By: SPACE.com Staff
Published: 02/09/2012 01:34 PM EST on SPACE.com
The gigantic black hole at the heart of our Milky Way galaxy may be devouring asteroids on a daily basis, a new study suggests.
For several years, NASA's Chandra spacecraft has detected X-ray flares about once a day coming from our galaxy's central black hole, which is known as Sagittarius A* (Sgr A* for short). These flares may be caused by asteroids falling into the supermassive black hole's maw, according to the study.
"People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole," study lead author Kastytis Zubovas, of the University of Leicester in the United Kingdom, said in a statement. "It's exciting because our study suggests that a huge number of them are needed to produce these flares."
Asteroids circling a black hole
Zubovas and his colleagues suggest that a cloud around Sgr A* contains trillions of asteroids and comets that the black hole stripped from their parent stars.
Asteroids passing within about 100 million miles (160 million kilometers) of the black hole — roughly the distance between the Earth and the sun — are likely torn to pieces by Sgr A*'s gravity, according to the study. [Photos: Black Holes of the Universe]
These fragments would be vaporized by friction as they encounter the hot gas flowing onto the black hole, much as meteors are burned up by the gases in Earth's atmosphere. This vaporization likely spawns the X-ray flares, which last for a few hours and range in brightness from a few times to nearly 100 times that of the black hole's regular output, researchers said.
Sgr A* then swallows up what's left of the close-flying asteroid.
"An asteroid's orbit can change if it ventures too close to a star or planet near Sgr A*," said co-author Sergei Nayakshin, also of the University of Leicester. "If it's thrown toward the black hole, it's doomed."
It would take an asteroid at least 6 miles (10 km) wide to generate the flares seen by Chandra, the researchers estimate. The black hole may also be consuming smaller space rocks, but the resulting flares would likely be too faint to observe.
The new study is in rough agreement with previous modeling work, which has estimated that trillions of asteroids are likely to surround the Milky Way's central black hole.
"As a reality check, we worked out that a few trillion asteroids should have been removed by the black hole over the 10-billion-year lifetime of the galaxy," said co-author Sera Markoff of the University
of Amsterdam in the Netherlands. "Only a small fraction of the total would have been consumed, so the supply of asteroids would hardly be depleted."
Sgr A* is probably also devouring planets that stray too close, causing much more powerful X-ray flares than those analyzed in the new study. Such dramatic events are likely rare, since planets are not nearly as common as asteroids, researchers said.
However, scientists may have observed the aftermath of the Milky Way's black hole gobbling up a planet. About 100 years ago, the X-ray output of Sgr A* brightened by a factor of a million. While this event happened before the existence of X-ray telescopes, Chandra and other instruments have seen
evidence of an X-ray "echo" reflecting off nearby clouds, researchers said.
The researchers report their results in the Monthly Notices of the Royal Astronomical Society.
Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.
Copyright 2012 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Our 2024 Coverage Needs You
It's Another Trump-Biden Showdown — And We Need Your Help
The Future Of Democracy Is At Stake
Our 2024 Coverage Needs You
Your Loyalty Means The World To Us
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
The 2024 election is heating up, and women's rights, health care, voting rights, and the very future of democracy are all at stake. Donald Trump will face Joe Biden in the most consequential vote of our time. And HuffPost will be there, covering every twist and turn. America's future hangs in the balance. Would you consider contributing to support our journalism and keep it free for all during this critical season?
HuffPost believes news should be accessible to everyone, regardless of their ability to pay for it. We rely on readers like you to help fund our work. Any contribution you can make — even as little as $2 — goes directly toward supporting the impactful journalism that we will continue to produce this year. Thank you for being part of our story.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
It's official: Donald Trump will face Joe Biden this fall in the presidential election. As we face the most consequential presidential election of our time, HuffPost is committed to bringing you up-to-date, accurate news about the 2024 race. While other outlets have retreated behind paywalls, you can trust our news will stay free.
But we can't do it without your help. Reader funding is one of the key ways we support our newsroom. Would you consider making a donation to help fund our news during this critical time? Your contributions are vital to supporting a free press.
Contribute as little as $2 to keep our journalism free and accessible to all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. Would you consider becoming a regular HuffPost contributor?
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. If circumstances have changed since you last contributed, we hope you'll consider contributing to HuffPost once more.
Support HuffPostAlready contributed? Log in to hide these messages.