Does the Moon reflect light or emit light?
The Moon does not reflect sunlight! The Sun is illuminating the Moon and the surface of the Moon scatters and absorbs sunlight, but it doesn't reflect sunlight. A reflecting sphere throws a light beam directed at its center directly back over the same path as it came in on. A sunbeam directed at the center of the moon hits the surface of the Moon, there is no reflection. There is some absorption into the moon rock that is heating the moon rock up and making it emit predominantly invisible infrared radiation in all directions, the rest of the sunlight is being scattered into all directions and makes it possible to see the moon rock. The scattered light still has the signature of sunlight, i.e. the spectrum of sunlight, in stead of the absorbed sunlight that is reemitted at infra red, the signature of the moon rock. If the moon would truly reflect sunlight, we would not see the surface of the moon, just like we do not see the surface of a mirror, we see what is reflected by the mirror, so we would see a small image of the sun located halfway between the surface of the moon and its center.
The moon is made out of rock; it's actually made of pretty much the same composition as the earth.
As such, it can't glow, for the same reason the earth doesn't. It reflects light from the sun.
One way to check that, right here from earth: think about the phases of the moon. If the moon glowed, why would it be dark part of the time?
If you keep an eye on it, you'll see that the moon is only lit on the side of the sun, as in this photo:
Every visible thing emits light in order to become visible. If moon is ‘reflecting' light then just like a mirror, we should see image of Sun within moon. But it is not the case. Here I agree with the point raised in the answer by Ben Heideveld that "the Moon does not reflect sunlight! The Sun is illuminating the Moon and the surface of the Moon scatters and absorbs sunlight, but it doesn't reflect sunlight. A reflecting sphere throws a light beam directed at its center directly back over the same path as it came in on."
I also have similar opinion that I have explained in my following quora answer:
We do not see light itself. I have explained it at length in my upcoming book "Descriptive Knowledge, Mind and Reality - A case of Epistemological Realism".
Following I am copying relevant portion from this book:
1.6.5 How Mind Sees External Objects
Reality is also mathematics but not like this model assumption based mathematics. Model is a supposed closed system whereas reality is a real open system. Reality may not be foreseeable to mind but it is seeable to mind. We can see real objects only when they are within light field or waves created by a light source however some animals like bats may be able to ‘see' objects through sound waves. Light field is usually created by a glowing or luminous object and the presence of such a field induces a dull glow to the real objects that exist within the field. We do not see light field, we only see glowing objects that include source glowing object as well as all those objects who have acquired dull glow due to the presence of light field surrounding them. The apparently lighten up empty area before source glowing object or around visible dull objects is not the light field itself but consists of glowing concentration of molecules of atmosphere. To create a light field, all we need is a source glowing object may it be wild fire, a candle light, a light bulb or Sun. The field created in this way is usually a spherical outwardly spreading field such that outward flow is blocked by the presence of physical objects in the way. The resultant effect is that the light facing side of object acquires dull glow and becomes visible such that back side of object, though in theory should be devoid of light field but somehow acquires a darker shadowy glow. The reason for such a darker shadowy glow may be continuous interaction of those glowing molecules of atmosphere which are outside shadowy area with those of inside area who will acquire a down step secondary dull glow in this way.
Usually light field cannot cross through physical objects however to varying extents successfully passes through thin sheets of objects or transparent objects like glass etc. Interaction of light field with objects or even concentration of molecules within it is perfectly quantized and symmetrical. Mind is able to see moderately intense glow throughout to normal dull as well as darker shadowy glow and mind is able to capture a normal size range of those quantized symmetries of dull glow acquired by physical objects. But mind is not able to see the actual field of light. What seems right is that light itself has no visibility at all. Color of outer space is always dark regardless of the fact whether sun is visible or not. If color of light is white then color of space having visibility of sun also should have been white. At nighttime, we see moon with its reflected light in such a way that we do not see any ray of light coming to it from the direction of sun and what we see is only a bright moon with a handsome dull glow. The moonlight that we see around us in nighttime is not light of moon but the glow of concentration of molecules of our own atmosphere whereas any actual ray of moonlight coming from moon to our grounds is not visible. In a bright moon, we do not see reflection of sunlight rather we see light of moon's own dull glow. Normal visible objects become visible also not because of reflected light but as a result of their own dull glow that is acquired due to their presence in a light field. First of all reflected light should mean visibility of source glowing object by looking at the object which is reflecting light of source glowing object; example thereof is visibility of source glowing object in a reflecting mirror. Such a visibility of source glowing object through reflecting mirror would be attained by looking only from a particular angle. If we assume the meaning of reflection that light is coming from source glowing object but visibility of reflecting object is being reached to the observer then it would also be possible to be observed only from a particular angle. But actually the so visible object is visible from all the directions unless the view of object is blocked through other objects in the way. It is like after reflection, the original ray of light has lost the identity of source glowing object and has acquired the identity of reflecting object and then reflection of new identity is diverted towards all the directions. Now it is easy to realize that in fact it is not reflection rather it is acquisition of dull glow by the object that is present within a light field and this dull glow, just like original source glow, is visible from all the directions.