Theoretically, if we could build a solar cell or more generic energy absorbing cell with no range or efficiency limits, what would be the total energy input available to it here on Earth?
According to wikipedia, “At solar noon on a clear March or September equinox day, the solar radiation at the equator is about 1000 W/m².” It seems like the average cost effective solar panel is hovering around 15% efficiency. I’m wondering a few things:
Is this the total amount of energy coming from the sun, or is this just energy in the visible spectrum? If so, what is the total amount of energy including all frequencies coming from the sun under the above conditions?
Besides the energy coming from our sun, what is the total (photon based) energy input to the Earth (W/m²) from all other sources (other stars and galaxies, background radiation, terrestrial radiation, etc.)? How about non-photon based? What is the total amount of energy hitting the earth from the weak, strong, and gravitational forces? Anything else I should be thinking of?
So we have a device that is absorbing energy. But really it’s capturing one particle (photon) and somehow transforming it into another particle (electron). This may be beyond the scope of this post, but now I’m a little confused about the whole matter/energy equivilance thing. What’s the difference between mass and matter and matter particles (quarks? protons? neutrons? electrons?), and also between energy, forces, and energy particles (photons? electrons? gluons? gravitrons?)?. Could a whole molecule or larger object be considered a really low frequency wave and be absorbed like a photon by an energy device receptive to that range of frequencies?
I’m not sure about anything else, but I’ll point out that this isn’t true. Generating electrical current is not the same as making electrons. The electrons were already there… all of them, in the solar cell and the wires and anything else that’s in circuit. All you’re doing when you’re generating current is making those electrons move in energetic ways.
As far as M-E equivalency, that’s a little harder to explain. Generally, if you’re converting solar power into chemical or nuclear potential energy, that’s really the same thing as converting it into mass… ie, into extra matter. If you’re using your solar cell to charge a battery, say, the battery is minisculely heavier when it’s fully charged than when it’s empty, because energy has been converted into mass. But there aren’t any new particles of matter, any new protons or neutrons in the battery, or even electrons. The existing particles have just been combined together in ways that their mass is greater. (Mass is not entirely a constant when it comes to subatomic particles.)
The total energy density of sunlight at Earth orbit is about 1366 W/m[sup]2[/sup]. Some of it is absorbed by the atmosphere; the exact amount depends on altitude, weather conditions, humidity, etc. 1000 W/m[sup]2[/sup] sounds about right for sea level. It makes little difference whether you include energy outside the visible spectrum; UV and everything higher is mostly absorbed by the atmosphere, and there isn’t that much IR and radio waves.
It’s negligible as a source of energy.
Forces don’t carry energy, waves and particles do. Gravitational waves are so weak that we haven’t even detected it, let alone use it as an energy source. Neutrinos are almost as bad - very difficult to detect, let alone use. There’s also solar wind and cosmic rays, but none of these carry a useful amount of energy.
There’s also not much UV or higher, either. Most of the Sun’s energy output is in the visible range of the spectrum. If you went above the atmosphere to capture the extreme UV, X-rays, etc., you’d get a bit more energy, but not all that much.
The difficulty of detection of gravitational waves and neutrinos is not entirely due to the low energies involved, but more to the fact that gravity and neutrinos both couple very weakly to matter. But the OP is positing a collector with no efficiency limits, so I think we can fairly assume that it’s (somehow, magically) capturing all of the neutrinos, gravitational waves, and other weakly-interacting particles hitting it. For neutrinos, the total amount of energy would still be negligible (slightly less than the energy in the cosmic microwave background, which is far less than the energy from distant stars, which is far, far less than from the Sun).
For gravitational waves, it would probably also be very small, but having not yet detected them, we can’t say just how small: It’s conceivable (though probably very unlikely) that the Universe is full of very large numbers of small, colliding black holes, say, in which case the total energy hitting the Earth in gravitational waves could be almost arbitrarily large.