On which planet or moon, as far as we know, life is most possible (other than Earth, of course)? And where is that planet?

Answer

Gliese 581c and d are two planets around the star Gliese 581, one of which is likely to lie within their star’s ‘habitable zone’. The star is about 20 light-years away from us, and is located in the constellation of Libra.

What is the habitable zone? The zone around the star where liquid water can occur, on solid planets. Too close to the star the water is vapor, too far the water is ice. You need a solid planet because oceans can only exist on it.

To really say which of the 500 already known planets around other stars has the greatest chance of life, we still know very little:
– one thing is to say that there is liquid water and that water may be necessary for life, but that does not mean that liquid water always leads to (developed) life;
– the habitable zone of a star depends not only on the star, but also on the planets themselves: if they have a thick atmosphere, it is warmer there, and we know nothing about the atmospheres of the known planets in habitable zones;
– it’s hard to say how a planet’s mass plays a role. The greater the mass, the more likely the atmosphere, and too much atmosphere is no good; well, all known planets are a lot heavier than Earth.

If we had the means and the technology (and the volunteers…) now to look at a planet deep in the universe, I would advise waiting a few more decades: then we will know much better where to go. go with a chance of success.