Does the Nemesis Companion Exsist?

Nemesis - A small dark companion star to Sol, orbiting the outer reaches of the solar system, sending comets hurtling from the dark reaches of the Ort cloud towards the inner planets of the Solar System. Some of which strike Earth, said to be the cause of mass extintions throughout history. Unfortunatly for Nemesis, it's exsistance falls apart because it could not have a stable enough orbit to account for the regularity of the extintion events.

However, since a disproportionatly large amount of comets originate from the Oort Cloud, University of Louisiana astrophysicists suspect that a large object may indeed be lurking deep in the outer reaches of the Solar System.

From the IO9 article:

• A planet anywhere from one to four times the mass of Jupiter could be responsible for the gravitational influence that would create this imbalance. .... the probability that this effect is purely a statistical fluke is extremely small, which suggests there's something strange going on out there in the outer Oort.

Even though the object would be Jupiter class in size and mass, its' shere distance from the sun (in an order of 30,000 times farther away than Earth) would make it extremely difficult to discover.

Wiki reference IO9 article