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Chandra image of Sgr A* Image Credit – NASA/CXC/MIT/F. Baganoff, R. Shcherbakov et al.

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The Center of our Galaxy by Josh Day

Have you ever wondered what is at the center of our galaxy? Evidence suggests there is a super massive black hole near the constellation Sagittarius, roughly 26,000 light years from our sun lies at the center of our galaxy.  Like our Milky Way, it is thought that most galaxies’ center around a supermassive black hole. The black hole at the center of the Milky Way is named Star Sagittarius A. It is one of at least 19 black holes in the Milky Way alone.

What is a black hole? It’s  “ a region of space time from which gravity prevents anything, including light from escaping”. A black hole is created when a star that is at least 30 times the size of our own sun uses up its nuclear fuel and its core collapses. What happens after is a shock wave that destroys the rest of the star. The core that is left behind is so heavy it creates a region of space-time cut off from the rest of the universe.

Studying black holes is hard as black holes swallow any nearby light making them almost invisible. So scientists have turned their attention to the stars that are affected by the gravitational pull of the black hole. Since 1992 researchers have been following a star, named S-2, orbiting Star Sagittarius A giving the researchers more information on the black hole. S-2 has passed within 16 light hours (roughly 3 times the distance from Pluto to our sun) from the black holes event horizon, or the point of no return. Anything that passes past the event horizon will be sucked towards the black hole by its gravitational pull, not even light can escape its gravitational pull once inside of the event horizon. Scientists now estimate the black hole having a mass of 4.5 million solar masses, or 4.5 million suns. With such a great mass the star S-2 is the fastest known orbiting body traveling at speeds near 11 million miles per hour. S-2 and 28 other stars’ orbits are being tracked giving scientists a better idea of exactly where the black hole is located.

All of this research points to a Supermassive black hole at the center of our galaxy. That’s right an unstoppable force whose gravity crushes stars, and nothing can escape from, not even light, sits at the center of our Milky Way. But nothing to worry about this black hole is 26,000 light years away.



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Broderick A, Loeb A. 2009 Nov 25. Portrait of a Black Hole [Internet]. Danvers (MA): Copyright Clearance Center, Inc.; [cited 2013 April 5] . Available from: http://www.scientificamerican.com/article.cfm?id=portrait-of-a-black-hole

Eckart  A, Schödel R, Straubmeier C. 2005. Black Hole at the Center of the Milky Way [Internet]. Imperial College Press; [cited 2013 April 5]