M82 Two groups of astronomers have discovered a new kind of black hole. The galaxy named M82 may have one of these new black holes in its center. Until now, it was believed that black holes came in two sizes, stellar which are small, and super-massive which are really large.
Astronomers think that stellar black holes are what are left from a burned out star.
These remains are several times heavier than our sun, but are squished down to only a few miles wide. Astronomers think that combining millions or billions of stars or giant gas clouds squished together creates super-massive black holes. The super-massive black holes are wider than millions of stars. The new kind of black holes are different because they are medium sized and are only 100 to 10,000 times heavier than our sun but are smaller than our moon. They can be found in spiral -shaped galaxies.