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NASA study reveals Venus crust surprise

science.nasa.gov

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Re: NASA study reveals Venus crust surprise

#51

Post by andrewflnr »

gamescr wrote: post #8
WalterBright wrote: post #2

I wonder if Venus could be terraformed via a sun shield placed in orbit around it. How big would it have to be to reverse the runaway greenhouse effect?

Part of the problem is having too much atmosphere. In the original Cosmos Carl Sagan talked about a hypothetical solution where we capture asteroids, and throw them at Venus in such a way that they just nick the atmosphere and knock large quantities of atmosphere out into space. One you reduce atmospheric pressure to a certain level, things could become habitable. Then throw in iron form the atseroid belt to react wi…

I recall one of the plans being to use the sun shield to entirely freeze out the atmosphere, then use a mass driver to chuck most of the CO2 into space. I don't recall exactly where that was supposed to be on the feasible to scifi spectrum.

I'd rather try to keep the carbon around for organic molecules. Are we sure we can't get in enough H2O and N to balance it out and build a nice thick biosphere?

Re: NASA study reveals Venus crust surprise

#52

Post by pfdietz »

andrewflnr wrote: post #51
gamescr wrote: post #8

Earlier quoted context omitted.

Part of the problem is having too much atmosphere. In the original Cosmos Carl Sagan talked about a hypothetical solution where we capture asteroids, and throw them at Venus in such a way that they just nick the atmosphere and knock large quantities of atmosphere out into space. One you reduce atmospheric pressure to a certain level, things could become habitable. Then throw in iron form the atseroid belt to react wi…

I recall one of the plans being to use the sun shield to entirely freeze out the atmosphere, then use a mass driver to chuck most of the CO2 into space. I don't recall exactly where that was supposed to be on the feasible to scifi spectrum. I'd rather try to keep the carbon around for organic molecules. Are we sure we can't get in enough H2O and N to balance it out and build a nice thick biosphere?

You'd have to shoot it out of the solar system, otherwise much of it would reaccrete onto Venus... or onto Earth!

Re: NASA study reveals Venus crust surprise

#53

Post by mseepgood »

lisper wrote: post #30
criddell wrote: post #25

Earlier quoted context omitted.

Does intelligent life mean only human-level intelligence? If we found a bunch of chimp-like animals running around, would that count as intelligent life?

Sure, but our interactions with chimp-like intelligence on another planet are unlikely to be substantially different from our interactions with chimp-like intelligence on this planet. It only gets interesting when both are more or less evenly matched, and that is extremely unlikely.

And our interactions with same-level intelligence on another planet are unlikely to be substantially different from our interactions with same-level intelligence on this planet. We've seen this before when people from one continent encountered those from another. In fiction, we show (via projection) how we might treat other intelligent life forms (every accusation is a confession).

Re: NASA study reveals Venus crust surprise

#54

Post by adrianN »

moron4hire wrote: post #45
BuyMyBitcoins wrote: post #14

Earlier quoted context omitted.

Then, move the MegaMaid into an orbit around Mars and go from suck to blow. Venus has too much atmosphere, Mars has too little. Win Win.

It wouldn't do Mars any good. Lacking a magnetosphere, any atmosphere you add will get stripped away by the Sun.

The atmosphere will be stripped away over a time period of millions of years though.

Re: NASA study reveals Venus crust surprise

#55

Post by cyberax »

dataflow wrote: post #31
cyberax wrote: post #23

Earlier quoted context omitted.

I've read a crazy proposal: 1. "Humidify" the atmosphere by crashing comets into Venus. This will also allow us to create a temporary "cloud" around Venus that can shield it from the Sun and lower down the temperature. 2. Once the temperature is low enough, Venus will get oceans on its surface. 3. At this point, CO2 can be split into carbon and oxygen. Oxygen will be immediately bound by the huge amount of under-oxid…

How many comets would you have to crash and how would one redirect and crash them that wouldn't make this exotic-level?

Depending on a size, probably on the order of tens of thousand.

Comets in the Oort cloud take very little energy to put on a collision orbit, the Sun barely holds them gravitationally, orbital speeds in the Oort cloud are measured in _meters_ per second. So they require (relatively) little energy to put them into a required orbit. It might be doable with just regular thermonuclear charges.

It will then take these comets more than a thousand years to "fall" from the Oort cloud.

Re: NASA study reveals Venus crust surprise

#56

Post by andrewflnr »

pfdietz wrote: post #52
andrewflnr wrote: post #51

Earlier quoted context omitted.

I recall one of the plans being to use the sun shield to entirely freeze out the atmosphere, then use a mass driver to chuck most of the CO2 into space. I don't recall exactly where that was supposed to be on the feasible to scifi spectrum. I'd rather try to keep the carbon around for organic molecules. Are we sure we can't get in enough H2O and N to balance it out and build a nice thick biosphere?

You'd have to shoot it out of the solar system, otherwise much of it would reaccrete onto Venus... or onto Earth!

I guess I'll count that as another reason to prefer managing it in situ. But it might be fine, actually? Slow re-accretion can probably be managed by whatever terraforming process we've kickstarted while most of it was gone.

Oh wait, I remember the plan, ship it to Mars so they can have some decent atmospheric pressure.

Re: NASA study reveals Venus crust surprise

#58

Post by hinkley »

andrewflnr wrote: post #51
gamescr wrote: post #8

Earlier quoted context omitted.

Part of the problem is having too much atmosphere. In the original Cosmos Carl Sagan talked about a hypothetical solution where we capture asteroids, and throw them at Venus in such a way that they just nick the atmosphere and knock large quantities of atmosphere out into space. One you reduce atmospheric pressure to a certain level, things could become habitable. Then throw in iron form the atseroid belt to react wi…

I recall one of the plans being to use the sun shield to entirely freeze out the atmosphere, then use a mass driver to chuck most of the CO2 into space. I don't recall exactly where that was supposed to be on the feasible to scifi spectrum. I'd rather try to keep the carbon around for organic molecules. Are we sure we can't get in enough H2O and N to balance it out and build a nice thick biosphere?

There’s a book where they freeze the atmosphere then cover the ice with a thick layer of dirt. But I cannot recall which.

Re: NASA study reveals Venus crust surprise

#59

Post by hinkley »

moron4hire wrote: post #45
BuyMyBitcoins wrote: post #14

Earlier quoted context omitted.

Then, move the MegaMaid into an orbit around Mars and go from suck to blow. Venus has too much atmosphere, Mars has too little. Win Win.

It wouldn't do Mars any good. Lacking a magnetosphere, any atmosphere you add will get stripped away by the Sun.

The estimate I heard is it would take 100,000 years for the atmosphere to be stripped off. That’s a long long time.

Re: NASA study reveals Venus crust surprise

#60

Post by hinkley »

gcanyon wrote: post #35
bdamm wrote: post #13

Earlier quoted context omitted.

That would require a lot of energy to ensure the gasses escape Venus' gravitational pull, which would in turn effectively be a rocket. So then we'd be adjusting to ensure we don't mess with Venus' orbit too much.

Venus outweighs its atmosphere by about 10,000 times. This is actually less than I thought -- for comparison Earth outweighs its atmosphere by over 1,000,000 times, which is still far less than I would have guessed. Venus's escape velocity is less than 1/3rd of its orbital velocity. According to google, Venus's orbit, despite being very circular, causes its velocity to vary by a KM/s from aphelion to perihelion. So I…

Spinning it up would be handy.
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