We now know that black holes occur frequently throughout the universe. One Sagittarius A* sits at the center of our galaxy, the Milky Way. In fact, according to NASA most galaxies of a similar size have monster black holes at their center. Sagittarius A* has approximately 4 million times more mass than the Sun.

Astronomers have observed three types of black holes in the universe. Stellar-mass black holes formed from the collapse of a massive star, intermediate mass black holes found in some star clusters, and supermassive black holes that lurk in the centers of galaxies.

If microscopic black holes born a fraction of a second after the Big Bang exist, then at least one may fly through the solar system per decade, generating tiny gravitational distortions that scientists can detect.

The Hubble Space Telescope has once again delivered extraordinary images from the distant corners of the universe. This time, its subject of observation was the galaxy IC 4709, located 240 million light-years away in the constellation Microscopium.