Just like most objects on Earth, lunar rocks do not emit any form of light at all. There is nothing on the Moon at all that attributes to its brightness in the sky. Without some help from another source, our celestial neighbor would be just another dull, lifeless orb in the Solar System. Every tiny bit of light that comes to us from our rocky satellite does not originate there.
Just as our Earth receives light from the Sun, so too does the Moon. The Moon, however, is a really bad mirror. Any known object in the Solar System either emits light like the Sun or reflects it. This holds true for the Moon as well.
When astronauts reached the Moon for the first time, they discovered the surface was quite dark. This has left the lunar surface far from smooth, with countless craters, mountains, trenches, and volcanic remains. This scale ranges from 0, meaning an object is pitch black, to a 1, meaning the object is incredibly bright and reflective.
Our Moon sits at a 0. Examples include campfires, light bulbs, candle flames, and computer screens. In terms of astronomical bodies, stars are the main objects that create significant amounts of visible light, and therefore are some of the brightest objects in the universe. If a planet somehow became large enough to initiate nuclear fusion and begin glowing, it would no longer be a planet. It would be a star.
Since planets and moons do not emit light, the only reason we can see them is because they reflect light from some other source. The strongest source of light in our solar system is the sun, so usually we see planets and moons because they are reflecting sunlight. The amount of sunlight incident on a moon or planet that gets reflected depends on the materials in its surface and atmosphere as well as its surface roughness. Snow, rough ice, and clouds are highly reflective.
Most types of rock are not. Therefore, a planet that is covered with clouds, such as Earth or Venus, is generally brighter than a rocky moon or planet that has no atmosphere. There are two main types of reflectivity: specular reflectivity and diffuse reflectivity. Specular reflectivity measures how much of the incoming light gets reflected by the object in the direction given by the mirror angle.
In contrast, diffuse reflectivity measures how much light gets reflected in all directions. A mirror has high specular reflectivity and low diffuse reflectivity. In contrast, sand has low specular reflectivity and high diffuse reflectivity. In everyday life, we experience specular reflectivity as the perception of mirror images and glare spots on the surface of objects.
We experience diffuse reflectivity as a somewhat uniform brightness and color that exists on the surface of the object and is roughly the same no matter what our viewing angle is. Many objects display significant amounts of both specular reflectivity and diffuse reflectivity. For instance, a red polished sports car looks red from all angles because of its diffuse reflectivity, while at the same time displays bright spots of glare because of its specular reflectivity.
The moon is not like earth, instead of a hot core, the moon is completely cold and dead. One thing that the moon does do is that it has an orbit around the earth. The reason that we see the moon with a glow or shine, is because the light of the sun is reflecting off of the moon that is visible to us.
Think of the moon as a mirror. The amount of light that gets bounced back to earth also depends on the time and place of the orbit of the moon. It appears larger and brighter and we can usually see the man-in-the-moon face really clearly. As the orbit changes, the angle of the light changes and less and less light bounces back to earth.
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