So, Mars is a stubborn planet that refuses to be terraformed. No matter how much air you import in order to create a atmosphere around it, it will be blown away in a short time. And there is one simple reason for this-Mars has no magnetic field.

This is the reason why Mars's atmosphere is so thin, that it makes Mt. Everest feel like Venus, why it receives Chernobyl-level radiation, and water simply boils away, due to the thin atmosphere. So, there are multiple solutions to this, but the most common one is to install satellite that installs a artificial magnetic field in Langrangian Point. But there are multiple obstacles in this technique.

  • Supposing that the satellite was impacted by a small projectile (forget asteroids) which could be a micrometeor, a meteor or even space debris, it would careen out of the Langrangian Point, and our artificial magnetic field goes brrrr....

  • I cannot see how a small satellite can generate a large magnetic field. Strength does not matter, you need a really large magnetic field to shield it from solar winds, about thousands of miles wide.

  • The satellite would have to deal with ion accumulation on its poles, in other words, the formation of artificial auroras on it, which would produce electric disturbances which would make our magnetic field malfunction.

So, there is a alternate solution, and that is-

Making a dwarf planet Ceres orbit Mars

The idea here is simple. Ceres is nudged from the Asteroid Belt, and is forced into the orbit of Mars.

The trick here is to get Ceres into a highly eccentrical orbit around Mars. This configuration causes a lot of tidal heating to occur on Mars, and the core heats up, and forms an magnetic field. Then later, large quantities of oxygen, water and nitrogen are imported from the Outer Solar System, and are made to create an substantial atmosphere around Mars.

What are the drawbacks of this technique?

  • 3
    $\begingroup$ "It will be blown away in a short time": No it won't. I have no idea why some people believe that retaining an atmosphere around Mars is any kind of problem at human time scales. Over a geological time scale, yes, Mars as it is will have trouble retaining an atmosphere. Over a human time scale, it does not matter. Yes, it will lose maybe 1% of its atmosphere in a million years. Is that a problem? No, it just needs to be replenished every other million years. $\endgroup$
    – AlexP
    Commented Oct 23, 2022 at 16:18
  • $\begingroup$ @AlexP when a planet has been really terraformed, an Earth-like nature will develop as well. Grassland, forests, oceans.. wind and rain circulation.. why would a new atmosphere be "blown away" as the opener suggests ? it will reach some equilibrium with the planet.. and that should be designed properly, so no precious resources will get lost into space. $\endgroup$
    – Goodies
    Commented Oct 23, 2022 at 16:55
  • 2
    $\begingroup$ @Goodies: A small planet without a magnetic field, such as Mars, will lose its atmosphere in a few hundred million years. (Because some molecules move fast enough to escape, and because the pressure of the solar wind slowly but surely blows away the topmost rarefied layers. Little by little, over geological time spans all of it will be gone.) (Even Earth, much bigger and with a magnetic field, loses about 90 tonnes per year.) But for human purposes this is a non-issue; millions of years is a very long time, and nobody cares that every few million years the atmosphere needs to be topped up. $\endgroup$
    – AlexP
    Commented Oct 23, 2022 at 18:01
  • $\begingroup$ While the answers have given you the facts, I believe a natural extension of your idea is to take two Mars-like planets and put them in a binary-planet configuration to justify making both habitable (ignoring the time required to do this) and I believe that is well beyond suspension-of-disbelief. I like the idea. $\endgroup$
    – JBH
    Commented Oct 23, 2022 at 18:19
  • $\begingroup$ In addition to the magnetic field being unnecessary for keeping an atmosphere for human-relevant periods of time, the existing atmosphere already gives the surface of Mars a better radiation environment than Earth's magnetic field gives the ISS in orbit. An atmosphere thick enough to have a surface pressure of around 1 atm in Mars gravity would be an exceptional radiation shield. $\endgroup$ Commented Oct 23, 2022 at 23:34

2 Answers 2


If you can supply the energy to move a mass of $9 \times 10^{20}$ kg, maybe it is easier to put that energy directly into Mars rather than dragging planetoids around. Certainly it would be easier to heat habitats.

The Earth has a heat flux from the interior of about 47 terawatts (TW). Our moon provides about 3.3 TW (second answer). This is compared to 173,000 TW of solar radiation.

So our moon, which is very much larger than Ceres, provides less than 10% of the heat flux from the interior. And the heat flux is, on average, a tiny fraction of the solar radiation that hits the Earth. That is, it makes only a minute difference to global climate. The energy from Ceres would be much smaller.

Additionally, the heat from tidal heating gets distributed through the material of the planet. It takes a long time for that to get to the surface. So you would have to wait a disagreeable long time for any effect to happen.

So, to summarize:

  • Easier to do other things.
  • Minute effect.
  • Would take a very long time.

Ceres ($9\cdot10^{20} kg$) is 1000 times less massive than Mars ($6\cdot10^{23} kg$). If there is tidal heating, it's more likely that Mars will end up heating Ceres than Ceres heating up Mars.

If you want to use Ceres to heat up Mars and restart its core, you can either crash it, so that it will become a ball of molten rock with maybe even a proper moon (not the two rocky potatoes it has now), or, as stated in the other answer, use the energy you would need to move Ceres around to directly melt the core.

  • $\begingroup$ The core is already molten, it just doesn't appear to be producing powerful and organized convection currents supporting a dynamo, possibly because the surface and mantle are tectonically inactive, reducing the heat loss that drives convection currents. Smashing planetoids into Mars to remelt the entire thing might eventually restart the process, but would be the opposite of terraforming in every other respect. And of course the basic premise of the question is flawed...none of this is necessary. $\endgroup$ Commented Oct 23, 2022 at 23:30

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