midnight sun definition of midnight sun in the Free Online Encyclopedia.

midnight sun, phenomenon in which the sun remains visible in the sky continuously for 24 hr or longer, occurring only in the polar regions. The midnight sun is due to the fact that the plane of the earth's equator is tilted about 23 1-2° to the plane of the ecliptic ecliptic (ēklĭp`tĭk, ĭ–)
..... Click the link for more information. (the apparent path of the sun through the sky). Thus, at the summer solstice solstice (sŏl`stĭs) [Lat.
..... Click the link for more information. (about June 22), the sun is still visible on the horizon at midnight at all points along the Arctic Circle Arctic Circle, imaginary circle on the surface of the earth at 66 1-2°N latitude, i.e., 23 1-2° south of the North Pole. It marks the northernmost point at which the sun can be seen at the winter solstice (about Dec.
..... Click the link for more information. , 23 1-2° of latitude from the North Pole. At points north of the Arctic Circle, the midnight sun is visible for longer than one day, the North Pole having a full six months of continuous sun from the vernal equinox equinox (ē`kwĭnŏks), either of two points on the celestial sphere where the ecliptic and the celestial equator intersect.
..... Click the link for more information. (about Mar. 21) to the autumnal equinox (about Sept. 23). In the south polar regions the midnight sun is visible along the Antarctic Circle Antarctic Circle, imaginary circle on the surface of the earth at 66 1-2°S lat., i.e., 23 1-2° north of the South Pole. It marks the southernmost point at which the sun can be seen at the winter solstice (about June 22) and the northernmost point of the
..... Click the link for more information. at the winter solstice (about Dec. 22) and south of the Antarctic Circle for longer periods.