I understand that the sun gives energy primarily in the form of sunlight, which contains various wavelengths of electromagnetic radiation. If the earth absorbs some of the energy, does the earth’s “total energy” accumulate?
In: Planetary Science
The first 5, 10 minutes of this video explain your misconception very well: [https://www.youtube.com/watch?v=DxL2HoqLbyA](https://www.youtube.com/watch?v=DxL2HoqLbyA)
So the earth loses as much energy as it absorbs from the sun, it’s balanced. Some energy is stored in bonds between matter, like plants and us, lots is lost as heat and radiation.
If the earth heald onto more energy than it released, things would get warmer until it got to a point where the energy leaving earth equaled the energy coming in.
The Earth radiates the same amount of energy out as it gets from the sun. If it didn’t, the temperature of Earth would quickly become too hot to survive.
When the light of the sun hits Earth, most of it bounces back without doing anything. Some of it heats Earth up, but that heat will eventually radiate away into space, so the long-term increase is nothing.
Earth actually radiates away 20X photons than it absorbs. That’s because processes on the planet (mostly life) will absorb and convert light to other forms of energy, then use it and generate heat. That causes it to radiate away over time in the form of infrared.
So the long-term net gain from the Sun to Earth is zero. The problem with climate change is that greenhouse gases make it harder for Earth to radiate away energy. That means more of the sun’s energy stays on Earth longer, which causes the planet to convert more highly organized energy into disorganized energy. That causes the temperature to increase while we wait for that energy to eventually radiate away again.
The process of converting highly dense and usable energy to less dense energy is called entropy. There’s a really excellent ELI15 (https://www.youtube.com/watch?v=DxL2HoqLbyA).
The total energy of the earth does not accumulate, at least not much. You can argue that some of the energy on the planet is stored chemically in plants and such, but most of it is just the thermal energy of the planet.
All objects that has a temperature emits radiation via blackbody radiation , however the amount of radiation per second depends massively on the temperature at a rate of T^4, this is called Stefan–Boltzmann law, so if you double the temperature(in kelvin) you get 16 times more radiation per second.
The earth is basically at an equilibrium, where the amount of energy it gets from the sun, is equal to the amount of energy that it emits. Think of it like this, the sun emits a ton of energy, but only a tiny tiny fraction hits the earth. Therefore the earth has to only emit a tiny tiny fraction of the suns energy to stay even.
If the sun started giving us more energy, the temperature of the earth would rise until it reaches the new equilibrium. Or if we emit a ton of greenhouse gasses which contains the radiation the planet emits meaning the planet now has to have a higher temperature to get into equilibrium and we get global warming.
yes, it’s called converting that energy into other things, like organic life. where do you think you get the energy output from wood burning comes from? organic life are for all intents and purposes are batteries. the energy humans get are ultimately from the sun.
The planet (on average) emits the same amount of energy it takes in, otherwise, it would eventually burn up or freeze over.
The Earth receives low entropy (concentrated) energy from the sun, and emits high entropy (dispersed) energy back into space as infrared.
A very interesting video on this topic was done by Veritasium. https://youtu.be/DxL2HoqLbyA?si=vf38I4KQ8kq_XQkH
Second picture has a good visualization of the sunlight cycle:
[https://mynasadata.larc.nasa.gov/basic-page/urban-heat-islands](https://mynasadata.larc.nasa.gov/basic-page/urban-heat-islands)
watch this for great content and explanation of exactly what you’re asking: [https://www.youtube.com/watch?v=DxL2HoqLbyA](https://www.youtube.com/watch?v=DxL2HoqLbyA)
In short: the exact same amount of energy received from the sun is radiated back out into space.
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