Description
A common misconception is that the shortest day is totally dark at each point where the midnight sun occurs inside the polar circle. In places very close to the poles this is true, but in regions that are located at the inner border of the polar circles where the midnight sun is experienced, this is not the case. Because of twilight, these regions experience polar twilight instead of the polar night. In fact, polar regions typically get more twilight throughout the year than equatorial regions.
For regions inside the polar circles, the maximum lengths of the time that the sun is completely below the horizon varies from about 20 hours at the Arctic Circle and Antarctic Circle to 179 days at the Poles. However not all this time is classified as polar night, since sunlight may be visible because of refraction. Also, the time when the sun is above the horizon at the poles is 186 days. The numerical asymmetry occurs because the time when the sun is partially above the horizon is counted towards the "daytime". Also, the above numbers are average numbers: owing to the ellipticity of the Earth's orbit, where the South pole receives a week more of sun-below-horizon than the North pole (see equinox).
Read more about this topic: Polar Night
Famous quotes containing the word description:
“It is possible—indeed possible even according to the old conception of logic—to give in advance a description of all ‘true’ logical propositions. Hence there can never be surprises in logic.”
—Ludwig Wittgenstein (1889–1951)
“Everything to which we concede existence is a posit from the standpoint of a description of the theory-building process, and simultaneously real from the standpoint of the theory that is being built. Nor let us look down on the standpoint of the theory as make-believe; for we can never do better than occupy the standpoint of some theory or other, the best we can muster at the time.”
—Willard Van Orman Quine (b. 1908)
“The next Augustan age will dawn on the other side of the Atlantic. There will, perhaps, be a Thucydides at Boston, a Xenophon at New York, and, in time, a Virgil at Mexico, and a Newton at Peru. At last, some curious traveller from Lima will visit England and give a description of the ruins of St Paul’s, like the editions of Balbec and Palmyra.”
—Horace Walpole (1717–1797)