Nemesis, named after a Greek goddess of divine retribution, is also known as the "Death Star" due to the belief that the star is the main cause of death among a variety of different species on Earth. One common question one would ask is: There's an evil twin out there of our sun? Well, where is it? How come we can't see it? Nemesis is not believed to be a very bright or large star. In fact, Nemesis is believed to be much smaller and dimmer than our sun. Some scientists believe the star could be a brown or black dwarf (a planet-like body who size is not suffient enough to "burn hydrogen" like a regular star to glow, making the star's appearence that of a dark sphere of gas and very difficult to find, and, in some cases, almost invisible. For all we know, Nemesis could have already been discovered and is inconspicuously listed under one of the cataloges for dim stars. Its great parallax, the motion of a star against the background of other distant stars, may have been otherlooked. However, even if scientists discovered Nemesis, few would think the star had any involvement in the Earth's periodic mass extinctions.