Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
sky
Directory
References
Videos
Diagram stars, planets, constellations, and other heavenly bodies by understanding Earth's celestial sphere
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
Read Next
Lightning over the outskirts of Oradea, Rom., during the thunderstorm of August 17, 2005.
16 Questions About Earth’s Atmsophere and Weather Answered
Discover
Black widow spider
9 of the World’s Deadliest Spiders
Solar eclipse of the sun.
The Sun Was Eaten: 6 Ways Cultures Have Explained Eclipses
earthquake. Heavily damaged school in the town of Yingxiu after a major earthquake struck China's Sichuan Province on May 12, 2008.
The 6 Deadliest Earthquakes Since 1950
United States Electoral College votes by state
How Many Electoral College Votes Does Each U.S. State Have?
Periodical Cicada, Adult, Magicicada spp. Requires 17 years to complete development. Nymph splits its skin, and transforms into an adult. Feeds on sap of tree roots. Northern Illinois Brood. This brood is the largest emergence of cicadas anywhere
Why Do Some Cicadas Appear Only Every 17 Years?
Pluto. The Changing Faces of Pluto. Most detailed view to date of the entire surface of the dwarf planet Pluto, as constructed from multiple NASA Hubble Space Telescope photographs taken from 2002 to 2003.
10 Important Dates in Pluto History
Albert Einstein in Washington, D.C. c. 1921-1923. Physicist
The Solar Eclipse That Made Albert Einstein a Science Celebrity

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…

    Read More
  • 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…

    Read More

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.

    Read More