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Darkelement t1_iu1bkfy wrote

Reply to comment by Sierra-117- in A recently released set of topography maps provides new evidence for an ancient northern ocean on Mars. The maps offer the strongest case yet that the planet once experienced sea-level rise consistent with an extended warm and wet climate, not the harsh, frozen landscape that exists today. by Wagamaga

I guess it could be a misunderstanding, but what heat the mantle up in the first place? Would those forces not also create a hot core? Does this imply the core was never warm?

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Sierra-117- t1_iu1cvzm wrote

Well it takes a lot more energy to melt metals into liquid than rock.

Metal also has a higher rate of energy transfer. So the metal cools faster, and takes far more energy to stay hot.

The core is also more stable than the mantle, meaning is experiences less friction and therefore produces less excess heat.

The heat from the core will constantly radiate into the mantle, so the mantle is constantly gaining energy while the core cools. Because the core is HOT, just not hotter than we would expect under the given pressure.

Lots of factors, and there’s a lot more I could list! But basically it comes down to: the core has now cooled to a stable temperature, therefore the mantle has cooled to a stable temperature, therefore volcanic activity is likely to cease.

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TheLastForestOnEarth t1_iu1vvbd wrote

In Earth's case I believe one hypothesis is that the impact of two planets created Earth and its moon. The incredible heat of our core may simply be left over from this collision.

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goneinsane6 t1_iu26wio wrote

The primary contributors to heat in the core are the decay of radioactive elements, leftover heat from planetary formation, and heat released as the liquid outer core solidifies near its boundary with the inner core. This heat radiates/transfers to the mantle. Due to Mars' smaller size and the square-cube law, it has a higher surface area relative to its core and mantle (compared to a larger planet). This causes more heat to radiate out compared to the Earth and is the main reason why Mars' core is now mostly cooled. Mars simply cooled faster because it is smaller.

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