Submitted by mr_greenmash t3_11six1y in askscience
Edit to add: I guess a lot is reflected, but some warms land/air/oceans, some is used to generate electric energy, some is used for plant growth... But the energy also need to go somewhere. We can't just receive solar energy, and not let any go?
Does hest just slowly radiate into space? And how would that work? Transferring heat to a vacuum seems impossible.
99.99??% of this energy is reflected or reemited by earth
The problem is that this tiny fraction can eventually increase the total energy inside earth. Depends on how well earth can radiate energy.
But ideally we let it all go except for a tiny fraction that builds biomass. Basically every form of energy on earth available to humanity or not comes from the sun’s energy.
>Basically every form of energy on earth available to humanity or not comes from the sun’s energy.
Two significant exceptions come to mind:
Nuclear energy does not come from the Sun.
Geothermal energy is not powered by the Sun.
Heat can be transferred in four basic ways: conduction, convection, advection, and radiation. While the first three require a medium, radiation can travel through a vacuum.
All objects will emit thermal radiation at an intensity and range of wavelengths dependent on their temperature. Earth’s thermal radiation is infrared.
Heavy nucleus were forged in a Star. Not ours though
Geothermal energy is basically gravitational energy from the formation of the solar system. Also related to the sun.
Oddly enough you can somewhat argue about both of these, as billions of years ago the gravitational effect of what would become the sun had a significant impact in getting that energy into what would become the earth... or that nuclear energy comes from isotopes formed from previous stars. It just becomes a matter of definitions at some point though.
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Just to add: the thing you want to google to learn more about this is "black body radiation" or "thermal radiation."
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Is it you, Lord Kelvin ?
The heat inside Earth comes from the radioactive decay of, well, radioactive elements inside.
It is true that the accretion of a planet releases a lot af heat, but without the radioactivity, the Earth would have cooled in less than a billion year.
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In addition to reflected energy, most of the energy that gets soaked up on the light side of the planet continues to get radiated away during the night. That sort of balances it out. Then, depending on how well the atmosphere is capable of insulating Earth (increasingly well due to build up of aptly named greenhouse gases), the planet settles into an equilibrium state and that's the temperature we experience on average.
viscence t1_jchxkmb wrote
The sun manages to transfer heat through a vacuum just fine -- radiatively, by emitting photons of light. That is also how the earth loses heat. Like the sun, the earth has a temperature and therefore glows, radiating away heat. The earth is a lot colder than the sun, so it radiates much less, and invisibly in the infrared.