Frank Merton, on 11 February 2013 - 08:24 AM, said:
I have a couple of problems with the red dwarf earth-like planet idea. To be in the comfort zone of such a star, you have to be close to it -- so close that in less than a billion years or so there will be a tidal lock, so that the planet always keeps the same face pointed at the sun.
Also, I understand that red dwarfs are far more prone to violent flaring and that such flares are much worse than on the sun. If my understanding here is right, doesn't that kinda make all this talk about so many earth-like planets being so close to us a bit (actually way) premature?
Not all red dwarf stars are prone to flaring. Even in those that do, their severity seems to be linked to their size. Those at the high end of their mass scale are less a problem in this regard. It has also been discussed that a dense atmosphere, and strong magnetic field might protect some such planets from too extreme effects of flares.
The main problem with tidally locked planets, seems to be the accumulation of heat on one side, and the freezing of the opposite. It appears possible that powerful convective cells of winds, or the heat distributing effects of oceans, or both, might make substantial portions of such planets livable. They could transport heat from the hot side to the cold side of these planets, moderating the temperature extremes to a substantial degree.
There is also the possibility of terrestrial-sized moons of a Jovian planets near a red dwarf. Some of these moons would also be in the star's habitable zone. Their 'day' would be the period of the moon's orbit about the planet. This could be a fairly rapid cycle-- on the order of several Earth days.
By the way, Proxima Centauri is about 280 million years older than our Sun. Supposing that the flares' effects on a planet of this star are not too severe, life could have had a 280 million year head start on us. I wonder how far we will have evolved in another 280 million years.
Edited by bison, 11 February 2013 - 05:04 PM.