Star Tossed Out Of The Milky Way Is Traveling At 3.7M Mph

Scientists have discovered a star that was tossed out of our Milky Way galaxy by the supermassive black hole at the center of the galaxy. The star whipped around the black hole long enough to get up to an incredible rate of speed. According to the scientists, the star, dubbed S5-HVS1, was spotted in the constellation Grus using the 3.9-meter Anglo-Australian Telescope near Coonabarabran, Australia.

Further observation by the ESA Gaia satellite showed that the star is moving ten times faster than most stars in the galaxy and will exit the Milky Way. The star is traveling at about 3.7 million miles per hour, according to the scientists.

Scientist Douglas Boubert says that the velocity of the star is so high that it will "inevitably" leave the galaxy and never return. The first star of this type was discovered only about two decades ago, and only a few examples are known so far. The stars are known as "hyper-velocity stars," and the only way they can escape the galaxy is to be accelerated to extremely high velocities by incredibly massive objects, such as supermassive black holes.

A hypothesis first put forward about 30 years ago suggests that a supermassive black hole would be capable of ejecting a star from the galaxy if a binary star came too close. In that instance, the black hole would eat one star and expel the other at high velocity; the process is known as the Hills Mechanism.

This new star discovery is the first time that there has been a clear association between a very fast star and the Galactic Center. Scientists believe that the star was ejected at a speed of thousands of kilometers per second about five million years ago. The ejection would have happened when human ancestors were first starting to walk upright.