Is It Planet X ... Or A Black Hole?

Okay, so we're dealing with a theory stacked on top of another theory here today. Astronomers have been looking for an object far out in the solar system because, according to what they've observed of current Kuiper Belt objects, something is disrupting their orbits. That something could possibly be a ninth planet, similar to Uranus or Neptune. It might not even be there, the data is sparse.

But let's say there is something out there causing gravitational mischief. The only requirement for this object is that it weighs something like 10 Earth masses. It doesn't HAVE to be a planet.

So a pair of physicists have suggested that a tiny black hole, similar in physical size to a grapefruit, is causing those trans-Neptunian objects to go off course. Their evidence? A series of brief microlensing events observed by the Optical Gravitational Lensing Experiment. Planets don't cause microlensing events like the ones the experiment observed, but a small black hole would. And the mass causing the events was consistent with the mass of the theoretical ninth planet.

The physicists noted that their theory is a wild one, and that it probably isn't a black hole. Like I said, we don't even know if there is something in the outer solar system causing gravity problems. But it would definitely be cool if our solar system had picked up a little black hole over the years. Rest assured, it would be no threat. You'd have to be really close to get sucked in by a black hole that weighed only a few times more than the Earth. Just remember, if the sun was replaced by a black hole of equal mass, Earth's orbit wouldn't change. We'd freeze, but we wouldn't get sucked in. That's not how gravity works.