A ninth planet?

John Matese and Daniel Whitmire, from the University of Louisiana at Lafayette, are claiming that data from NASA’s Wide-field Infrared Survey Explorer already suggests that there is a large planet in the outer solar system. This hypothetical planet, which they have nicknamed Tyche, orbits the sun at 15,000 AU’s and weighs in at four times the mass of Jupiter. (Apparently Matese suggested this theory as early as 1999 based on perceived statistical fluke in the orbit of comets.)

When I read this I wondered at first whether it was even conceivable, and in particular would 15000 AU’s even still be considered in our solar system? I looked it up, and it is thought that the sun’s gravitational field dominates that of other stars out to about two light-years, or 125,000 AU’s. The Oort cloud, a hypothetical cloud of a trillion comets, which Freeman Dyson has speculated to be a possible long-term home for our distant descendants, is thought to be between 50,000 and 100,000 AU’s from the sun.

It seems that the Tyche hypothesis is not widely accepted in the astronomy community, and NASA has demurred, suggesting that we will know more in coming months or years. I, for one, welcome our new giant planet overlord.

Thanks to Dr. Heiser for the link.