Equinox and Solstice occur because Earth’s axis of rotation is tilted about 23.4 degrees relative to Earth’s orbit around the sun.
This tilt drives our planet’s seasons, as the Northern and Southern Hemispheres get unequal amounts of sunlight over the course of a year.
From March to September, the Northern Hemisphere is tilted more toward the sun, driving its spring and summer.
From September to March, the Northern Hemisphere is tilted away, so it feels like autumn and winter. The Southern Hemisphere’s seasons are reversed.
What are solstices?
- The word “solstice” originated from Latin word “sol” which means sun and “sistere” which means stationary or stand still.
- On two moments each year—what are called solstices—Earth’s axis is tilted most closely toward the sun.
- The hemisphere tilted most toward our home star sees its longest day, while the hemisphere tilted away from the sun sees its longest night.
- During the Northern Hemisphere’s summer solstice—which always falls around June 21—the Southern Hemisphere gets its winter solstice. Likewise, during the Northern Hemisphere’s winter solstice—which falls around December 22—the Southern Hemisphere gets its summer solstice.
- Solstices can also be thought of in terms of where on Earth the sun appears.
- When it’s a summer solstice in the Northern Hemisphere, the sun appears directly over the Tropic of Cancer, the latitude line at 23.5 degrees North.
- During the Northern Hemisphere’s winter solstice, the sun appears directly over the Tropic of Capricorn, the Tropic of Cancer’s southern mirror image.The word “tropic” comes from Ancient Greek trope, meaning “to turn” or “change direction
During Summer Solstice(June 21)
What is the winter solstice?
21st December or the Winter Solstices marks the shortest day of the year in the Northern Hemisphere.
- It is the shortest day and longest night of the year in the Northern Hemisphere and is also known as the ‘first day of winter’ in the Northern Hemisphere as well as ‘Hiemal solstice or Hibernal solstice’.
- During this, countries in the Northern Hemisphere are farthest from the Sun and the Sun shines overhead on the Tropic of Capricorn (23.5° south).