The Theory of Nemesis and Reoccurring Mass Extinctions.
For several decades, the topic of periodical mass extinctions has been one of much debate and speculation by the scientific community as well as the media and public. Throughout the past few decades many theories have been researched, but a constant struggle for acceptance and recognition between each theory prevents one from standing out among the others. However, in the 1980's one particular theory began to make headlines in literature throughout the science world as well as in more widely recognized media such as Time and the New York Times. The theory states that the Sun, which was long thought to be a single star, may actually have a companion star. As this proposed star orbits the sun, it is possible that certain comets may have been thrown out of their orbit by its gravitational field. (Goldsmith 1985) These comets were then directed at Earth, thus causing catastrophic events upon impact such as the extinction of the dinosaurs sixty-five million years ago. In 1984 this theory came to be known as the Nemesis Theory. Research has given much support to this theory, but there as also been substantial opposition with many questions left unanswered. Because this theory deals with topics so intriguing to human beings, it can be assumed that our interest in it will keep research alive until a decisive answer is reached.
Nemesis is one of several names given to our Sun's companion star. (Raup 1986) It is thought to be a small star that is around 2 light years from us and moving away. However, within a few million years, Nemesis will turn back in its orbit and begin to come closer to Earth. This trip back will take many more million years before it completes an orbit. As its orbit nears the Sun it will pass through the Oort Cloud, a patch of billions of comets which orbit the Sun beyond Neptune. The gravitational force of Nemesis will then be able to send some of these comets in random directions.