Q&A: Black Holes

Q:
What is the meaning of the "*" in Sagittarius A*?

A:
The name 'Sagittarius A*' refers to the believed location of the supermassive black hole in the center of our galaxy. About 50 years ago, astronomers identified an area within the constellation of Sagittarius that was the strongest region of radio emission -- thus making it the likely center of the Milky Way. Astronomers dubbed this region 'Sagittarius A' to identify this particular area within the large patch of sky that this constellation covers. As science and technology improved, astronomers were later able to pinpoint a more exact location of the suspected location of the supermassive black hole through a variety of techniques. This improved location of the black hole was then named Sagittarius A* to separate it from the larger region of Sagittarius A.