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I have suggested that you could use antimatter to melt the core of Mars and restart the magnetic "dynamo", but it occurs to me that I never really considered exactly "how" you could do this. Melting the core of medium sized planets might actually be part of a far future tool kit to terraform worlds, so this is the sort of technology a space faring civilization would have.

Digging a shaft to the planet's core is out of the question, since the static pressure would collapse any conceivable tunnel long before you reach the core. So the question is "how would you go about melting the core of a planet". Antimatter is a convenient energy source, but I won't constrain any answers to just using antimatter, if you have a plausible, non magical means of melting the core of a Mars sized planet.

The Melting the Core question does seem similar, but most of the answers there either involve destructive heating of the entire planet or creating an artificial magnetic field without changing the composition of the core. I am looking at the idea as a way to solve several terraforming problems at once: generate a magnetic field, restart plate tectonics and the carbon cycle, recharge the atmosphere via volcanic outgassing and restarting the hydrological cycle as the crust warms up and the permafrost melts. The other difference is what technology or technique is needed to actually inject the energy to the core, something which is usually hand waved.

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marked as duplicate by Dan Smolinske, Vincent, Gilles, Jacobm001, Frostfyre Jun 6 '15 at 0:39

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ Do you want to melt it, or melt it and keep it warm for a long period of time? $\endgroup$ – Cort Ammon Jun 5 '15 at 3:58
  • $\begingroup$ That amount of molten iron would probably stay liquid for many millennia, but keeping it warm with additional inputs of energy isn't out of the question. The techniques to melt the core can always be pulled out again if it is cooling too fast. $\endgroup$ – Thucydides Jun 5 '15 at 4:07
  • $\begingroup$ Antimatter will obliterate Martian core together with its surface, unless Mars put on weight no amount of sweet talk can melt its heart. $\endgroup$ – user6760 Jun 5 '15 at 5:39
  • $\begingroup$ What is with all the negativity (literally) around this question? $\endgroup$ – Samuel Jun 5 '15 at 14:33
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    $\begingroup$ I did not feel the answers in the other thread answered the question in a satisfactory way. Here we have already seen at least two "out of the box" answers that provide nondestructive heating of the core: Neutrino/antineutrino interactions and using a micro black hole. I had hoped to see more answers like those. $\endgroup$ – Thucydides Jun 6 '15 at 2:46
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I'd ram the planet with another, smaller, planet.

BOOM

So long as the smaller planet was sufficiently large, and not moving fast enough to completely destroy Mars, this would deliver enough kinetic energy to liquefy the entire planet, including the core. This would also both increase the mass of Mars enough for it to support an atmosphere, and create one as a result of the increased volcanic activity.

Of course, inhabiting the planet in the immediate aftermath of this procedure may be a bit challenging, given the liquid nature of the surface, but the colonists are resourceful. I'm sure they'll figure it out.

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  • $\begingroup$ Inhabiting the planet afterwards can be quickened by dusting the molten planet with crushed asteroid. +1 $\endgroup$ – Henry Taylor Jun 5 '15 at 18:29
  • $\begingroup$ This would basically bring the planet back to an earlier stage of it's life and thus make it start over again. Given what we know or at least theorize about the forming of planets it would take millions of years for the planet to stabilize again. While technically a possibility, I don't think this would be prudent for Terraforming since the planet would be unavailable for colonization for thousands if not millions of years. I don't see a way of starting a self-sustaining colony there. I think you would rather want to start the core without turning the entire planet into a liquid ball of fire. $\endgroup$ – Sebastian_H Jun 6 '15 at 0:43
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If you don't want to wreck the planet with an impact crater, I'd go with tidal heating: put Mars in a close orbit around Jupiter for a few million years and let gravitational flexing do the work for you.

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Make a micro black hole and drop it in the planet.

A black hole has such high density that it can sink through iron as if it were a stone in water. The black hole will oscillate around the center of the planet and, after what may be several months (if ever), finally settle at the center (it'll be best to dig as deep as possible before dropping it in).

The black hole will be emitting Hawking radiation. Heating the planet. Some speculation exists on whether this is already happening in our solar system:

And if a black hole gets inside your planet? You get additional heat. This might account for unusual temperatures seen on Saturn and Jupiter, which are hotter than they should be from solar heating alone. A black hole inside the Earth might actually raise temperatures on the surface enough to sustain animal life long after the Sun dies out.

A power source that would last for eons, providing the most efficient possible conversion of matter to energy.

This research details the power output and lifetime of micro black holes. A black hole of about 200k tonnes will output around 1,527 petawatts in the beginning of its projected month long lifetime. That's over 20 times the solar radiation hitting the upper atmosphere of the Earth. You can drop in multiple black holes at different points in the planet to increase the power and energy distribution.

The black hole would not grow. It's only 0.6 attometers in diameter; that's subatomic in size. This means it doesn't fall into the Bondi accretion regime. A black hole must have an effective radii larger than atomic size for it to be able to capture more mass.

Several articles have discussed what would have happened if the LHC had accidentally created and released a black hole into the Earth.

The researchers point out that the slower the black hole, the less mass it accretes; so although it might pop out of the LHC and sink into our planet, it will suck up very little mass.

If it does evaporate, then near the end of its life, it will either explode or turn into a white hole, releasing any remaining matter in the center of the target planet. Alternatively, if it does grow, it'll happen very slowly (billions of years) and you won't have to replenish the core with black holes.

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  • $\begingroup$ What's your problem guys? This is science fiction. Are you familiar with this concept? $\endgroup$ – Samuel Jun 5 '15 at 7:41
  • $\begingroup$ Actually I like your idea of making use of high density but not gravity well, stellar BH will KO even our Sun and quantum BH is so insignificant that scientist is trying their hardest making one before it vanished like a blink of a virus eye. BH also obey laws of thermodynamic and must have temperature which you would prefer to call hawking radiation and these particles do no better than space lol. BH will disappear or evaporates but not before the end of time lol again. $\endgroup$ – user6760 Jun 5 '15 at 9:59
  • $\begingroup$ @user6760 I said micro black hole, not a stellar or quantum one. The mass can be planned so that its life time is anywhere from months to years. This is obvious. The rest of your comment doesn't make any sense. You should read them before posting. $\endgroup$ – Samuel Jun 5 '15 at 14:31
  • $\begingroup$ @Thucydides Alright, it seems few people are into the idea. Fortunately, it works as well with regular black holes, so whatever. I've included the power estimates. $\endgroup$ – Samuel Jun 5 '15 at 22:29
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Neutrinos. Specifically, neutrino-antineutrino annihilation. Direct two stream of particles straight down towards the core, one of neutrinos, another of antineutrinos. The streams will barely interact with the matter in the planet, but once the two streams converge, they'll annihilate each other. The resulting release of radiation provides the energy the liquefy the core.

This even lets you localize the heating, by controlling the angles of the streams.

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  • $\begingroup$ Neutrinos barely interact with anything, even each other. A beam of neutrinos and a beam of anti-neutrinos would work, but the efficiency would be so appallingly low that even options like "melt the entire planet and wait for the crust to cool back down" are better. $\endgroup$ – Mark Jun 5 '15 at 7:35
  • $\begingroup$ @Mark, do you have a source asserting that neutrinos don't interact with each other? In my (admittedly superficial) search, I couldn't find anything supporting either conclusion. $\endgroup$ – AmorphousCrystal Jun 5 '15 at 10:39
  • $\begingroup$ @AmorphousCrystal Analysis of the Neutrino-Antineutrino Annihilation from the Max Planck Institute looks good. The term to ask Google for is annihilation cross section neutrinos, and there are links on Physics.SE $\endgroup$ – JDługosz Jun 5 '15 at 19:27
  • $\begingroup$ In theory, they do interact, but the interaction cross-section is very, very small. $\endgroup$ – Mark Jun 5 '15 at 19:38
  • $\begingroup$ Annialation is the exact same phenomenon as pair production, and in both forms the rate it takes place is intimately related to the half-life of beta decay modes. It is very well understood as part of the standard model, and if you look up neutrino in the particle database you'll find every (primitive) thing there is to know about it. Annihilation cross section isn't in the summary table, but I'm sure someone could calculate the actual results for your proposed beams. Note that it depends on energy level, too. $\endgroup$ – JDługosz Jun 5 '15 at 19:45
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When an earth quake happens shock waves propagate through the planet. On earth it is thought to be possible to trigger earthquakes by building a dam and adding a lot of water to the wrong place

How this would apply to a geologically inactive planet like Mars I am not sure but given you have said we have anti matter to play with a Mars-quake or powerful shock wave machine needs to be built. Actually several. On opposite sides of the planet. The quakes/pulses will be timed so the shock waves from all the machines will meet in the core of the planet in such a way that they cause compression of the material there. This compression will cause heating.

If each shock wave can raise the temperature of the core by a small fraction of a degree this will accumulate over time and many shock waves. The shock waves will want to be as powerful as possible but not so powerful they destroy what ever machine is making them or do too much damage to the surrounding landscape. Though you could make that part of the world if you want.

Enough Mars quakes to bring the core up to the required temperature then you can move your colonists in. It would probably be pretty unpleasant being on the planet while the machines are running.

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  • $\begingroup$ Plate tectonic occurs due to convection of Earth's molten mantle, depends on how these plates meet new lands or trenchs form, the energy releases due to great fiction between plates will result in earthquake if Mars has a solid iron cores your hulk smash wouldn't cause enough fiction to ignite the core but depends on his anger management we wouldn't want too many near earth objects loitering around our vicinity lol. $\endgroup$ – user6760 Jun 5 '15 at 9:45
  • $\begingroup$ @user6760 quakes are probably the wrong word when dealing with planets with out molten cores. I've edited the answer to make it clearer what we want are the shock waves. We don't want to ignite the core just warm it up a bit. Lots of shock waves will probably be required, even a few fractions of a degree each time would accumulate. $\endgroup$ – Wil Selwood Jun 5 '15 at 10:10
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Disclaimer: melting planetary cores is expensive, widely considered rude (by the locals), and hazardous to your health.

...

OK, so you still want to melt it? This is going to be a big job, but you can make large quantities of antimatter, so you're probably capable of doing this.

Make a breeder reactor–a big one. You're going to want to gather all the uranium on the planet. You might need all of earth's uranium too, or you could synthesise lots of it, since you apparently have great enough mastery of physics to make planet melting quantities of antimatter. Dig a huge pit and place the uranium in it. Add a carefully calculated (left as an exercise for the reader at home) quantity of Pu-239 to get things going, then sit back and wait.

The Pu-239 will convert U-238 to Pu-239, generating more fuel than is consumed. This will eventually get hot enough to melt, then start melting its way through the rock. The reaction rate will increase as it descends because it's breeding more and more fuel. Eventually, you'll have a molten iron core with a load of radioactive materials keeping it warm, just like on earth.

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  • $\begingroup$ I like this idea, although it seems like it violates the Laws of Thermodynamics, but then I know nothing about breeder reactors. Can you provide some math? How much fissile material would you need? How much heat would be generated? $\endgroup$ – Joshua Hanley Jun 6 '15 at 0:18
  • $\begingroup$ @JoshuaHanley Do you mean because it produces more fuel than it uses? There's no violation there, it's converting heavy nuclei (U238) into fissile heavy nuclei (Pu239) which then fission. Similar to how people often stack logs around the fireplace, to dry them in preparation for burning. $\endgroup$ – frodoskywalker Jun 6 '15 at 0:26
  • $\begingroup$ You'd need absurd amounts of material, but we are talking about melting the core of a planet $\endgroup$ – frodoskywalker Jun 6 '15 at 0:27

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