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If we were gonna develop a colony on mars would it be possible to explore geothermal energy and would it be viable?

(Assuming we could transport the required equipment)

Edit: Recently I found this video, where Elon Musk actually mentions geothermal. Could he have some knowledge we don't know about?

Elon Musk of SpaceX Introduces the Interplanetary Transport System

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    $\begingroup$ Very interesting question. +1. As far as I know this is currently up for debate with a tendency to "no". I'm really looking forward to the answers $\endgroup$ – Raditz_35 Jul 14 '17 at 12:01
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    $\begingroup$ This question does not appear to be on-topic for Worldbuilding.SE. It's too broad, and also is not really an 'imaginary world' question, but simply a real-world engineering/science one. $\endgroup$ – TylerH Jul 14 '17 at 16:04
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    $\begingroup$ Should it be called Martiothermal or Ariothermal energy? ;) $\endgroup$ – ypercubeᵀᴹ Jul 14 '17 at 19:45
  • $\begingroup$ I think solar based energy would be much more powerful. See Discussion of NASA/MIT MARS colony Energy Generation Study $\endgroup$ – user2259716 Jul 14 '17 at 21:47
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Mars has lost most of its atmosphere due to the lack of a magnetic field, protecting it from the stripping action of solar wind.

A magnetic field is thought to be generated by a high temperature core; therefore it is plausible to assume Mars has a low temperature core.

Since the core will be always warmer than the mantel and the crust. Also the lack of observed recent volcanic activity supports the conclusion that the martian crust is cold. So it's highly unlikely that we can harvest high temperatures from the first few hundreds meters of the crust.

However we could still use the crust as thermostat for application like cooling down or preheating process fluids. I think this still count as geothermal energy.

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  • $\begingroup$ There could be magnetism from a low temperature core if it was a ferromagnet. Iron and nickel, that are found in the earth core are ferromagnetic. But they do not occur in nature in ferromagnetic state. On the other hand, what if the core was made of magnetite? $\endgroup$ – user9981 Jul 14 '17 at 15:55
  • $\begingroup$ @Magicsowon But Mars doesn't have a magnetic field, we'd need an explanation for a hot core and a magnetic field, not a low temperature core and a magnetic field. $\endgroup$ – Azor Ahai Jul 14 '17 at 21:43
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Looking online, we have this. Take home point is that whilst we have a temperature gradient of 30-35K / km on Earth, Mars may have a gradient of 6 - 10K / km. That makes geothermal energy very hard to do.

But it's worse than that. On Earth, you extract Geothermal energy by pumping water through rock formations that are already saturated with liquid water. The same paper shows that this won't be the case in the upper few km of the Martian crust. So extracting what warmth there is there would be harder.

As L.Dutch said, you could use the crust as a constant-temperature source for ground source heating/cooling, but actual geothermal energy is probably out of the question.

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  • $\begingroup$ The paper linked was written in 2001. Since that time, we have come to realize that there is far more water on Mars than originally thought, particularly in the subsurface. That doesn't make you wrong necessarily, but it DOES make geothermal pumping on Mars more plausible than that paper assumes. $\endgroup$ – Isaac Kotlicky Jul 19 '17 at 14:26
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There might be large natural nuclear reactors on Mars.
From https://www.hou.usra.edu/meetings/lpsc2015/pdf/2660.pdf

Previously, it had been hypothesized that Mars had been the location of large natural nuclear reactors[1,2], as are known to have occurred on Earth [3] This hypothesis was prompted by evidence of a large nuclear energy release in Mars past, and was considered the simplest hypothesis to explain the available data.

Natural nuclear reactors are concentrations of radioactive isotopes at concentrations high enough to undergo spontaneous fission. Some people think this happened or happens on Mars.

Those would be toasty warm and certainly suitable for producing geothermal energy. I would think they might be evident if someone made a heat map of Mars.

ADDENDUM: To be clear - I think building a colony atop a nuclear explosion is a poor idea. But if there are concentrations of fissile materials such that spontaneous fission happens in some of them, lesser concentrations should still have enough decay going on to produce substantial heat. Maybe steer clear of the really hot ones...

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One more detail, Earth's crust is much more active than Mars' because we have a (huge) Moon. The thermal energy that keeps the core liquid and generating Earth's magnetosphere comes from Earth's spin relative to the Moon. Moon's gravity field creates resistance on Earth spin -- called tidal force -- slowly halting it, so that eventually it will be tidal locked to the Moon (as Moon is locked to Earth, and Mercury is locked to the Sun). The heat that maintains our liquid core comes from the friction of this halting. So we have our thick atmosphere thanks to the magnetosphere, that we have thanks to the Moon.

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    $\begingroup$ I think you're way overestimating the contribution of the moon to the Earth's heat budget. According to Wikipedia, "estimate of half of the total Earth internal heat source being radiogenic." $\endgroup$ – Cody Jul 14 '17 at 18:33

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