Expert: Tom Whiting - 12/7/2011

Question
Hi,

A new Earth-like planet has been discovered, c.600 light years away. Based on the information in these 2 articles

http://www.telegraph.co.uk/science/space/8939138/Kepler-22b-the-new-Earth-could-

http://www.telegraph.co.uk/science/space/8937466/Nasa-discovers-new-Earth-Kepler


, what would you say the average global temperature of that planet is likely to be? Also, if you could give me any other estimates of habitability(eg:- the planet's gravity, whether humans could survive the (greater?)air-pressure at sea-level given the planet's greater size than Earth etc. etc.), based on the above information(even just vague, calculated  guesses if the above data is incomplete), I would be most grateful.

Thanks,
Geoff.

Answer
Hi Geoff,
Yes, I've seen basically the same information you have, but off the Kepler spacecraft website.
Other websites tend to "sensationalize" astronomical discoveries.  So I wouldn't read too much into this new discovery of Kepler.  By "Earth-like" they simply mean size and temperature, although the size I believe is 2.4 Earths, that's still pretty far from the Earth at 8000 miles in diameter.  I'm sure newer discoveries in the future will find still smaller planets.
And at 500 to 600 light years (I've seen both numbers mentioned)... it will be quite a while for any of our "radio transmissions" to get there, and double the return trip, if any.
(You gonna be around 1200 years from now to "receive" an answer? Which could be no answer at all.)

As far as life (That's a biology question isn't it?... not astronomy!).. but in any case, nothing more can be inferred from the discovery.  It could end up an all water planet, or the reverse... all rocks and zero liquid water like Mars. Could have a 95% carbon dioxide atmosphere, or 50% nitrogen and 50% Argon (we have 0.9% Argon here on Earth)... or no atmosphere at all!... no one knows as yet.  It could even be all cyanide compounds, totally poisonous to organic life forms... who knows?
We have no idea in fact, if it even has an atmosphere, yet you want me to "guess" at an atmospheric pressure?  That's ludicrous. It could range from zero to 100 atmospheric pressure.
(Venus is over 90 ATM's pressure).
Ahhh... astrobiology; the only college course without a subject! (as yet).  I wouldn't gamble and major in it... it could be centuries before we really know about and discover extra-terrestial life forms.  Plus... how does one earn a living in... astrobiology?
Clear Skies,
Tom Whiting
Erie, PA USA