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If radiogenic heating is so important, why are Mars and Mercury not also geologically active? Mercury is only slightly less dense than Earth after all? Thanks
by marktangotango 8y ago
If radiogenic heating is so important, why are Mars and Mercury not also geologically active? Mercury is only slightly less dense than Earth after all?
Thanks for the response, btw, been waiting for a geologist ama for a while!
- cbkeller 8y agoSize - Mars and Mercury are both quite a bit smaller than Earth. So they lose heat faster for essentially the same reasons that your cells have to be small: smaller spheres have a higher surface area to volume ratio! While in neither case is diffusion the only process at work, it's a critical limiting factor in both cases. Diffusion of heat, diffusion of nutrients: it's all the same math!