"True Lies"

[Joshua Buffone]

Have you ever seen the movie "True Lies" with Arnold Schwarzenegger? If you have, you might know why Im posting this thread, if you havent, heres why.

 

In the movie, Mars is now inhabited by colonists from Earth and they live in oxygen supplied domes. Seems reasonable enough for a sci-fi flick.

 

Then movie basically states that all of Mars's core is a giant glacier that, once undergoing sublimation caused by an alien reactor, will release so much oxygen and life-sustaining gasses that Mars will have an atmosphere suitable for human life. WTF?!

 

This was more than far-fetched to me. I thought that if a planets glacial core went through sublimation, and then gas burst through the crust of the planet to make an atmosphere, wouldnt the planet then be hollow, and dangerously unstable? This would mean that the planet would inevitably cave in on itself! Right?

 

Ok, so heres the main purpose for the thread. Three questions:

 

Is a planet with a glacial core even possible?

(I think not, due to heat inevitably created in the center of the planet)

 

 

If you actually had a galcial core that went through sublimation and turned into gas , would it actually create an atmosphere for the now hollow planet? (I really think its unlikely, but maybe plausible?)

 

 

Would a hollow planet of Mars's size actually be able to sustain itself?

(I think not, since mountains and canyons would have no support underneath, thus statring a planetary cave-in)

 

I know alot was just Hollywood, but I do want to get to the bottom of these questions.

 

Sincerely,

Joshua Buffone

[Moontanman]

First, wrong movie, you are thinking of Total Recall. Second i don't think they asserted the entire planet was hollow but I would question just how big the hollow would be, probably no where big enough to cause the instability of the entire planet but since as far as I know there is no such reaction or substance as portrayed in the movie it is just science fiction after all.

 

But to be precise , no a Mars sized planet with an ice core is unlikely if not impossible but a Mars sized and massed planet with a rocky crust and an ice core is impossible.

 

No a hollow planet of Mars size and mass would not be stable.

 

If you actually had a galcial core that went through sublimation and turned into gas , would it actually create an atmosphere for the now hollow planet? (I really think its unlikely, but maybe plausible?)

 

Lots of depends upons here but I'll say no, the planet would not be stable and any atmosphere created would be made up of what ever the ice was made of.

[Joshua Buffone]

Your right about the movie name.

 

They did emply the whole core was subliminized.

 

I knew that the whole glacial core idea was impossible for a planet of Mars's size, but could it work on a small, distant-from-the-sun planet (I cant say Pluto, its not a plant )?

 

Is there any way a hollow planet can exist?

[Mr Skeptic]

Perhaps. Some of the moons are planet-sized, and contain a solid core of frozen material (eg water ice, not normal water ice but a different form that forms under very high pressure). I suppose it could be hit by space debris and somehow get close to the sun so that the sun can evaporate the volatile elements, leaving a frozen core surrounded by dust.

 

Not for mars though. For mars, the polar ice caps are made largely of CO2, which is considered a good target for terraform. The CO2 can be warmed up so that it could provide both atmospheric pressure, greenhouse effect to warm the planet, and a carbon source for plants (which would make oxygen for us). No need for a frozen core or such BS. Eventually (millions of years I think) it would lose the atmosphere again, due to its weak gravity.

[Joshua Buffone]

I can assume from your first paragraph, Mr. Skeptic, that glacial cores are hardly possible, nigh impossible.

 

I am confused how Mars would lose the atmosphere. I know that if it doesnt have enough gravity to kep something down, that something will fly away, but why would it take millions of years?

 

Is the whole oxygen-filled dome idea possible? Maybe if we used the carbon source from the warmed up CO2 to grow plants for creating oxygen for the domes? Would that be possible, or would we need to many plants?

[Moontanman]

I can assume from your first paragraph, Mr. Skeptic, that glacial cores are hardly possible, nigh impossible.

 

As would be a hollow core for any object large enough to be a sphere under it's own gravity.

 

I am confused how Mars would lose the atmosphere. I know that if it doesnt have enough gravity to kep something down, that something will fly away, but why would it take millions of years?

 

The atmosphere would not suddenly fly off into space, Gasses move at certain speeds at certain temps. If gravity is low enough the speeds can exceed the escape velocity but not all at once. Also solar winds slowly strip away atmospheric gasses, the lower the gravity the faster they strip away.

 

If you could instantly give the moon an Earth like atmosphere it would take a long time to escape. Given enough time even the atmosphere of the Earth strips away, much slower than Mars because the Earth has a protective magnetic field but strip away it will many billions of years from now.

 

Is the whole oxygen-filled dome idea possible? Maybe if we used the carbon source from the warmed up CO2 to grow plants for creating oxygen for the domes? Would that be possible, or would we need to many plants?

 

Yes it is possible, I'm not sure how long it will take to fill a dome up with oxygen from plants but there are chemical processes that can be used as well in a small space like a dome.

[Mr Skeptic]

The solar wind can blow away the atmosphere, but only very slowly. Solar wind is very weak due to its low density.

[Moontanman]

http://en.wikipedia.org/wiki/Solar_wind

 

Mars is larger than Mercury and four times farther from the sun, and yet even here it is thought that the solar wind has stripped away up to a third of its original atmosphere, leaving a layer 1/100th as dense as the Earth's. It is believed the mechanism for this atmospheric stripping is gas being caught in bubbles of magnetic field, which are ripped off by solar winds.[32]

 

 

http://www.astronomynow.com/news/n1003/15mars/

 

Mars is constantly losing small amounts of its atmosphere into space, but a new study shows that the loss rate may be enhanced by pulses of solar wind energy.

 

The researchers analysed solar wind data from the Advanced Composition Explorer (ACE) and Mars Express observations that track the flux of heavy ions leaving Mars' atmosphere, and found that bursts of atmospheric loss correlate with solar events known as corotating interaction regions (CIRs).