Many Earth-like planets may exist in Milky Way

“As many as 60% of Sun-like stars in the Milky Way may form rocky planets similar to Earth, according to recent findings from NASA’s Spitzer Space Telescope.” Linky: New Scientist article.

It’s not like I didn’t already kinda think there were lots and lots of earth-like planets, but it’s nice to have scientific-ey confirmation. So where’s all the aliens?

The interesting thing though, was at the end of the article:

That’s cool! Earth or larger objects in our very own solar system and we haven’t found them yet?

Does anyone else think that’s cool?

When my local paper reported on this, they said that there are “billions more planets than previously though in our solar system and galaxy.”

Oh, well obviously they’ve been studying Joss Whedon’s Guide to Firefly Solar Systems.

Yes, they would be really cool. Like minus 273 degrees.

Oh for heaven’s sake. This is why we need more Minnesotan astronauts. They don’t bitch about the cold.

It would be highly surprising to find objects approximately the mass and density of the Earth within the Kuiper belt; we might not be able to see a low albedo object, but the gravitational perturbations should indicate its existence. Trans-Neptunian Objects (TNO) further out in the scattered disk are possible but tend to be contraindicated by accepted theories of solar system formation; an object as massive as the Earth would be unlikely to be thrown into a long orbit by coupling between two planets (even Jupiter and Saturn), and its periodic return should wreck havoc with the existing stability of smaller worlds or Jovian moon systems. It might be that such an object was drawn out by some type of long period “Nemesis” object, but no such partner has been found to date, and if it did exist it may be thousands of AU outside of the main system; barely a part of our Solar System and easily perturbed by outside forces. In short, if there are any Earth-like worlds out there, they’re probably too far to be seen or of any use.

Regarding Earth-like worlds around other systems, given the vast number of stars it seems almost certain that they exist, and even quite possible that planets of the approximate size and composition are common. However, a world with conditions that are livable for us is much less likely; we have only a rudimentary understanding of the development of Earth, but it is clear that just being within a habitable zone isn’t of itself sufficient.


Well, that’s what I was thinking. Surely things with big, big gravity should be tugging enough we’d know about them.

This Stern guy is a planetary scientist at NASA. Surely we don’t employ dorks at NASA. Geeks probably, but not dorks.

What if an earth-sized planet were on a Sedna-like orbit? Perhaps also in some orbital resonance (like Pluto) with Neptune.

We’d also have to rehash the debate about what’s planet and a not-planet.