# If 100% of the energy from the sun is reflected back into space

100% of the energy from the sun is reflected back into space, it's just shifted from a low-entropy state to a high-entropy state, and from a high frequency (ultraviolet) to a low frequency (infrared). But does the total number of photons change as a result? Are there more low frequency photons, then, in order to make the same amount of energy?

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Yes, if the planet is in balance, then, of course, it has to emit a higher number of photons that have a lower energy and lower frequency each because the energy of a single photon is related by $E=hf$ to the frequency. The entropy is essentially proportional to the number of photons, so it emits more entropy than it absorbs, and the entropy is increasing.