Comment by rpozarickij
2 days ago
> Solar power is now growing faster than any power source in history, and it is closely followed by wind power—which is really another form of energy from the sun, since it is differential heating of the earth that produces the wind that turns the turbines.
It's interesting to realize that the vast majority of the energy used by humans comes from the sun (with the exception of nuclear and geothermal energy). Even hydro power comes from the sun, because the sun evaporates the water which then becomes part of rivers or other water reservoirs that power hydroelectric generators.
At some level all fossil fuels come from the sun. Fossil fuels come from biomass accumulated over millions of years. The energy that went into gathering all that carbon and hydrocarbons came from the sun.
Take it a step further and nearly all our energy comes from nuclear fusion, with the exceptions you noted.
I refer to my solar panels as nuclear power, just to mess with people:
I use a gravitationally-confined fusion reactor, and pull power out of it by allowing the radiation to excite unbound electron-hole pairs in a semiconductor substrate. It's dangerous; even miles away from the reactor itself I can't expose myself to the radiation for too long or I get a painful skin reaction, and that might lead to cancer someday, but hey, it's cheap and quiet and I don't pay for the nuclear fuel!
> I refer to my solar panels as nuclear power, just to mess with people
Solar is actually fusion power, which is way cooler than any fission plant that puny humans have ever constructed.
Tidal power doesn't come from the sun either. It slows the earth's rotation by a tiny amount.
Is the origin of that rotation not also the gravitational wells created by the Sun?
IIUC it's only half from the Sun's gravity well, the other half of that energy gradient is from the Moon's gravity well.
Also IIUC "energy from the sun" is really shorthand for "Energy emitted by solar fusion", which tidal would not involve.
The laws of gravity are entirely symmetric, so it doesn't seem fair to attribute it specifically to the sun; also, the energy in this case is coming out of the "v" in earth's good old 0.5mv^2 kinetic energy relative to the sun.
Good pedantry, but then we can argue that the origin of fossil fuels is geothermal (if we ascribe the origin of life to hydrothermal vents).
All fossil fuels also come from the sun!
I wonder if there are some minimal fossil hydrocarbon deposits somewhere that originate from chemosynthesis-only microbe populations.
The nuclear fuels are also probably from the Sun. Pretty much everything is the Sun.
Hm, no, don't the heavy elements used for nuclear fission come from a previous generation of stars?
They came from some other suns, technically.
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No wonder people worshipped the Sun in ancient times!
I clicked to the comments to see how far down this observation would appear. It was my first thought, although I can understand why the more energetic discussion is around human-centered energy collection and management.
Nuclear comes from the supernova that created all the heavy elements in our solar system. Fission is releasing energy trapped during that event. So from that standpoint, even Nuclear is solar in origin.
Well the sun didn't make those elements. Some other star did so they aren't solar. Also by that logic everything that is not a hydrogen atom would be "solar" so I don't think we can stretch the analogy.
Helium and Lithium were also created in the pre stellar era of the universe, hydrogen was the majority by far but not the only element that wasn't created in stars. I think anything past 3 on the periodic table is exclusively stellar though.