Why is the sky blue
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http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Skyblue.shtml |
Sunlight
is made up of all the colors of the rainbow: red,
orange, yellow,
green, blue,
and violet. The gas molecules in the
atmosphere interact with the sunlight before the light reaches our eyes.
The
gas molecules in the atmosphere scatter the higher-energy (high frequency)
blue portion of the sunlight more than they scatter the lower-energy
red portion of the sunlight (this is called Raleigh scattering,
named for the physicist Lord John Raleigh). The Sun appears reddish-yellow and
the sky surrounding the Sun is colored by the scattered blue waves.
When
the Sun is lower in the horizon (near sunrise or sunset), the sunlight must
travel through a greater thickness of atmosphere than it does when it is
overhead, and even more light is scattered (not just blue, but also green,
yellow, and orange) before the light reaches your eyes.
This makes the sun look much redder.
Caution: Never stare directly at the Sun. |