It has been suspected for some time that there is a supermassive black hole located at the center of our galaxy, named Sagittarius A*. Now scientists have uncovered more evidence about the black hole which they shared in an announcement on October 31.
Cosmologists have used the Very Large Telescope (VLT) to observe flares of infrared radiation from the disk of debris surrounding Sagittarius A* (pronounced A-Star), which is strong evidence that it is a supermassive black hole. A consortium of scientists at the European Southern Observatory (ESO) used the GRAVITY telescope interferometer to observe three bright flares orbiting around Sagittarius A* at a tremendous speed of 30 percent of the speed of light. The flares are believed to be caused by the heated gases that orbit Sagittarius A* which interact with the magnetic fields surrounding them, and are in line with what scientists predicted would be seen around a black hole.
ESO released a video which shows a beautiful visualization of zooming into the black hole and seeing the swirling pattern of the flares that surround it:
This is the first time that material has been observed so close to the event horizon of a black hole. The event horizon is a region around a black hole from which nothing can escape — not matter or even light. Because black holes are so dense, they have very strong gravity which pulls anything within the event horizon back towards the black hole and prevents it from escaping. Just outside of the event horizon is a point called the innermost stable orbit, which is the closest that matter can come to the black hole without being dragged into it, and this is where the flares observed by the ESO originated. The innermost stable orbit is part of the accretion disk, which is the disk of gasses and other matter that forms around a black hole but which is far enough away not to be pulled inside the event horizon. The forces of friction and gravity combine to compress these gases and raise their temperature, which is how the flares form.
As a supermassive black hole, Sagittarius A* is even stronger than most black holes due to its enormous size. We now have confirmation that this cosmological giant is the center around which the entire Milky Way galaxy rotates.
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