The Galaxy May Have Billions of Habitable Planets

The Bad Astronomer writes "A recent astronomical report (abstract in Science) came out stating that as many as 1 in 4 sun-like stars have roughly earth-mass planets. But are they habitable? A simple bit of math based on some decent assumptions shows that there may be billions of potentially habitable worlds in the galaxy. '... astronomers studied 166 stars within 80 light years of Earth, and did a survey of the planets they found orbiting them. What they found is that about 1.5% of the stars have Jupiter-mass planets, 6% have Neptune-mass ones, and about 12% have planets from 3 – 10 times the Earth’s mass. This sample isn’t complete, and they cannot detect planets smaller than 3 times the Earth’s mass. But using some statistics, they can estimate from the trend that as many as 25% of sun-like stars have earth-mass planets orbiting them!' Getting to them, of course, is another problem altogether..."

Comments

Charles Stross has a great article on this.

[Peter Trepan]

The High Frontier, Redux - Covers the true scale of the distance between planets, and the energy requirements of going between them. He estimates that sending an Apollo-sized capsule to the nearest star would take as much energy as is produced on Earth in a year.

Re:Fermi's paradox.

[MyLongNickName]

I wonder what happens if we continue to expand our knowledge about exoplanets at the current rate but we don't discover life on another planet by the year 2100. Fermi's Paradox bugs the hell out of me. I can't see how we are unique... but I also can't see why the evidence of other civilizations wouldn't be obvious.

Generational Ships

[Sloppy]

With cryo-stasis ships, at least there's a reason to eventually settle somewhere. You want to wake up (or stop taking watches) and eventually start your new life. You can bear the hardships of the journey, because you have a personal goal that you intend to some day fulfill.

The thing about generational ships, is that if they're really self-sufficient and comfortable enough that the early generations don't go mad, then what's the point of landing anywhere? You can say that humans need to expand, but the people onboard won't be able to meet that need, and they're just going to have to cope with such a limited existence. But if they succeed, then that culture will be passed down, so you'll have a whole population that is happy staying in their little box. How can you plan so far into the future and keep the plan intact?

There's a Star Trek episode ("The World is Hollow And I Have Touched the Sky") where the people don't even know they're on such a ship, and the more I think of it, the more realistic and believable that seems. People wouldn't ever be able to stick to such a long-term mission in which they don't personally have any stake, so they might as well not be depended upon to achieve it, or even know it's happening. One single centralized authority with infinite patience (a computer) and a secret and tyrannical agenda, is about the only thing that could keep it going.