Original: In 1998 , astronomers found compelling evidence that a supermassive black hole of more than 2 million solar masses is located near the Sagittarius A \* region in the center of the Milky Way galaxy , and more recent results using additional data find evidence that the supermassive black hole is more than 4 million solar masses .
Simplified: After observing the motion of nearby stars for 16 years , in 2008 astronomers found compelling evidence that a supermassive black hole of more than 4 million solar masses is located near the Sagittarius A \* region in the center of the Milky Way galaxy .