Phil Plait: There’s No Proof of A Giant Ninth Planet.

If you’re an astronomy geek like myself, Phil Plait is the man. His blog Bad Astronomy features daily space porn, and more than that, it features dissections and explanations of said space porn. When I mentioned the possible ninth planet Tyche a couple of days ago, I used the disclaimer, “I’m telling you to take everything I’m about to blather about as  more than likely science fiction.”

According to Phil Plait, I’m probably right.

Bad Astronomy:

Here’s the deal. Two astronomers, John Matese and Dan Whitmire, have theorized about the possibility of a previously-undiscovered planet way beyond Pluto for some time. This is not a crazy idea; we see planets orbiting other stars way out, and  there’s other evidence big planets can be pretty far out from the Sun (mind you, evidence does not mean proof). As it happens, there are lots of chunks of ice orbiting the Sun pretty far out as well. Some of these have orbits which bring them into the inner solar system, and we seem them as long-period comets.

What Matese and Whitmire did was wonder how a big planet would affect the orbits of these comets. If you measured enough of them, would you see the effects of the gravity of this planet? They claim you can, and even gave the planet a tentative name: Tyche.

I’ve been in the Astronomy Geek Rodeo to understand things like this. Evidence never means proof. As I often say, it doesn’t stop me from getting excited.I have a monstrous imagination. Just the concept of a lurking ninth planet? Enough to get me stoked. Plait continues:

I read their papers, and thought the data were interesting but unconvincing. The sample size was too small. A bigger study was done, but again the effects weren’t quite enough to rise to the level of breakthrough. I’m not saying the astronomers are wrong – the data were certainly provocative, and potentially correct! Just not firm enough.


This planet may not exist at all. It  might, and I’d love for that to be true. But at the moment we just have interesting but inconclusive evidence supporting the idea of a large planet in the deep dark recesses of the solar system. That’s a long way from proof.

Why do I post things like the possible ninth planet? It’s fun to imagine stuff like that. Plus, it isn’t that it doesn’t isn’t there (though I would be that’s the case), it’s just that the whole OMFG IT’S THERE WE JUST NEED TO SEE IT contingent is getting a bit ahead of itself.

Read more: here. Speculating is good, but healthy skepticism and analysis of the data is even better.