Where does Moonlight come from??

The light coming from the Moon is an illusion. As you know, you’re actually seeing the reflected light from the Sun, bouncing off the Moon which acts like a mirror. A really terrible mirror. When astronauts walked on the surface, they reported that it was dark grey, the color of pavement. Because of its dark color and bumpy surface, it only reflects about 12% of the light that hits it.

The amount of light we get from the Moon depends on the point of its orbit. During its first and last quarters, the Moon is half illuminated, but it’s only 8% as bright when it’s full. Just imagine the surface when its only partly illuminated. With the Sun at a steep angle, the mountains cast long shadows. This makes the lunar surface much darker than when it’s directly illuminated.

During the full Moon, it’s so bright that it obscures fainter objects in the night sky. Many astronomers put their telescopes away during this phase, and wait for it to go away. When the Moon is highly illuminated, it reflects so much light we can even see it during the day.

The brightness of the daytime sky completely washes out the light from the stars, but the Moon is even brighter, and so we can can see it in the sky during the day. The Moon follows an elliptical orbit around the Earth, changing its distance and brightness quite a bit. When it is at its closest point, and it’s full, this is known as a supermoon.

This Moon can be 20% brighter than normal. You’ve probably experienced how the Moon can cast shadows. In fact, there are three objects in the sky that can cast shadows. The Sun, of course, the Moon... and Venus. Venus is the next brightest object in the sky, after the Moon. It reflects 65% of the sunlight that hits it. Every few months, Venus reaches its brightest time - that’s when you can see your shadow. On a night with no Moon, head far away from city lights.

The moon shines because its surface reflects light from the sun. And despite the fact that it sometimes seems to shine very brightly, the moon reflects only between 3 and 12 percent of the sunlight that hits it. The perceived brightness of the moon from Earth depends on where the moon is in its orbit around the planet. The moon travels once around Earth every 29.5 days, and during its journey, it's lit from varying angles by the sun. 

The intensity of moonlight varies greatly depending on the lunar cycle but even the full Moon typically provides only about 0.1 lux illumination. When the Moon is viewed at high altitude at tropical latitudes, the illuminance can reach 0.26 lux. The full Moon is about 1,000,000 times fainter than the Sun.

The Moon's albedo is 0.136, meaning only 13.6% of sunlight incident on the Moon is reflected. Moonlight generally hampers astronomical viewing, so astronomers usually avoid making observations near full Moon. It takes approximately 1.26 seconds for the moonlight to hit the Earths surface.

Posted by: Lusubilo A. Mwaijengo