{"id":33848,"date":"2022-07-06T07:39:32","date_gmt":"2022-07-06T07:39:32","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=110147"},"modified":"2022-07-06T08:07:12","modified_gmt":"2022-07-06T08:07:12","slug":"astronomers-are-making-maps-using-black-hole-echoes","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/astronomers-are-making-maps-using-black-hole-echoes\/","title":{"rendered":"Astronomers are making maps using black hole echoes"},"content":{"rendered":"

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By Ezzy Pearson\n \t\t<\/p>

Published: Wednesday, 06 July 2022 at 12:00 am<\/p>

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As the team behind the recent image of the black hole at the centre of our Galaxy<\/a> know only too well, investigating black holes is incredibly difficult because they are exactly that \u2013 black.<\/p>\n

The Event Horizon Telescope team managed it using a planet-sized telescope, but in the meantime, another team has been using a more unusual method \u2013 echolocation.<\/p>\n

The Milky Way is home to tens of millions of black holes<\/a>, left behind by supernovae<\/a>.<\/p>\n

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The first ever image captured of Sagittarius A*, the supermassive black hole at the centre of our Galaxy. Credit: EHT Collaboration<\/span><\/figcaption><\/div>\n

Most of the time they are invisible until they feast on the gas around them, creating a burst of X-rays.\u00a0This then bounces and echoes off the surrounding gas, illuminating it.<\/p>\n

A team of astronomers from MIT has tracked down a total of 10 echoing black holes \u2013 8 of which were new discoveries \u2013 and watched them for several months.<\/p>\n

\u201cThese black holes range in mass from 5 to 15 times the mass of the Sun, and they\u2019re all in binary systems with normal, low-mass, Sun-like stars,\u201d says Jingyi Wang from MIT, who led the study.<\/p>\n

By comparing the delay in light from the black hole\u2019s corona arriving at Earth to the arrival of echo, the team was able to create a map of gas around the black hole.<\/span><\/p>\n

This revealed that the black holes initially go through a \u2018hard\u2019 stage lasting a few weeks, where they form coronas of high-energy photons and shoot out jets of material at near light speeds.<\/p>\n

The jets and corona first begin to sputter, before transitioning back to a low-energy \u2018soft\u2019 phase.<\/p>\n

MIT\u2019s Erin Kara works with MIT education and music scholars Kyle Keane and Ian Condry to convert the echoes into sound waves. Hear them in the video below.<\/strong><\/em><\/p>\n