COSI team member Michael Humphrey asked me via email: is there any truth to the so-called "Planet X"?
Answer for the impatient: No.
Answer for those who don't even know what I'm talking about:
Every once in awhile rumors start swirling, bouncing from ear to ear and facebook feed to facebook feed, about a giant planet in the outer reaches of the solar system, careening sunward with one goal on its gaseous mind: death to Earth.
I mean, of course it's not true, because, you know, astronomers might've told you. But what's more interesting than a nonsensical rumor is its origins.
It's true that we don't know much about the outer solar system. It's large and it's dark, and like that one corner of your basement you never get around to sorting through, we're pretty sure it's just full of junk. We're constantly learning new things - for example, there are indeed some slight hints of a brand new giant planet waaay out there, but if it is out there it's staying out there.
There have also been some studies that tried to find a regular pattern in the extinction record on Earth, and posited that a giant outer planet would disturb a new batch of comets every few million years. Turns out there aren't regular patterns in the extinction record, but hey we tried.
The point is that while there are still spacey mysteries in our own back 40, it doesn't meant they have to be bad things.