The primary light source is the sun for the planet Earth.
No, concrete does not absorb visible light and re-radiate it as infrared energy. Concrete reflects and scatters visible light, and it absorbs some of the heat energy from sunlight. This absorbed heat can then be released over time as infrared radiation when the concrete cools down.
It is a form of light that radiates from the sun.
That would be an outer layer called the, "Photosphere".
Moonlight is almost entirely reflected sunlight, with very small amounts of reflected starlight and earthlight as well. As such, it radiates at the same continuous spectrum as the sun, though it won't have the bright emission lines that the sun emits.
The Sun.
because it radiates heat
because it radiates heat
No, a red object looks red because it reflects red light while absorbing other colors. When white light containing all colors in the visible spectrum strikes the object, all colors are absorbed except for red, which is reflected off the object and perceived by our eyes as red.
-- You walk into the bathroom at night, turn the light on, and admire yourself in the mirror.-- The light bulb radiates light, which goes all over the place. Some of the lightreflects from your face toward the mirror, then reflects back from the mirror toyour eyes, and you "see" your face "in" the mirror.
Photosphere
Because at night it functions as a mirror for the sun. It's like this: You -------> (watch in this direction) ----> Moon (mirroring the sunlight in your eye) -------------------------------------- ..................^ Earth (blocks the sun) ............................../ .............................................................../ ............................................................/ ........................................................./ ....................................................../ ..................................................Sun (forget about the dots, that's just to position the lines because I can't type spaces in this drawing)