火星（Mars）南半球（southern hemisphere）地下的内部温度高出400°C

火星在数十亿年前曾拥有活跃的火山活动、磁场（magnetic field）和液态水。由于体积较小，其内部冷却速度远快于地球（Earth），导致了地质活动的停止。最新的研究探讨了火星目前内部的热状态。

The planet Mars is a cold and dry world completely devoid of life, but billions of years ago things were much different. This is when Mars had a much warmer interior than it does today, resulting in active volcanism that replenished its atmosphere, a magnetic field that protected the planet from harmful solar and cosmic radiation, and a surface of flowing liquid water. But due to Mars’s small size, the interior cooled far faster than Earth’s has cooled, leading to a loss of volcanism, near-absolute depletion of its magnetic field, and complete evaporation of all surface liquid water. But what is the interior heat of Mars like today?