Our galaxy hides a giant black hole
At the center of the Milky Way sits Sagittarius A*, an invisible object with about 4.3 million solar masses. Astronomers figured this out by watching stars whip around something they could not see.Black Holes: How We Found the One in the Milky Way
The stars gave it away
Since 1995, astronomers have tracked the motions of 90 stars near the center of our galaxy. One star, S2, completed a full orbit around the hidden object, helping scientists pin down its mass and tiny size.Black Holes: How We Found the One in the Milky Way
