March 20, 2015 is the first day of spring for the Northern Hemisphere. Google is celebrating the vernal equinox with a Google Doodle.
Here’s what you need to know:
1. It’s Also Known as the ‘Vernal Equinox’
The first day of spring is also known as the spring equinox, or the vernal equinox. The spring equinox is one of the two annual equinoxes where the sun shines directly on the equator and the length of day and night is nearly the same. “Vernal” means “of relating to spring” in Latin.
The spring equinox lands on either March 20 or 21 every year and is one of the four seasonal astronomical events that impacts earth. The other three are the summer solstice, the autumnal equinox, and the winter solstice.
2. It’s Different Than a Solstice
Equinoxes are different than solstices. Solstices occur in the summer and winter. When the earth rotates on its axis, it reaches the point of maximum tilt, either when the northern hemisphere is the most tilted away from the sun, winter, or when it is tilted toward the sun, summer.
For inhabitants of the Northern Hemisphere, the winter solstice process becomes most noticeable around December 1 when the sun appears to “move” south and get smaller. By the day of the actual winter solstice, the sun has reached its lowest point in the sky at -25.5°. Once it has reached this lowest point, an interesting thing happens: the sun appears to stop moving south for three days. After this, the sun moves 1° north, announcing the coming of spring. It will continue to move northward until the summer solstice, when it reaches its highest point.
3. Lots of Religions Have ‘Rebirth’ Holidays Around This Time
There was a lot of religious mysticism involved with spring equinox in the ancient world that has translated into our modern world with many holidays, all sharing similar themes. The most common theme is rebirth and renewal.
The death and resurrection of a god is also a common motif.
Ancient gods and goddesses included in included in this are Baal, Melqart, Adonis, Tammuz, Dionysus, Ishtar, Persephone, and Bari.
These gods have been replaced by new ones, and now Christians celebrate Easter, Hindus Holi, and Persians Nowruz around this time. All of these celebrations are viewed as a time of transition and new beginnings.
4. It’s the Autumnal Equinox in the Southern Hemisphere
While the Northern Hemisphere prepares for spring, the Southern Hemisphere prepares for fall.
This means that as the Northern Hemisphere progresses into summer, continents like Australia and and South America will begin to transition into winter.
5. It Might Not Feel Like Spring Right Away
While the official first day of spring is related to when the equinox occurs, it might not feel like spring right away—especially for more northern latitude countries like the USA and Canada. That’s because spring weather varies with climate and how far you are away from the equator. But rest assured, warmer weather will come!