In the
Breaking Science News forum,
bystander just a summary of a Yale University study of what makes planets habitable:
Jim Shelton wrote:
A new study, appearing in the journal Science Advances on Aug. 19, suggests that simply being in the habitable zone isn’t sufficient to support life. A planet also must start with an internal temperature that is just right. ...
“What we take for granted on this planet, such as oceans and continents, would not exist if the internal temperature of Earth had not been in a certain range, and this means that the beginning of Earth’s history cannot be too hot or too cold.”
When you think of it, it seems self-evident that being inside the habitable zone isn't enough for a planet (or a large moon) to be habitable. The Earth's Moon is most certainly in the habitable zone of the solar system, but it is not a habitable world by any stretch of the word. On the other hand, distant and terribly cold Titan with its ethane and methane lakes could just possibly be the perfect sort of world for beings adapted to swimming around in liquid hydrocarbons.
Being in the habitable zone of a star is no guarantee that the planet or moon will be habitable, but being outside the habitable zone does not necessarily mean that the planet or moon is
not habitable.
So what do you think yourself?
1) Could the Earth's Moon ever have been habitable? Can pure chance ever make it habitable in the future? Can humanity ever make it habitable? If so, how?
2) Is
Mars habitable? (I suppose a lot of you, including Chris, will say yes.) If we find any sort of present life on Mars, and we may well do that, then the problem is solved - Mars is habitable. But suppose we will be able to apply some sort of test on Mars, which will clearly tell us if there is any biological life on Mars today or not. Suppose we find there is no life on Mars at present. If there is no life on Mars today, but Mars still has all the other characteristics that we know it to possess, is Mars then still habitable? Could it become more habitable in the future than it is now?
3) Is it possible or even likely that Jupiter's moon
Europa is habitable? What about
Ganymede and
Callisto?
4) How likely is it that
Titan is habitable? By what definition would it be habitable?
5) Could
Enceladus be habitable?
6) Could Neptune's moon
Triton be habitable?
7) Could
Pluto be habitable? Just think of those terrifically large slabs of ice on Pluto. What's below them? An ocean? With tiny little Plutonian life forms in it?
I'd love to hear it from you here! What do you think about this?
Ann
