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Earth's celestial sphere: Stars, planets, and other heavenly bodies
Learn what makes the sky look blue
Understand the phenomenon of the yellow color sun and the blue sky
Discover why the sky is dark at night and why space appears dark
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Lightning over the outskirts of Oradea, Rom., during the thunderstorm of August 17, 2005.
16 Questions About Earth’s Atmsophere and Weather Answered
Discover
Rural Irish landscape, Sligo, Ireland.
Why Is Ireland Two Countries?
The Cheshire Cat is a fictional cat from Lewis Carroll's Alice's Adventures in Wonderland. (Alice in Wonderland)
11 Banned Books Through Time
Woman tied to a ducking stool, a method of punishment by means of humiliation, beating, or death. (cucking stool)
8 Unusual Punishments Inflicted on Women Throughout History
Thanksgiving Turkey with all the sides
Why Do We Eat Turkey on Thanksgiving?
A human Inuit skull in a stone chambered cairn in Ilulissat in Greenland. These ancient graves are pre christian and are at least 2000
14 Tough Questions Answered
Thumbnail for flags that look alike quiz Russia, Slovenia, Iceland, Norway
Flags That Look Alike
Super Typhoon Noru over the western tropical Pacific Ocean as observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA Aqua satellite July 31 2017
What Is the Difference Between a Typhoon and a Super Typhoon?

sky

atmosphere

Learn about this topic in these articles:

blue colour

  • sunlight
    In sunlight

    …the varying colour of the sky at different times of day. When the sun is high overhead, its rays pass through the intervening atmosphere almost vertically. The light thus encounters less dust and fewer air molecules than it would if the sun were low on the horizon and its rays…

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  • Photosynthesis
    In electromagnetic radiation: Scattering, reflection, and refraction

    …it is the reason the sky is blue and the setting Sun is red. The higher-frequency blue light from the Sun is scattered much more by the atoms and molecules of Earth’s atmosphere than is the lower-frequency red light. Hence, the light of the setting Sun, which passes through a…

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Rayleigh scattering law

  • Lord Rayleigh, engraving by R. Cottot.
    In Lord Rayleigh

    …the blue colour of the sky as the result of scattering of sunlight by small particles in the atmosphere. The Rayleigh scattering law, which evolved from this theory, has since become classic in the study of all kinds of wave propagation.

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