Expert: Jayendra Upadhye - 1/10/2009

Question
With what we know about the universe today: can a moon be habitable to humans (having its own ecosystem - not requiring habitats and spacesuits), or would the temperature range as it orbits its planet make it too inhospitable.  If it orbits like the moons of Uranus (vertically to most of the rest of our system), then it wouldn't have a day/night cycle, would it?

Answer
Hi Meredith,
Nothing is ever impossible in this universe!
There are countless galaxies in it, and 100 billion stars per galaxy!
What then would be impossible?
Imagine a sol like sun.
then Imagine a very large planet, about 4 times as large as the earth. (say).
Further imagine, a carbon copy planet exactly like the earth orbiting this large planet at a safe distance!
(too close would phase lock it like our moon).
If this system was 93 million miles from that sol, it would be a moon you are looking for!
except the tides would be something worth seeing, and the focus of mythologies on it.

[Provided chance had it that blue green algae had in the first two billion years reduced the primitive atmosphere into an oxygen rich one, like the earth's].
regards
Jayen