Spring is officially here, whether the weather agrees or not. Here are some facts about the vernal equinox.
What is the Vernal Equinox?
It’s the day in March when the sun is directly over the equator, equidistant from the poles. To wit, equinox comes from the Latin words “aequus" (equal) and "nox" (night). And it marks the first day of spring. This is, however, only in the Northern Hemisphere. Down south of the equator, it's the autumnal equinox, marking the beginning of their fall season.
When is it?
Good question. It’s always in March, usually on the 20th, but can occur on the 19th or 21st because our rotation around the earth isn’t exactly 365 days. If the time of the equinox happens early enough in Greenwich Mean Time, the equinox can occur at night on the 19th in America but evening on the 20th over in East Asia because the magic of time zones.
No seriously, when exactly does it happen?
The specific time of the equinox changes every year because it’s the exact moment the center of the sun hits the line of the equator. With a solar year that’s just over 365 days, this means the exact time changes every year.
What about this year?
In 2017, the vernal equinox falls on Monday, March 20th at 6:29 a.m. EDT.
When's the Autumnal Equinox?
Same deal, only in September, either the 22nd, 23rd or 24th. And it ushers in Fall. This year it will be on September 22 at 4:02 p.m. Remember: in the Southern Hemisphere, this is the date of their vernal equinox. Spring in Australia, for instance, will begin on this date.
Does it have anything to do with the solstice?
The equinoxes are astronomical events just like the solstices, but the solstice is when the earth is at maximum tilt (at the N. or S. Pole) toward the sun. Those days are the longest/shortest of the year depending on where you live.
What else does the equinox do?
Certain holidays are determined by the vernal equinox, most famously in the West: Easter and Passover. Passover is the first full moon after the equinox, while Easter is determined as the Sunday after the first full moon after the Equinox. There are a lot of calendar clashes that mean the two holidays don’t always happen concurrently like we’re used to.
So shouldn’t it be warm now?
Depends on where you live. The closer you are to the equator, the warmer it is year round. But now the sun is headed our way in the Northern Hemisphere, so warmer days are ahead. Patience is key.
Are day and night equal?
Equinox means “equal night,” but hmm, no. On the equinox, the day is still several minutes longer than the night. Daylight can start before the sun rises, due to twilight and refracted light, meaning there are more light hours than night hours on the equinox. Some call the day there is true equality to day-night hours the equilux — it usually happens a few days before the vernal equinox.
Can I balance an egg on this day?
A common equinox myth is that you can perfectly balance a hardboiled egg on its round side at the exact time of the equinox. Technically, yes — but you can actually do it any time of year, depending on the egg and patience. It's got nothing to do with the equinox or earth’s gravitational alignment.
Source : http://www.nydailynews.com/life-style/spring-vernal-equinox-article-1.3001469