Astronomers Claim Discovery of Earth-like Planet 225
Raver32 writes "A team of astronomers announced they have discovered the smallest and potentially most Earth-like extrasolar planet yet. Five times as massive as Earth, it orbits a relatively cool star at a distance that would provide earthly temperatures as well, signaling the possibility of liquid water. 'The separation between the planet and its star is just right for having liquid water at its surface,' says astronomer and team spokesperson Stephane Udry of the Observatory of Geneva in Versoix, Switzerland. 'That's why we are a bit excited.' But researchers do not yet know if the planet contains water, if it is truly rocky like Earth, which might make it hospitable to life as we know it, or whether it is blanketed by a thick atmosphere. 'What we have,' Udry says, 'is the minimum mass of the planet and its separation" from its star.'"
Re:5x mass = 5x gravity (Score:4, Insightful)
I think that in planetary terms we can safely assume 5x mass will create an environment of roughly 5g ... maybe give or take 20%. Enough to ensure that the simple act of getting out of bed would be a gruelling ordeal.
Another problem I noticed after actually reading TFA:
Gliese 581 c, orbits at one fourteenth the distance between Earth and the sun. But the red dwarf is 50 times cooler than the sun. The group estimates that the planet would experience temperatures in the zero-to-40-degree-Celsius (32-to-104-Fahrenheit) range.
It is my understanding that red dwarfs, while generating reduced heat and light output, produce solar flares that are almost as intense as those produced by a G class star. So if a planet exists in the habitable zone it is also exposed to periodic sterilizing blasts of charged particles.
Maybe if we're lucky the planet happens to have a really strong magnetic field ... then we just have the crushing g load to contend with.
Re:5x mass = 5x gravity (Score:5, Insightful)
The odds against it happening elsewhere are ... well ... astronomical.
The universe contains a very large number of elsewhere.
Re:5x mass = 5x gravity (Score:5, Insightful)
It's a poorly written and shite article, but the box off to the side says:
One of two newly discovered exoplanets is nearly the size of Earth...
So, assuming they're talking about the same one, it should be roughly 5 times our gravity.
Not so. If the planet has twice the diameter of earth, that falls well within the category of "nearly the size of Earth" for astronomers. Since gravity decreases proportionally to the square of the distance, gravity would be only 5/(2^2) times as strong as on Earth, an increase of a mere 20%.
If it has approximately the same density as earth, then since volume of a sphere increases proportionally to the cube of the radius/diameter, it would have 5^(1/3) times as large a diameter as earth, which is about 1.71 -- even closer to the size of our Earth. It would also wind up with gravity 1.71 times as strong, since 5/((5^(1/3))^2) == 5/(5^(2/3)) == 5^(1/3).
Re:That's it! (Score:3, Insightful)
You mean dead, desiccated prisoners. How long would it take Voyager to travel 20 ly? And we want to send people on that trip? Do we tell them we're going to use a worm hole/star gate/warp drive on the ship and that's why they're only getting a single soda and pack of peanuts for supplies?
Re:Interesting find. (Score:5, Insightful)
Re:5x mass = 5x gravity (Score:3, Insightful)
you're both missing the point, if the planet has water, then the only factor is compression ratio, aquatic life don't suffer from gravity like land bound creatures do, if they have neutral buoyancy the only effect of gravity they feel is the relative pressure of the water at the depth they live in.
considering there are whales that can go very deep in the ocean, to the very surface, the pressure regulation seems to be easily solved.
gravity only becomes an issue when life tries to evolve from aquatic life to land based life.
without oceans the planet won't develop enough diversity of life to populate the land. and it's far enough away that we can't tell if it has oceans.
Re:That's it! (Score:3, Insightful)
Actually, not the telephone sanitizers. We might want to keep those around.