Equal Night – The Science Behind the First Day of Spring

Hooray it is officially spring!  Walking through the hallways of PS11 today, you could hear teachers, parents, and students celebrating the arrival of the season!  Everyone looked and sounded cheerful…hopeful even.

A few more hours of sunlight and the promise of warmer temperatures can really affect our emotions, but what does the first day of spring mean scientifically…or celestially for that matter.  To learn more about the Spring Equinox check out what NASA and National Geographic have to say.

(The following was taken from NASA.gov)


Earth spins on a tilted axis. As our planet orbits around the sun, that tilt means that during half of the year, the Northern Hemisphere receives more daylight — its summertime — and during the other half of the year, the Southern Hemisphere does.  Twice a year, Earth is in just the right place so that it’s lined up with respect to the sun, and both hemispheres of the planet receive the same amount of daylight. On these days, there are almost equal amounts of day and night, which is where the word equinox — meaning “equal night” in Latin — comes from. The equinox marks the onset of spring with a transition from shorter to longer days for half the planet, along with more direct sunlight as the sun rises higher above the horizon. In 2017, in the Northern Hemisphere, the spring equinox occurs on March 20. Six months later, fall begins with the autumnal equinox on Sept. 22.


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