Real answer: the Sun emits most of its light in the visual region. By Wien's displacement law[0], the wavelength emitted with the most intensity given the Sun's

Real answer: the Sun emits most of its light in the visual region. By Wien's displacement law[0], the wavelength emitted with the most intensity given the Sun's 5778 K surface temperature is 501 nm, which is bang-smack in the middle of the visual spectrum, and is a light greenish-blue. Our eyes are more adapted to around 530-550 nm (which is more precisely green), because of two reasons: we evolved from fish, which lived in the ocean, where blue light is scattered (and thus green-red sensitivity is more important), and secondly, the atmosphere also scatters blue light, thus making sunlight more red. [0]: https://en.wikipedia.org/wiki/Wien%27s_displacement_law https://en.wikipedia.org/wiki/Wien%27s_displacement_law