Google+ reshared post
One of the clearest indications of a supermassive black hole in our galaxy is the motion of stars in that region. In the image below, the motion of stars are tracked over about 15 years. By calculating the orbits of these stars we can determine the mass of the central black hole, which is about 4 million solar masses.
What makes this particularly cool is that this region is obscured by dust, so we use radio astronomy to peer behind the dust and detect the stars.
Importé de Google+