Eli5: How does the core of the Earth (or any planets) not cool and still give off tons of heat energy? Where is this energy coming from?
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Since space is mostly empty space, the process of losing heat is very slow. Typically heat transfer happens through conduction and convection, that is a warmer object is bleeding off heat to surrounding matter, which is typically a gas or fluid surrounding it. In space, this effectively doesn’t happen, since there’s very little matter in between bodies to transfer that heat to. So most of the heat is transferred through infrared radiation. This is a much slower process than the other two, and in the case of planets their cooled outer shell acts as further insulation which means that the rate at which a planetary body cools gets slower as the outside is cooling. In the case of Earth there’s even more insulation because of the atmosphere.
So the Earth is cooling, just very very slowly.
Since space is mostly empty space, the process of losing heat is very slow. Typically heat transfer happens through conduction and convection, that is a warmer object is bleeding off heat to surrounding matter, which is typically a gas or fluid surrounding it. In space, this effectively doesn’t happen, since there’s very little matter in between bodies to transfer that heat to. So most of the heat is transferred through infrared radiation. This is a much slower process than the other two, and in the case of planets their cooled outer shell acts as further insulation which means that the rate at which a planetary body cools gets slower as the outside is cooling. In the case of Earth there’s even more insulation because of the atmosphere.
So the Earth is cooling, just very very slowly.
I’d say the earths impact with the moon billions of years ago would be the attributing factor for the amount of heat it’s been able to hold in comparison to the other planets that are pretty much dead or dying
I’d say the earths impact with the moon billions of years ago would be the attributing factor for the amount of heat it’s been able to hold in comparison to the other planets that are pretty much dead or dying
The core is 19,400,000,000,000,000,000,000,000 kilograms. That does cool down if you give it a few billion years.
The core is 19,400,000,000,000,000,000,000,000 kilograms. That does cool down if you give it a few billion years.
I had also read that the pull of gravity by the moon and sun cyclically deforms the earth, creating internal friction that also contributes to added heating. Somebody more knowledgeable on the topic can expand on this.
I had also read that the pull of gravity by the moon and sun cyclically deforms the earth, creating internal friction that also contributes to added heating. Somebody more knowledgeable on the topic can expand on this.
As rest said, they cool off. Smaller planets cool off faster (still 100s of millions to billions of years).
That happened to Mars: core cooled, because of that magnetic field dissipated (no circling core to generate it), and that exposed surface of the planet to the Solar wind. It is assumed that is how Mars was stripped of water. Solar wind blew off atmosphere (no magnetic field to protect it), lowered pressure, water evaporated and subsequently was blown off as well.
It is stipulated that hot circling core and magnetic field due to that might be important for sustainability of the life on the planets. So smaller planets might not be good places long term as they cool off faster.
As rest said, they cool off. Smaller planets cool off faster (still 100s of millions to billions of years).
That happened to Mars: core cooled, because of that magnetic field dissipated (no circling core to generate it), and that exposed surface of the planet to the Solar wind. It is assumed that is how Mars was stripped of water. Solar wind blew off atmosphere (no magnetic field to protect it), lowered pressure, water evaporated and subsequently was blown off as well.
It is stipulated that hot circling core and magnetic field due to that might be important for sustainability of the life on the planets. So smaller planets might not be good places long term as they cool off faster.
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