I fully understand all the likely difficulties with life on tidally locked planets. But my point is that there may also be a few small benefits, with regards to potential life – particularly that even planets outside of the traditional “habitable zone” would likely still have that dusk/dawn edge sliver in which temperatures would be somewhere in between very hot and very cold. Thus “habitable zone” may not be a terribly useful concept for tidally locked exoplanets – for such planets, every one might have a very, very small habitable zone within that sliver where the night side meets the day side.
Despite the low light output, this star has a usable lifespan of trillions of years, as opposed to the mere billions that the Sun will last.
Wiki says that the age of the system is at least 500M years, so it should be past the Late Heavy Bombardment stage, and hopefully young enough for the planets to still have magnetic fields and atmospheres.
Being only 500M years old doesn’t bode well for there being life (yet), if our own planet is any indication. It took Earth about 1.2BY before the simplest life forms first appeared.
Then almost another 3 billion years after that before we got things like fish, plants and dinosaurs.
The earliest (not uncontroversial) signs of life on Earth are 4.1 billion years ago, or less than 500 million years after the Earth’s formation. (Peedy eff.)
The moon is in a moderately eccentric orbit (distance varies from about 220-240 thousand miles). So does the moon actually face the other focus?
Even so, anything resembling a pre-Cambrian-like explosion of life probably wouldn’t be enough for us to detect from 40 LY away.
That is, it took almost 3.5 billion years to go from microscopic life to complex organisms. I’m not holding my breath that we’ll find any signs of life, no matter how tenuous, after only 500 million years of possible evolution.
See Libration - Wikipedia for more on Moon eccentricity.
It doesn’t directly answer your question, but it’s another piece in the puzzle. The Moon has a constant rate of rotation vs. the fixed stars, but its angular velocity as perceived from the Earth changes as it goes around its orbit. With the result that the constant rotation alternately leads and lags the non-constant revolution.
Would it?
Seems to me you’d get some pretty spectacular winds as hot winds raced around to the cold side and the cold air raced towards the hot side.
Seems to me this mixing would keep things from doing as you suggest.
Note that the empty-focus thing only works to first order, so it won’t be much good for cometary-style orbits. And of course it’s meaningless for a perfectly circular orbit. But for moderately-eccentric orbits like, say, Mercury or Mars (if they were locked), it’s pretty good.
Haven’t noticed this quote before:
TRAPPIST-1 would be able to warm the air on the surface of the seven planets, but the daytime skies would never get brighter than Earth’s skies just after sunset, suffusing the world in a salmon-colored light,
Good luck doing much photosynthesizing with that.
It would be significantly brighter than the light in most of the photic zone beneath the seas and lakes of our world. This zone supports plenty of photosynthesis, thanks to accessory pigments.
But this does mean that the life-supporting zone in the water of these worlds would be much shallower.
Here’s Andrew LePage on the ‘habitability’ of these worlds.
As usual, Andrew dispels some (newly-minted) myths about these exoplanets; the best candidates aren’t d,e and f, but rather e,f, and g.
Exciting stuff.
In the Star Trek: TNG ep. “Conspiracy”, a clandestine meeting of Captains occurs on an abandoned tidally-locked planet Dytallix-B.
Funny, the planet has no indigenous life forms…including photosynthesizing plants…and yet there is breathable oxygen. :dubious:
Grasping at straws here …
Once the planet surface has oxidized all the exposed rock and the ocean has reached equilibrium oxygen saturation, then whatever atmospheric oxygen is left will just sit there. That’s implausible on an actively volcanic young planet, e.g. primordial Earth. It might well be plausible on an elderly static world.
The part I have problems with on a tidally locked planet is having any atmosphere at all. IMO it’d freeze out pretty quickly on the dark side and boil off on the bright side.