rayleigh
Noun. (physics, astronomy) A unit of brightness (of the sky at night) equal to 1010/4π quanta per square meter per second per steradian.This is an unmodified, but possibly outdated, definition from Wiktionary and used here under the Creative Commons license. Wiktionary is a great resource. If you like it too, please donate to Wikimedia.
This entry was last updated on RefTopia from its source on 3/20/2012.