Here's an indepth breakdown of Spring by my friend Steve Russo from the East KY Science Center
So you go to bed tonight and it is Winter, and you wake up tomorrow morning and it is Spring. So how and why does this all happen?
Each year around March 20th or so, we say hello to Spring, or what us Astronomy folks call the Vernal Equinox. But each year, this happens at a slightly different time. Here is a “simple” explanation on how this happens.
We need to go back thousands of years ago when the ancients kept track of the sky better than we did. In order for them to track the Sun, Moon, planets, and other celestial objects, they filled the sky with a grid work of all sorts of lines. Those lines were later brought down to the Earth to be used as Longitude and Latitude.
Two lines were very important. One was the Celestial Equator, the Earth’s equator extended into space, and the other was the Ecliptic, the apparent path of the Sun in the Sky. The Moon and planets can lie on this imaginary line or close to it. The Celestial Equator and Ecliptic are not parallel in the sky but offset by 23.5 degrees. Kind of like two Hoola Hoops (I just dated myself) that are offset and intersect each other in two places.
As the ancients observed the sky, as the Sun moved around on the Ecliptic, at some point it would hit the spot where it intersected with the Celestial Equator. Spring, or Fall would begin, depending on the time of the year. In the case of Spring, that would be someplace in between March 19th and 23rd. The date varies each year due to the fact that the revolution speed of the Earth around the Sun is not steady and changes. Other things factor into this but too complicated to explain in a simple way at this point in time. This year, the Vernal Equinox begins On March 20th at 7:02 AM.
Here in the Prestonsburg area, the Sun will rise exactly east and will set exactly west. There are only two days of the year that happens; the first day of Spring and the first day of Fall. It will rise at 7:35, and will set at 7:42 giving us a “day” of 12 hours and 7 minutes. Now we very often hear that on the Equinox (a word that loosely translates into equal day and equal night) that there are 12 hours of day and night. In reality, that hardly ever happens. Actually, that equality was on Sunday when the Sun was up for 12 hours.
The other idea about the Sun, is that it is overhead at noon. Well tomorrow at noon (actually 1:38 PM because of Daylight Saving Time), the Sun is at its highest point of 52.5 degrees above the south horizon. Now it will be higher on the first day of Summer, but only about 77 degrees above the south horizon.
And the last thing about the Equinox is all about what we sometimes see on TV, or hear about; the fact that only on the Equinoxes, can you balance an egg on its end due to some mystical gravitational force. Sorry folks! While it may sound cool, there are no special gravitational forces on the Equinox, and an egg can be balanced on its end on any day of the year if you have a steady hand, a level surface, and lots of patience.
Enjoy Spring, and,
“Look to the Skies!!!!”Steve