Why not the moon?

[ivog]

Has anyone watched "Man vs Universe part 3" aired on sci-fi channel aug 27th? It's about Mars and I think Elon is interviewed. I seem to be unable to find it online. Its available on Amazon but it looks like it's not available for the netherlands.

 

[donv]

There is also a pretty decent case to be made for Venus. No, not the surface, but rather the upper atmosphere. In the upper atmosphere of Venus, the temperature and pressure are very close to what we have on Earth. Even better, breathable air is a lifting gas on Venus, so it's not that hard to stay in the upper atmosphere.

 

[flashflood]

There is also a pretty decent case to be made for Venus. No, not the surface, but rather the upper atmosphere. In the upper atmosphere of Venus, the temperature and pressure are very close to what we have on Earth. Even better, breathable air is a lifting gas on Venus, so it's not that hard to stay in the upper atmosphere.

I can't help wonder whether Venus is a better candidate for terraforming than Mars. Anything we sent to Mars would just die. But if we sprayed a whole boatload of plankton, various critters that live near hydrothermal vents, and Deinococcus radiodurans at Venus, would some handful of them land in a survivable niche, evolve, and colonize the planet, gradually turning CO2 and sulfuric acid into oxygen and water and other happy things? I don't have any specific theory, just the observation that microbial life on Earth seems remarkably robust and adaptable.

 

[Skotty]

I can't help wonder whether Venus is a better candidate for terraforming than Mars. Anything we sent to Mars would just die. But if we sprayed a whole boatload of plankton, various critters that live near hydrothermal vents, and Deinococcus radiodurans at Venus, would some handful of them land in a survivable niche, evolve, and colonize the planet, gradually turning CO2 and sulfuric acid into oxygen and water and other happy things? I don't have any specific theory, just the observation that microbial life on Earth seems remarkably robust and adaptable.

I've wondered that myself. What would it take to terraform Venus? You can build pressurized habitats on Mars, but you're not a super cool galactic species unless you can terraform it to make it liveable. From that viewpoint, might it be easier to remove atmosphere from Venus than it is to add atmosphere to Mars? And might it be more maintainable once it' done? I can't help but wonder what hidden potential Venus may hold. It's closer to Earth size and might would have reasonable temperatures if the atmosphere was significantly modified. I dare would bet it has better resources too.

Of course, before we go terraforming planets, we probably need a one world organization or ... dare I say ... governing body ... to make such decisions at the solar system level.

 

[Cosmacelf]

Of course, before we go terraforming planets, we probably need a one world organization or ... dare I say ... governing body ... to make such decisions at the solar system level.

That would guarantee it would never get done. Eg. Space shuttle versus private company SpaceX. No, it takes hordes of entrepreneurs to do big things, not bureaucrats.

 

[ElSupreme]

There is also a pretty decent case to be made for Venus. No, not the surface, but rather the upper atmosphere. In the upper atmosphere of Venus, the temperature and pressure are very close to what we have on Earth. Even better, breathable air is a lifting gas on Venus, so it's not that hard to stay in the upper atmosphere.

I can't help wonder whether Venus is a better candidate for terraforming than Mars. Anything we sent to Mars would just die. But if we sprayed a whole boatload of plankton, various critters that live near hydrothermal vents, and Deinococcus radiodurans at Venus, would some handful of them land in a survivable niche, evolve, and colonize the planet, gradually turning CO2 and sulfuric acid into oxygen and water and other happy things? I don't have any specific theory, just the observation that microbial life on Earth seems remarkably robust and adaptable.

I've wondered that myself. What would it take to terraform Venus? You can build pressurized habitats on Mars, but you're not a super cool galactic species unless you can terraform it to make it liveable. From that viewpoint, might it be easier to remove atmosphere from Venus than it is to add atmosphere to Mars? And might it be more maintainable once it' done? I can't help but wonder what hidden potential Venus may hold. It's closer to Earth size and might would have reasonable temperatures if the atmosphere was significantly modified. I dare would bet it has better resources too.

Of course, before we go terraforming planets, we probably need a one world organization or ... dare I say ... governing body ... to make such decisions at the solar system level.

It is a lot easier to add heat energy to a system, than to pull it out. I mean the Sun is pretty good energy source. There aren't very many good heat sinks lying around.

 

[ItsNotAboutTheMoney]

It is a lot easier to add heat energy to a system, than to pull it out. I mean the Sun is pretty good energy source. There aren't very many good heat sinks lying around.

Not to mention that Venus' atmosphere is extremely high pressure and cloudy, which makes construction and solar power rather challenging.

Venus might have better absolute potential, but the process itself would be harder.

 

[Johan]

How impossible would it be to gradually move Venus from it's current orbit to a more earth-like orbit? I'm talking over time, perhaps using future technologies that may be able to extract large ammounts of energy with low cost, such as fusion or other yet-to-be discovered energy technologies.

 

[Skotty]

How impossible would it be to gradually move Venus from it's current orbit to a more earth-like orbit? I'm talking over time, perhaps using future technologies that may be able to extract large ammounts of energy with low cost, such as fusion or other yet-to-be discovered energy technologies.

I don't think the orbit of Venus is the problem. It's the atmosphere. Venus needs some serious atmospheric processing.

 

[Doug_G]

How impossible would it be to gradually move Venus from it's current orbit to a more earth-like orbit? I'm talking over time, perhaps using future technologies that may be able to extract large ammounts of energy with low cost, such as fusion or other yet-to-be discovered energy technologies.

That would be mind-bogglingly, ridiculously, absurdly, can't-come-up-with-sufficient-superlative impossible.

 

[Johan]

That would be mind-bogglingly, ridiculously, absurdly, can't-come-up-with-sufficient-superlative impossible.

Cool. So maybe wait a bit with that then

 

[ItsNotAboutTheMoney]

Cool. So maybe wait a bit with that then

Yes. It's a gradual process. Small asteroid, large asteroid, Mercury, Mars, Venus. Put everything back, and then repeat in a single shot for effect.

 

[rabar10]

We've gone off the orbital-mechanics rails here...

Here's an article published a bit over a year ago that addresses the original question: Mars versus the Moon (Issue #19) | Mars Society Education Forum

It touches on energy production methods, and several of the ISRU (in-situ resource utilization i.e. availability of water, oxygen, other raw materials) differences.

One it doesn't touch on is the availability of fuel with which to fuel rockets for return journeys. Methane has been detected in a few different location on Mars -- and it's surmised that this is one of several reasons that SpaceX is pursuing a methane-based architecture for its next generation of rocket engines.

 

[ElSupreme]

How impossible would it be to gradually move Venus from it's current orbit to a more earth-like orbit? I'm talking over time, perhaps using future technologies that may be able to extract large ammounts of energy with low cost, such as fusion or other yet-to-be discovered energy technologies.

I think this should be a good estimate. I am corsely rounding some numbers

Given (all from wikipedia):
Venus mass: 4.8676×10^24 kg
Sun mass: 1.98855×10^30 kg
Venus orbit: 108,000,000 km
Venus orbit velocity: 35.02 km/s
Earth orbit: 148,000,000 km (rough average)
Earth orbit velocity: 29.78 km/s
G: 6.674x10^-11 m^3 kg^-1 s^-1

g: G * (ms)/r^2

KE= 1/2 m v^2
PE (energy needed to escape gravity)= G (m1*m2) / (-r)


Current kinetic energy in Venus orbit:
0.5 * 4.9E24 * (35,000)^2 = 3.0x10^33 J (kg m^2/s^2)

Energy needed to escape Sun orbit from Venus elevation:
6x10^33 J (note this is double the KE of the orbit)

New kinetic energy in Earth orbit:
0.5 * 4.9E24 * (30,000)^2 = 2.2x10^33 J (kg m^2/s^2)

Energy needed to escape Sun orbit from earth elevation:
4.4x10^33 J (note this is double the KE of the orbit)


So at least 8E32 J of kinetic energy can be converted to the elevation.
But we need at least 1.6E33 J to raise the mass of Venus.
Net total energy input required to raise Venus orbit is 8x10^32 J. Or roughly 1/15th of the Sun's total yearly output.


EDIT: I did!

That would be mind-bogglingly, ridiculously, absurdly, can't-come-up-with-sufficient-superlative impossible.

EDIT 2:

And most likely we wouldn't be able to conserve the Kinetic energy, so it would likely take ~2.4x10^33 J to actually perform the maneuver. Or 3 times the previous estimate, which is 1/5 the Sun's total yearly output.

 

[Johan]

Great calculations ElSupreme! So when we transgress to a type II civilization (Kardashev scale - Wikipedia, the free encyclopedia) this would be quite doable.

 

[flashflood]

It is a lot easier to add heat energy to a system, than to pull it out. I mean the Sun is pretty good energy source. There aren't very many good heat sinks lying around.

Other than, you know, the entire universe, which is a vacuum at near absolute zero. Blackbody radiation is pretty efficient, as evidenced by Earth's failure to boil away after 4.5 billion years of solar cooking.

In the grand scheme of things, energy is much harder to come by. That's why Mars is so hopeless: it just isn't warm enough to sustain an atmosphere given its paltry gravity and distance from the Sun. Mars is like GM: you can keep it alive, but only by throwing massive external resources at it. It is not fundamentally self-sustaining, and won't ever be.

Venus, by comparison, is much closer to habitable. Only biology can achieve planet-scale terraforming, and biology works better and faster with an abundance of energy.

It turns out that people with actual official brains have considered this too. Check out Terraforming of Venus as a starting point.

 

[adiggs]

Other than, you know, the entire universe, which is a vacuum at near absolute zero. Blackbody radiation is pretty efficient, as evidenced by Earth's failure to boil away after 4.5 billion years of solar cooking.

In the grand scheme of things, energy is much harder to come by. That's why Mars is so hopeless: it just isn't warm enough to sustain an atmosphere given its paltry gravity and distance from the Sun. Mars is like GM: you can keep it alive, but only by throwing massive external resources at it. It is not fundamentally self-sustaining, and won't ever be.

Venus, by comparison, is much closer to habitable. Only biology can achieve planet-scale terraforming, and biology works better and faster with an abundance of energy.

It turns out that people with actual official brains have considered this too. Check out Terraforming of Venus as a starting point.

Fun link 'flash. Got me wondering:
http://en.wikipedia.org/wiki/Terraforming_of_Mars

And there's more - Europa. I be somewhere we could find a similar scale discussion for our moon.
http://en.wikipedia.org/wiki/Colonization_of_the_Moon

Good stuff

 

[woof]

Mars is like GM: you can keep it alive, but only by throwing massive external resources at it. It is not fundamentally self-sustaining, and won't ever be.

What a simile! But I wonder what it means for Elon's "Occupy Mars" T-Shirt if you substitute GM for Mars?