Why Does The Moon Shine?

Have you ever though about why does the moon shine? The fact is that moon is actually very Dark. We should not be able to see it all. Also unlike what the ancients thought the moon does not produce its own light. The answers to these questions are actually very interesting once you think about them. The Moon shines because it actually is a mirror but it a most interesting mirror when you get into it.

The general answer most people know about why the moon shines is that it reflects the light of the Sun. This is basically true. The moon basically bounces or relays sunlight from the Day side of the Earth to it’s night side. This of course alters as it orbits the Earth and gets near the side of Earth where the Sun shines from. This is what makes the moon appear visible

during the Day. The changing of the Moon’s phases is also a result of how we view the light reflected off of the moon. Half of the moon is always lit up by the light of the Sun it is simply that the moon is orbiting us that the amount of that lit portion changes as the month goes by.

The real mystery is why does the moon reflect at all. Like most objects in space, the Moon possesses a reflective characteristic called albedo. Albedo is how well an object reflects light. This characteristic seems pretty straight forward. Material like ice and snow have very reflective albedos. Land and Greenery have very low reflective albedos. What makes the moon so interesting is that it has the same Albedo as coal. That means that it has almost no reflective quality up close. So when the Apollo mission were going on the Moon was actually a pretty dark place. This only makes sense because of the large lava plains that it has.

The reason why the moon still seems so reflective is because of an interesting effect called the opposition effect. The opposition effect basically states that certain types of non reflective surfaces lose their shadows when directly in the line of sight of the light source shining on them. This why a road at night lit by head lights will seem to brighter than it is. The reason that moon does this so well is the loose regolith that covers most of its surface. The opposition effect is strongest for the moon when it is directly in the opposite position of the Sun in relation to the Earth.