Why is the moon bright very bright and other times dim?

Question

Obviously I have no backgound in astronomy but I always wondered why this was.

Answer 1

There are several contributing things.
First of all, there is the atmosphere. The more humidity, smoke, dirt etc. in the atmosphere, the dimmer the moon will appear. This is also what sometimes makes the sun appear dim.
The position of the moon in the sky also has an effect. The atmosphere is thinnest directly over your head than if you look to the horizon. So when the moon and the sun are overhead, the light encounters less atmosphere as it does on the horizon. This is why the sun and the moon often will have a red tint to them when they are first rising or setting and they are not so bright at those times.
Lastly, it also matters the time when you look at the moon. This is in two parts. Obviously, a full moon is brighter than a crescent moon. That is because the half of the moon that is lighted by the sun is mostly facing away from us during a crescent moon.
And also, the amount of sunlight in the sky makes the moon appear brighter or dimmer. This is because when there is still sunlight in the sky, you eye's pupil shrinks down to block the a lot of the sunlight out. But when night falls and you go outside for several moments, the iris in your eye opens up. When your pupil is dialated, you become "dark adapted' and your eye is more sensitive to light. The full moon that rises right at sunset is not really dimmer than the full moon that passes overehad at midnight, but because the light of the sun is no longer present, your eyes have switched to night-mode and this makes the moon appear brighter to you, not to mention that the full moon is overhead at midnight and has less atmosphere to penetrate.

Answer 2

Most of the reason is due to the suns position in the sky. Also, you need to take into effect things that might interfere with the suns rays reaching the moon; for example, clouds or dust storms in space. Also if there are fine or thin clouds in the way between your vantage point and the moon itself, these can reduce the visibility and the brightness of the moon in the sky.

Answer 3

The sun's positioning. The only reason we can see the moon is because of the sun shining on it.

Answer 4

clouds plat a major part and other atmospheric conditions.