Editing Solstice (section)

==Relationship to seasons==
{{main|Season}}
The seasons occur because the Earth's axis of rotation is not perpendicular to its orbital plane (the [[plane of the ecliptic]]) but currently makes an angle of about 23.44° (called the [[obliquity of the ecliptic]]), and because the axis keeps its orientation with respect to an [[inertial frame of reference]]. As a consequence, for half the year the Northern Hemisphere is inclined toward the Sun while for the other half year the Southern Hemisphere has this distinction. The two moments when the inclination of Earth's rotational axis has maximum effect are the solstices.

At the [[June solstice]] the [[subsolar point]] is further north than any other time: at latitude 23.44° north, known as the [[Tropic of Cancer]]. Similarly at the [[December solstice]] the subsolar point is further south than any other time: at latitude 23.44° south, known as the [[Tropic of Capricorn]]. The subsolar point will cross every latitude between these two extremes exactly twice per year.
{{subsolar_point_date_graph.svg|400px}}
Also during the June solstice, places on the [[Arctic Circle]] (latitude 66.56° north) will see the Sun just on the horizon during midnight, and all places north of it will see the Sun above horizon for 24 hours. That is the [[midnight sun]] or [[midsummer]]-night sun or polar day. On the other hand, places on the [[Antarctic Circle]] (latitude 66.56° south) will see the Sun just on the horizon during midday, and all places south of it will not see the Sun above horizon at any time of the day. That is the [[polar night]]. During the December Solstice, the effects on both hemispheres are just the opposite. This sees polar [[sea ice]] re-grow annually due to lack of sunlight on the air above and surrounding sea. The warmest and coldest periods of the year in temperate regions are offset by about one month from the solstices, delayed by the earth's thermal inertia.

<gallery class="center">
Image:Seasonearth.png|Orientation of the [[Terminator_(solar)|terminator]] (division between night and day) depends on the season. 
File:Earth-lighting-summer-solstice EN.png|Illumination of Earth by Sun on 21 June. The orientation of the terminator shown with respect to the Earth's orbital plane.
File:Earth-lighting-winter-solstice EN.png|Illumination of Earth by Sun on 21 December. The orientation of the terminator shown with respect to the Earth's orbital plane.
File:north season.jpg|Diagram of the Earth's seasons as seen from the north. Far right: [[southern solstice]]
File:south season.jpg|Diagram of the Earth's seasons as seen from the south. Far left: [[northern solstice]]
File:ReflectedSolarRadiation Solstices.jpg|The globe on an [[equirectangular projection]] to show the amount of reflected sunlight at southern and northern summer solstices, respectively (watts / m<sup>2</sup>).
</gallery>