SolsticeSolstice

DEFINITION: an astronomical event that DEFINITION: an astronomical event that happens twice each year as the Sun reaches its happens twice each year as the Sun reaches its highest or lowest point in the skyhighest or lowest point in the sky

LATIN: sol (sun) and sistere (to stand still). LATIN: sol (sun) and sistere (to stand still).

The Sun appears to stand still in as the Sun's The Sun appears to stand still in as the Sun's path (as seen from Earth) comes to a stop path (as seen from Earth) comes to a stop before reversing direction.before reversing direction.

SolsticesSolsticesSolsticesSolstices• SolsticesSolstices occur twice a year, when the tilt of the Earth's occur twice a year, when the tilt of the Earth's

axis is oriented directly towards or away from the Sun, axis is oriented directly towards or away from the Sun, causing the Sun to appear to reach its northernmost and causing the Sun to appear to reach its northernmost and southernmost extremes. southernmost extremes.

• Winter solstice is the shortest day of the year. In the Winter solstice is the shortest day of the year. In the Northern Hemisphere. It occurs on December 21 and Northern Hemisphere. It occurs on December 21 and marks the beginning of winter.marks the beginning of winter.

• The Summer Solstice is the longest day of the year. It The Summer Solstice is the longest day of the year. It occurs on June 21 and marks the beginning of summer. occurs on June 21 and marks the beginning of summer.

• SolsticesSolstices occur twice a year, when the tilt of the Earth's occur twice a year, when the tilt of the Earth's axis is oriented directly towards or away from the Sun, axis is oriented directly towards or away from the Sun, causing the Sun to appear to reach its northernmost and causing the Sun to appear to reach its northernmost and southernmost extremes. southernmost extremes.

• Winter solstice is the shortest day of the year. In the Winter solstice is the shortest day of the year. In the Northern Hemisphere. It occurs on December 21 and Northern Hemisphere. It occurs on December 21 and marks the beginning of winter.marks the beginning of winter.

• The Summer Solstice is the longest day of the year. It The Summer Solstice is the longest day of the year. It occurs on June 21 and marks the beginning of summer. occurs on June 21 and marks the beginning of summer.

Tyrrhenian Sea and Solstice Sky Credit & Copyright: Danilo Pivato

SOLSTICESOLSTICE

• During the winter the Northern During the winter the Northern Hemisphere day lasts fewer Hemisphere day lasts fewer than 12 hours and the than 12 hours and the Southern Hemisphere day Southern Hemisphere day lasts more than 12 hours.lasts more than 12 hours.

• During the winter solstice, the During the winter solstice, the North Pole has a 24-hour night North Pole has a 24-hour night and the South Pole has a 24-and the South Pole has a 24-hour day.hour day.

• Sunlight strikes the earth most Sunlight strikes the earth most directly at the Tropic of directly at the Tropic of Capricorn.Capricorn.

• During the winter the Northern During the winter the Northern Hemisphere day lasts fewer Hemisphere day lasts fewer than 12 hours and the than 12 hours and the Southern Hemisphere day Southern Hemisphere day lasts more than 12 hours.lasts more than 12 hours.

• During the winter solstice, the During the winter solstice, the North Pole has a 24-hour night North Pole has a 24-hour night and the South Pole has a 24-and the South Pole has a 24-hour day.hour day.

• Sunlight strikes the earth most Sunlight strikes the earth most directly at the Tropic of directly at the Tropic of Capricorn.Capricorn.

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EquinoxEquinox

DEFINITION: When the tilt of the Earth's axis DEFINITION: When the tilt of the Earth's axis is inclined neither away from nor towards the is inclined neither away from nor towards the SunSun

LATIN: The name "equinox" is derived from LATIN: The name "equinox" is derived from the Latin aequus (equal) and nox (night).the Latin aequus (equal) and nox (night).

During the equinox, night and day have During the equinox, night and day have approximately equal length.approximately equal length.

EquinoxesEquinoxes

• A day lasts 12 hours and A day lasts 12 hours and a night lasts 12 hours at a night lasts 12 hours at all latitudes.all latitudes.

• Equinox literally means Equinox literally means "equal night"."equal night".

• Sunlight strikes the Sunlight strikes the earth most directly at the earth most directly at the equator. equator.

• This occurs twice a year.This occurs twice a year.

• A day lasts 12 hours and A day lasts 12 hours and a night lasts 12 hours at a night lasts 12 hours at all latitudes.all latitudes.

• Equinox literally means Equinox literally means "equal night"."equal night".

• Sunlight strikes the Sunlight strikes the earth most directly at the earth most directly at the equator. equator.

• This occurs twice a year.This occurs twice a year.

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EquinoxEquinox

• The vernal (spring) The vernal (spring) equinox occurs March equinox occurs March 21.21.

• The autumnal (fall) The autumnal (fall) equinox occurs equinox occurs September 21.September 21.

• The vernal (spring) The vernal (spring) equinox occurs March equinox occurs March 21.21.

• The autumnal (fall) The autumnal (fall) equinox occurs equinox occurs September 21.September 21.