The moon is made up of large dark volcanic rock, and no offense to the moon, but the moon is not like the earth. Instead of a hot core, the moon is icy and dead. It doesn’t rotate or turn like the earth either, and it faces in the same direction. The moon is white or shiny because the Sun’s light reflects off the moon’s surface, making it visible.
The moon is made up of quite dark material. So it only reflects about 12% of the light that hits it. The amount of light that gets bounced back to earth also depends on the time and place of the moon’s orbit. When the moon’s orbit is directly facing towards Earth, a large amount of light bouncing back. Because there’s more of the face of the Moon facing the earth. It is called the full moon. What is the color of the moon? The moon appears brighter gray or white.
Why moon is white?
The moon is white because of the rocks that the crust is composed of plagioclase. Plagioclase is the mineral that makes up most of the crust. It is a common white mineral found in igneous rocks. Also, This rock has large plagioclase crystals in it. The moon’s whiteness, however, is because of the abundance of plagioclase in the crust. How is it that the crest of the moon contains so much plagioclase? To find out, you have to look for and a half billion years into the past.
Immediately after the moon formed, its entire surface was covered by an ocean. Instead of water, this ocean was made entirely out of magma. The moon four and a half billion years ago was covered in a magma ocean. All rocky planets were originally covered in magma oceans, including the earth. As the magma cooled minerals as plagioclase formed, it sank or floated in the magma based on their density.
The heavier minerals sank to the bottom while the lighter minerals like plagioclase floated to the surface. The plagioclase is grouped in this top layer to form the crust. It is how the surface of the lunar magma ocean crystallized into plagioclase-rich rock. The result is the white surface that we see today.
Scientific explanation: The moon can appear yellow, gray, orange, and other times, it appears white. So what’s going on? It’s the same process that makes the Sun sometimes appear in different sizes or different colors on the horizon. When the moon or the Sun is low on the horizon, it shines through more atmosphere. If it encounters things like dust particles or pollution, that’s where it can start to change colors. So it’s an optical illusion, and it’s the same one that happens to the Sun sometimes.
When our brains are trying to figure out what color something is, the first thing is how bright it is. Even when the light in a scene doesn’t change, the colors surrounding an object can trick our brains. If brains could make an absolute measurement of light passing through pupils, maybe we wouldn’t be tricked by these color illusions.
The full moon gives enough light that it can even cast shadows on the ground on a night. But it only looks so blindingly bright in the night sky because there’s nothing else nearby it to compare to, except the night sky itself. Instead of measuring the absolute number and wavelength of photons, the moon gives off, our eyes and brains compare the relative amounts of light given off by two or more objects within our field of view.
The moon only reflects about 13% of the light that hits its surface. But in the night sky, against the dark blackness of space, it’s the brightest thing we can see, so our brains tell us “that’s white.”
But if you viewed the moon next to Earth, it would be a very dark gray, almost like an asphalt road under the same illumination. You can see this dark gray color in photos taken on the moon during the Apollo missions. Compared to a white spacesuit, suddenly, the moon doesn’t seem as bright.
Why does the moon shine with different color?
As the orbit changes, the light angle also changes, and less light bounces back to earth. It only reflects 8% of the light to earth during the various quarter stages of the moon. The moon has an elliptical orbit. So occasionally, it gets closer. The moon reflects about 20% of the light, and we call this a super moon.
The light from the super moon is so bright that astronomers cannot use their telescopes. The moon is made up of ancient volcanic rock about 4.5 billion years old and is around about the age of the solar system. So this is pretty old rock.
Since there isn’t any atmosphere on the moon, the surface only changes when another space object hits it. For example, an asteroid has caused the moon to have a lot of craters and mountains. As the moon’s orbit angle changes, the angle of the hills and craters also changes. The light from this that’s reflected becomes dimmer. When there’s a sharper angle from the Sun’s light, it causes the craters and the mountains to cast shadows. It is why the moon is less bright at certain times in its orbiting cycle.
The earth and the moon both have a gravitational pull, and the moon’s gravitational pull causes the ocean tides on the planet. Thousands of years ago, the moon was much closer to the earth. It means the people in the distant past must have seen the moon larger and brighter in the night sky. It is because the amount of light reflected was a lot more than it is today.
- Why Moon Turns Red & Blood Moon
- Why Does The Moon Look So Big & Different Size
- Why Clouds Are White & Explanation
- Why Is The Sky Red At Night, Sunrise & Sunset
Archinal, Brent A.; A’Hearn, Michael F.; Bowell, Edward G.; Conrad, Albert. “Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements.” Celestial Mechanics and Dynamical Astronomy.
Matthews, Grant. “Celestial body irradiance determination from an underfilled satellite radiometer: application to albedo and thermal emission measurements of the Moon using CERES.”
Bugby, D. C.; Farmer. Two‐Phase Thermal Switching System for a Small, Extended Duration Lunar Surface Science Platform. AIP Conference Proceedings.
Vasavada, A. R.; Paige, D. A.; Wood. “Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits.”
Lucey, Paul; Korotev, Randy, Maurice, Sylvestre. “Understanding the lunar surface and space-Moon interactions.” Reviews in Mineralogy and Geochemistry.