Nemesis (hypothetical star)

Nemesis is a hypothetical star that some people think might exist. It's a star that is supposed to be very far away from Earth, and it moves in a regular pattern around the Sun. People think that it's possible that it moves in a pattern that causes it to come close to the Earth every few thousand years. Some people say that when Nemesis comes close to Earth, it causes bad things to happen, like earthquakes, floods, and other disasters. It's just a theory -- there's no one who knows for sure if Nemesis really exists.