Planet X is back … the Kuiper Cliff explained?

How did I miss this? Not that anyone’s actually found the mystery object that might just be causing that big old drop-off at the edge of the solar system we call the Kuiper Cliff, but …

The Planet X hypothesis has come to the fore once again, as researchers in Japan propose in a new paper that an object up to two-thirds the size of Earth might lie undiscovered out beyond Neptune somewhere. This would have cleared the debris from the outer part of the solar system thereby creating the relatively empty zone whose edge is marked by the Kuiper Cliff, hence the name of this blog. Bad Astronomy and The Daily Galaxy have good breakdowns of the research, which was admittedly based on computer simulations, and suggest that the Planet X theory may still have some legs.

I’m all up for a new planet, particularly since Pluto was demoted, but I’m also happy for the mystery to carry on. After all, as Ralph Waldo Emerson said, “Men love to wonder, and that is the seed of science.” Although, in the context of the ongoing Planet X story, perhaps we should also remember Mark Twain: “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”