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[smjjames]

Also, a tidally locked planet wouldn't necessarily have its atmosphere snow out. Venus experiences days longer than its years, yet its atmosphere essentially rotates approximately every 4 Earth days. Thermodynamics drives global winds from the warmer day side across the cooler night side and back.

A planet experiencing such constant, strong global winds presents challenges of its own to life, but not insurmountable I think.

Life always finds a way. The permanently dark side would also pose it's own challenges to life and the winds coming from the day side would make some of it warm enough for life to survive there.

[Max™]

Hell, this system is so young and in such a dense neighborhood that it's hard to know how things like bombardment cycles will work out, was there a wisp of cometary material that already got stolen/kicked inwards, is there stuff out there which is falling inwards as we speak, are there moons and asteroids getting chucked across the system, at this age the Earth still had issues with fucking magma raining out of the sky from the big cloud that the moon was coalescing from as I recall, who knows what interesting shit is happening over on TRAPPIST-1 right now?

Also, a tidally locked planet wouldn't necessarily have its atmosphere snow out. Venus experiences days longer than its years, yet its atmosphere essentially rotates approximately every 4 Earth days. Thermodynamics drives global winds from the warmer day side across the cooler night side and back.

A planet experiencing such constant, strong global winds presents challenges of its own to life, but not insurmountable I think.

The surface pressure and sheer mass of the atmosphere itself means there isn't going to be much variation due to the small amount of sunlight making it through the cloud decks, unless you let the atmosphere relax and collapse down onto the surface it's going to fuckhot down there.

[wierd]

Semi-random question:

Since the planetary orbits are only meta-stable due to resonances, (implying that there is not a precise period of orbit around the star-- it speeds up and slows down due to said resonances) that should prevent tidal locking with the star, no? There is no reason for the rotational period of the planetary axis to stay perfectly synchronized with the solar orbital period, given the resonances in effect, right? The rotation might be very very slow, but not zero, i should expect.

[martinuzz]

Best chance is for one of the planets to have evolved supermassive hamsters, who keep the rotation going by using the planet as a giant treadmill.

[Max™]

What you describe at the end there is going to be a moon at L1 or L2 along a line with the planet and star, and the whole system has the moon/planet keeping the same face to each other and accordingly the star, unless it's a young doomed moon during inspiral, or perhaps a spin-orbit resonance besides 1:1 during the brief early era before it winds up getting locked into a 1:1 state.

[WillowLuman]

Hell, this system is so young and in such a dense neighborhood that it's hard to know how things like bombardment cycles will work out, was there a wisp of cometary material that already got stolen/kicked inwards, is there stuff out there which is falling inwards as we speak, are there moons and asteroids getting chucked across the system, at this age the Earth still had issues with fucking magma raining out of the sky from the big cloud that the moon was coalescing from as I recall, who knows what interesting shit is happening over on TRAPPIST-1 right now?

Also, a tidally locked planet wouldn't necessarily have its atmosphere snow out. Venus experiences days longer than its years, yet its atmosphere essentially rotates approximately every 4 Earth days. Thermodynamics drives global winds from the warmer day side across the cooler night side and back.

A planet experiencing such constant, strong global winds presents challenges of its own to life, but not insurmountable I think.

The surface pressure and sheer mass of the atmosphere itself means there isn't going to be much variation due to the small amount of sunlight making it through the cloud decks, unless you let the atmosphere relax and collapse down onto the surface it's going to fuckhot down there.

Just because the atmosphere might rotate like Venus' due to thermodynamics, doesn't mean it will be as thick

[Max™]

I figured you were talking about Venus, though I missed that it's only the upper atmosphere which rotates quickly, the lower atmosphere doesn't move anywhere nearly as much.

With a lighter atmosphere you would need much higher surface velocities and it's going to lose energy faster I'd expect.

But that doesn't answer my question. People are saying a tidally locked moon is impossible without L points, but a moon that's only tidally locked to the tidally locked planet, then it's able to orbit at any speed and distance (within reason, OFC), so long as its rotation matches up with its orbital period.

It'll need to be very close, the Hill Spheres (where the planet gravity dominates) of such a densely packed system aren't going to be very big, outside of those orbits the moon will be orbiting the star, to have it approach stability then you'd need to plunk it on the L1 or L2, but the rest of the system doesn't help this idea since it's got so many bodies in such a narrowly constrained system of orbits in the first place.

[sluissa]

So... SpaceX just announced they're gonna send two private citizens on a trip around the moon... Next year.

Hours beforehand, NASA announced they're considering putting people on their currently planned as unmanned capsule test around the moon... Next year.

Next year could be great.

[Egan_BW]

Hey look, the moon exists! We should do stuff with it!

[sluissa]

Hey look, the moon exists! We should do stuff with it!

For now, just look at it... from a distance.... a much shorter distance, but still a distance... but exciting nonetheless.

[Max™]

...and then: RKKV the fuck out of it, to show everyone who's boss!

[Sheb]

Hours beforehand, NASA announced they're considering putting people on their currently planned as unmanned capsule test around the moon... Next year.

Next year could be great.

That's amazingly fast by NASA standards. I wonder if Trump strong armed them to produce Great Stuff (tm)?

[Dorsidwarf]

That's crazy fast to how NASA usually rolls , considering that astronauts begin their mission brief, work through, training and practice months to a year in advance.

[LordBaal]

Well.. perhaps it's the right time for mankind to start being more bold, take more chances and Jumpstart a space economy somehow.

[MetalSlimeHunt]

In truth, a lunar orbit isn't all that much of a risk and is a known kind of mission, so it's not surprising they would just suddenly decide to do it. It's a decent test for the Orion capsule as well.

I mean, Apollo 13 had damn near everything go wrong when it was still a semi-fresh practice, and they made it back.