of a black hole, the gravitational force is so strong that it pulls in everything from its surroundings. However, not everything can cross the event horizon to squeeze into a black hole. The result is a \u201ccosmic traffic jam\u201d in which gas and dust build up, creating a flat pancake of matter known as an accretion disk. This disk of matter orbits the black hole at nearly the speed of light, feeding the black hole a steady diet of superheated material. Over time, this disk can cause the black hole to spin in the same direction as the orbiting material.<\/p>\n
Caught up in this spiraling flow are magnetic fields, which accelerate hot material along powerful beams above the accretion disk The resulting high-speed jet, launched by the black hole and the disk, shoots out across the galaxy, extending for hundreds of thousands of light-years. These jets can influence many galactic processes, including how fast stars form.<\/p>\n
A jet\u2019s trajectory may help scientists understand the dynamics of black holes in the region where their gravity is the dominant force. Doeleman says such an extreme environment is perfect for confirming Einstein\u2019s theory of general relativity \u2014 today\u2019s definitive description of gravitation.<\/p>\n
The image above, created using computer models, shows how the extreme gravity of the black hole in M87 distorts the appearance of the jet near the event horizon. Part of the radiation from the jet is bent by gravity into a ring that is known as the \u2018shadow\u2019 of the black hole.<\/p>\n
\u201cEinstein\u2019s theories have been verified in low-gravitational field cases, like on Earth or in the solar system,\u201d Doeleman says. \u201cBut they have not been verified precisely in the only place in the universe where Einstein\u2019s theories might break down \u2014 which is right at the edge of a black hole.\u201d<\/p>\n
According to Einstein\u2019s theory, a black hole\u2019s mass and its spin determine how closely material can orbit before becoming unstable and falling in toward the event horizon. Because M87\u2019s jet is magnetically launched from this smallest orbit, astronomers can estimate the black hole\u2019s spin through careful measurement of the jet\u2019s size as it leaves the black hole.<\/p>\n
Until now, no telescope has had the magnifying power required for this kind of observation.* \u201cWe are now in a position to ask the question, \u2018Is Einstein right?\u2019\u201d Doeleman says. \u201cWe can identify features and signatures predicted by his theories, in this very strong gravitational field.\u201d<\/p>\n
The team used a technique called Very Long Baseline Interferometry, or VLBI, which links data from radio dishes located thousands of miles apart. Signals from the various dishes, taken together, create a \u201cvirtual telescope\u201d with the resolving power of a single telescope as big as the space between the disparate dishes. The technique enables scientists to view extremely precise details in faraway galaxies.<\/p>\n
Using the technique, Doeleman and his team measured the innermost orbit of the accretion disk to be only 5.5 times the size of the black hole event horizon. According to the laws of physics, this size suggests that the accretion disk is spinning in the same direction as the black hole \u2014 the first direct observation to confirm theories of how black holes power jets from the centers of galaxies.<\/p>\n
The team plans to expand its telescope array, adding radio dishes in Chile, Europe, Mexico, Greenland and Antarctica, in order to obtain even more detailed pictures of black holes in the future.<\/p>\n
Christopher Reynolds, a professor of astronomy at the University of Maryland, says the group\u2019s results provide the first observational data that will help scientists understand how a black hole\u2019s jets behave. \u201cThe basic nature of jets is still mysterious,\u201d Reynolds says. \u201cMany astrophysicists suspect that jets are powered by black hole spin \u2026 but right now, these ideas are still entirely in the realm of theory. This measurement is the first step in putting these ideas on a firm observational basis.\u201d<\/p>\n
The image below, from the jet is bent by gravity into a ring that is known as the \u2018shadow\u2019 of the black hole.<\/p>\n
Source: Sheperd S. Doeleman et al., Jet-Launching Structure Resolved Near the Supermassive Black Hole in M87, Science, 2012, DOI: 10.1126\/science.1224768<\/p>\n
The Daily Galaxy via\u00a0Science,\u00a0The Perimeter Institute, and\u00a0University of Waterloo<\/p>\n
Image credits: Avery E. Broderick, Perimeter Institute & University of Waterloo<\/p>\n
Credits to the source<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
\u201cThe Exit Door from Our Universe\u201d An international team, led by researchers at MIT\u2019s Haystack Observatory, has for the first time measured the radius of a black hole at the center of a distant galaxy \u2014 the closest distance at which matter can approach before being irretrievably pulled into a black hole, which can be […]<\/p>\n","protected":false},"author":487,"featured_media":50,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,3,4,5,6,7,8],"tags":[41,42,43,44,45,46],"class_list":["post-7","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-empower-network","category-entertainment","category-healthy-lifestyle","category-sci-fi-news","category-success-tools","category-testimonials","category-world-news","tag-black-hole","tag-einstein","tag-event-horizon","tag-gravity","tag-jets","tag-telescope"],"_links":{"self":[{"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/posts\/7","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/users\/487"}],"replies":[{"embeddable":true,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/comments?post=7"}],"version-history":[{"count":2,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/posts\/7\/revisions"}],"predecessor-version":[{"id":65,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/posts\/7\/revisions\/65"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/media\/50"}],"wp:attachment":[{"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/media?parent=7"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/categories?post=7"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/empowernetwork.com\/sandeep254\/wp-json\/wp\/v2\/tags?post=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}