^
But that's only if it came from Mars.

huggle wrote: ↑

Mon Jan 06, 2020 10:02 am

Oh, I love his sweater!

NASA has found Earth 2!*







*Meaning it's 20% larger and a bit of a sun-grazer.

I saw this on CNN today, but this article is more detailed. I was thinking that this is about the tenth time they've found the first Earth-like planet, but they're talking specifically about TESS.

But this looks really promising, although the stats raise a lot of questions. If it receives 86% of the solar energy that Earth receives, that implies that it's kind of chilly-- but if the star is a Red Dwarf then that energy is probably more weighted toward the infra-red, which may compensate. I also wonder what the apparent diameter of the star and the other two planets are from the surface. It sounds like the mini-Neptune would cause a solar eclipse every month or so. I also wonder how the proximity of a gas giant would effect the tidal locking. The place would have a very interesting sky, in any case.

^ Plus, doesn't one side of this planet always face the sun? That side might be too hot and the other perpetually dark side might be too cold. I can imagine people living in the Goldilocks zone near the edge of the dark side.

It's hard to tell how the tidal locking would affect the environment. The only tidally locked world we know about it Venus, and that has a runaway greenhouse effect. An Earth-like world with a transparent atmosphere and massive oceans may be better able to distribute the heat, although it would likely have monstrous winds. But that's why I wonder about the gas giant in the middle orbit. Given the great disparity in their masses and the frequent conjunctions, the giant's gravity may keep the planet spinning.

Actually Venus isn't tidally locked, but it's rotation is very slow. Whether that has anything to due with its current condition is an open question.

Now it's not tidally locked? First Mercury was locked and Venus wasn't, and then it was the other way around. I just can't keep up.

I'd love to know if either the slow rotation (or tidal lock) or the lack of a satellite has anything to do with runaway greenhouse effect.

It's actually rather hard to study planets closer to the sun than us. Venus especially since it's covered in clouds. The slow rotation and lack of a moon might play a role in it's current state. Personally I've wondered if it got hit by something big in the past, altering it's rotation.

Could be. That happened to us, so it could have happened to Venus, too, only with the opposite result.

Doesn't having a nearby gas giant come in handy for steering comets and asteroids away? I think I heard somewhere that Jupiter serves this function for us.

^Yeah that's one of the theories out there, along with it steering comets here to give us water. Sometimes both theories are lumped together. But I refer to those as "Miracle Theories"- IE, "We wouldn't be here except for (fill in the blank)".
The Jeans-Jefferys hypothesis was a variation of a Miracle Theory as was the notion that only singular stars (like the Sun, thus rare) could have planets.

Yeah, I find the Mediocrity Principle much more believable than Miracle Theories. I don't really buy into any theory that has Jupiter contributing heavily to life on Earth. I think there's a much more basic set of elements involved.

And in the case of exo-planets the Mediocrity Principle has been borne out.

Yup, wherever dirtballs can clump together, they will.