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Name: Shreyans
Status: student
Grade: 9-12
Country: India
Date: Winter 2011-2012


Question:
We consider sun's light as white as it enters the atmosphere it scatters and give us a color sensation for every object. Though we perceive light reflected from moon as white, why does it not scatter?

Replies:
Shreyans, br>
Light coming from the moon is simply reflected light from the sun, so it will scatter the same as sunlight. Its color may be somewhat different as the moon is not a mirror, but it travels through the same atmosphere on the way to the ground as if it came from the sun. Now, I believe your question may relate to another effect, the perception that moonlight does not cause color. This effect is caused by the fact that moonlight is much less intense than sunlight. We have two types of receptors in our eyes called "rods" and "cones" that perceive light differently. One detects shades of grey (rods) and the other color (cones). Rods are more sensitive and work better in low light than cones. In the low intensity light of the moon, the rods give the world an appearance that it is grey. As light becomes brighter, the cones start perceiving the color around us. You can verify this effect if you have a light that can be adjusted for brightness in a dark room. Take a colorful object and watch it as you turn the light down. The object will become grey. The light does not scatter any differently, but your eye can no longer see scattered light as colorful.

Kyle Bunch


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