How common are Earthlike worlds?

[james_davis_nicoll]

Perhaps not very common at all, although even low percentages work out to large absolute numbers.

On the other hand,

By combining all the data, including observations of stars that did not have planets, and looking at the fraction of existing planets that could be discovered, the team has been able to work out how common different sorts of planets are around red dwarfs. They find that the frequency of occurrence of super-Earths in the habitable zone is 41% with a range from 28% to 95%.

Comments

[anzhalyumitethe.livejournal.com]

I have to wonder if the reason for the Fermi Paradox is simply that there are a million smaller reasons acting in concert and no one (as yet) has overcome them.

Frex, if superearths are more common than our size earths, getting off planet may be significantly harder.

And if life actually arises more in Europa-like satellites, then it may be that is another contributor.

Plus that interstellar travel is very very expensive.

etc, etc.

There is no one unified reason and life is really out there, even intelligent life.

Then again, someone had to be first...why not us?

[roseembolism.livejournal.com]

Not at all surprising. I've suspected for a while that the sheer diversity in planetary systems means that earthlike planets in the habitable zone will be rare.

[andrewwheeler.livejournal.com]

Cutting through the thicket of words in your link, there's still two stark points:

* It's vastly easier to detect Super-Jovians than any other type of planet.
* It's vastly easier to detect smaller, rocky planets when they are exceptionally close to the primary.

The author does note that, as more data emerges, the range of planets than can be detected is converging on the Earthlike world -- small, rocky, but at a medium distance from the primary -- but there's still a lot of handwaving going on about how much of that range is detectible at this point.

To my mind, we're still in the situation of the drunk who lost his car keys at night: we're looking next to the streetlight, because that's where we can see best. The data simply aren't there yet to determine how common Earthlike worlds are, and won't be there until and unless our detection methods reach the point when they can consistently find Earthlike worlds.