Tour: Telescopes Show the Milky Way's Black Hole is Ready for a Kick

The supermassive black hole in the center of the Milky Way is spinning so quickly that it is warping the spacetime surrounding it into a shape that can look like an American football. This result was made using data from NASA’s Chandra X-ray Observatory, an X-ray telescope in space, and the NSF’s Very Large Array, an array of radio telescopes in New Mexico.

Astronomers call the giant black hole Sagittarius A*, or Sgr A* for short. It is located about 26,000 light-years away from Earth in the center of our Galaxy.

Black holes have two fundamental properties. The first is their mass, or how much they weigh. The second is their spin, or how quickly they rotate. Determining either of these two values tells scientists a great deal about any black hole and how it behaves.

While astronomers are confident they know how much mass Sgr A* has (about four million times that of the Sun), they have had a harder time trying to nail down just how fast Sgr A* is spinning. This new study involves method that uses X-ray and radio data to determine how quickly Sgr A* is spinning based on how material is flowing towards and away from the black hole.

The results show that Sgr A* is spinning very fast. In fact, scientists think that it is rotating so quickly that it is warping spacetime around it into a shape that looks like an American football. Spacetime is the term for the combined concept of time and the three dimensions of space. Scientists have known for a long time that black holes can do this, but this is strong evidence that our own Milky Way’s black hole is having this effect.

How quickly a black hole is spinning also has other important implications. For example, a black hole’s spin can act as an important source of energy. Spinning supermassive black holes can produce narrow outflows in the form of jets when their spin energy is extracted. Sgr A* is currently rather quiet, but this new finding means that it could become more active in the future. Scientists will continue to use Chandra to study Sgr A* to better understand this black hole and its role in our Galaxy.