Earth-Like Planets In Our Neighborhood

goran72 sends in a story out of the Chicago AAAS meeting contending that Earth-like planets with life-sustaining conditions may be spinning around stars in our galactic neighborhood — we just haven't found them yet. "'So I think there is a very good chance that we will find some Earth-like planets within 10, 20 or 30 light years of the Sun,' astrophysicist [Alan Boss]... told his AAAS colleagues meeting here since Thursday. ... The images from those new planets, he added, should identify 'light from their atmosphere and tell us if they have perhaps methane and oxygen. That will be pretty strong proof they are not only habitable but actually are inhabited. I am not talking about a planet with intelligence on it. I simply say if you have a habitable world. ... Sitting there, with the right temperature with water for a billion years, something is going to come out of it. At least we will have microbes,' said Boss."

Comments

Re:impossible dream?

[shawb]

While it initially appears that you would be traveling faster than the speed of light, you indeed are not... when you reach relativistic speeds space itself compresses, so from your perspective the distance traveled between two points is less than the distance as measured from a resting observer. End result your measured velocity is less than C. To the resting observer, you travel the larger distance, but time is dilated such that your velocity is lower than C. Since the apparent distance between the origin and the destination is decreased, the amount of time it takes light to make the same journey would be less than the amount of time it takes you. In fact, from your perspective light is still traveling... at the speed of light.

Now, to take the concept to the ultimate (but unreachable) conclusion: to reach such a velocity that an outside observer would record you as moving equal to the speed of light: To the traveler it would seem as if there was actually no distance traveled, and the journey took no time at all. What the traveler would observe is space and time folded between the origin and the destination... for a 10 light year journey, you would instantly travel to the destination, but 10 years later. The return trip would also be instantaneous, but 20 years would have elapsed at home since you have left. Thus, the speed of light is not violated. However, to cut your travel time to zero in a Newtonian framework, you would need to reach infinite speed in zero time, which would require infinite acceleration, which would in turn require infinite energy. That is impossible, so an object with a resting mass cannot travel at the speed of light (or beyond.) But you still have to take into account the fact that at relativistic speeds, space constricts while time dilates, allowing for what on the surface appears to be traveling faster than the speed of light, but actually is not.

Re:Polluted by life?

[Ihlosi]

There have been spores tested, and the verdict is that they can survive at less than 10cm to an atomic explosion.

Citation needed.

A couple thousand degrees temperature will break up pretty much any chemical bond.

One atomic bomb can kill, at best, about 50000 people, in a dense city block less than 1 square kilometer.

Eh, what? Both of the bombs used in anger so far killed more than that (both directly by the blast and delayed deaths by radiation). And, mind you, those were small 10-15 kT devices. In todays strategic arsenals, you'll warheads ranging from a couple hundred kilotons to 1.2 megatons. And then of course, there's this little baby:

http://en.wikipedia.org/wiki/Tsar_bomba

Re:Question

[EllisDees]

This will give you some idea how large a nuclear blast is:

Ground Zero simulator