Galactic picture day: See first photo of Milky Way black hole
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| Washington
The world鈥檚 first image of the chaotic supermassive black hole at the center of our Milky Way galaxy doesn鈥檛 portray a voracious cosmic destroyer but what astronomers Thursday called a 鈥済entle giant鈥 on a near-starvation diet.
Astronomers believe nearly all galaxies, including our own, have these giant black holes at their bustling and crowded center, where light and matter cannot escape, making it extremely hard to get images of them. Light gets bent and twisted around by gravity as it gets sucked into the abyss along with superheated gas and dust.
The colorized image unveiled Thursday is from an international consortium behind the Event Horizon Telescope, a collection of eight synchronized radio telescopes around the world. Getting a good image was a challenge; previous efforts found the black hole too jumpy.
鈥淚t burbled and gurgled as we looked at it,鈥 the University of Arizona鈥檚 Feryal 脰zel said.
She described it as a 鈥済entle giant鈥 while announcing the breakthrough along with other astronomers involved in the project. The picture also confirms Albert Einstein鈥檚 general theory of relativity: The black hole is precisely the size that Einstein鈥檚 equations dictate. It is about the size of the orbit of Mercury around our sun.
Black holes gobble up galactic material, but Professor 脰zel said this one is 鈥渆ating very little.鈥 It鈥檚 the equivalent to a person eating a single grain of rice over millions of years, another astronomer said.
鈥淧ictures of black holes are the hardest thing to think about,鈥 said astronomer Andrea Ghez of the University of California, Los Angeles. She wasn鈥檛 part of the telescope team but earned a Nobel Prize for the discovery of the Milky Way鈥檚 black hole in the 1990s.
She said the image of 鈥渕y baby鈥 is exactly how it should be 鈥 an eerie-looking orange-red ring with utter blackness in the middle.
Scientists had expected the Milky Way鈥檚 black hole to be more violent, especially since the only other image from another galaxy shows a far bigger and more active black hole.
鈥淚t is the cowardly lion of black holes,鈥 said project scientist Geoffrey C. Bower of Taiwan鈥檚 Academia Sinica Institute of Astronomy and Astrophysics.
Because the black hole 鈥渋s on a starvation diet鈥 so little material is falling into the center, and that allows astronomers to gaze deeper, Dr. Bower said.
The Milky Way black hole is called Sagittarius A* (with an asterisk denoting star). It鈥檚 near the border of Sagittarius and Scorpius constellations and is 4 million times more massive than our sun. Dr. Bower said it is probably more typical of what鈥檚 at the center of most galaxies, 鈥渏ust sitting there doing very little.鈥
It is incredibly hot, trillions of degrees, Professor 脰zel said.
The same telescope group released the first black hole image in 2019. The picture was from a galaxy 53 million light-years away that is 1,500 times bigger than the one in our galaxy. The Milky Way black hole is much closer, about 27,000 light-years away. A light year is 5.9 trillion miles.
To get the picture, the eight telescopes had to coordinate so closely 鈥渋n a process similar to everyone shaking hands with everyone else in the room,鈥 said astronomer Vincent Fish of the Massachusetts Institute of Technology.
Astronomers worked with data collected in 2017 to get the new images. The next step is a movie of one of those two black holes, maybe both, Dr. Fish said.
The project cost nearly $60 million with $28 million coming from the U.S. National Science Foundation.
Even though it is quieter than expected, the center of the Milky Way is an important place to study, Professor Ghez said.
It鈥檚 鈥渓ike an urban downtown, everything is more extreme. It鈥檚 crowded. Things move fast,鈥 Professor Ghez said in an interview. 鈥淲e live out in the suburbs [in a spiral arm of the galaxy]. Things are calm out here.鈥
This story was reported by The Associated Press. The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute鈥檚 Department of Science Education. The AP is solely responsible for all content.