Wie viele verschiedene Varianten unseres Heimatplaneten gibt es da draußen.

Wenn wir einen finden, sieht er dann so aus wie unsere Erde?
Ein Team ist der Sache jetzt nachgegangen :

'Earth-like' Planets May Be Nothing Like Earth

...The authors conclude: "There could be billions of Earth-like planets in the universe but a great majority of them may have a totally different internal and atmospheric structure. Building planets in chemically non-solar environments (which are very common in the universe) may lead to the formation of strange worlds, very different from the Earth!"...

http://news.discovery.com/space/susp...th-120229.html