less than 1 minute read


Horizon, apparent line where the sky meets the land or sea. At sea, its distance varies in proportion to the square root of the height of the observer's eyes above sea level. The celestial horizon is the great circle on the celestial sphere at 90° from the zenith (the point immediately above the observer).

Additional topics

21st Century Webster's Family Encyclopedia21st Century Webster's Family Encyclopedia - Hobbema, Meindert to Human Rights, Declaration of