The vernal equinox, marking the 1st day of Spring, arrived at Penn National earlier this March 20th at 1:14 AM. It's the earliest start to spring since 1896! One of the reasons for the early start to the season has to do with the leap year. If it wasn't a leap year, spring would start on March 21st. The equinox occurs at the point when the sun crosses the celestial equator from South to North. Here's a way to visualize this:
At the equinox, the geometric center of the Sun crosses the equator and this point is above the horizon for 12 hours everywhere on Earth. Now when we think about the equinox, we often think about equal hours of daylight and darkness. The word equinox comes from the Latin word "aequus" meaning "equal" and "nox" meaning "night". Although it's close, there are actually a few more minutes of daylight on the equinox than darkness. Last Friday we had 12 hours of daylight and 12 hours of darkness. Sunrise on March 16, 2012 was 7:17 AM and sunset was at 7:17 PM. So you may be asking, why wasn't last Friday the equinox?.jpg)
Well, it all comes down to that exact point when the center of the sun crosses the equator. Sunrise and sunset occur when the top of the sun, not the center, is on the horizon. That's why there are actually a few more minutes of daylight on the equinox. Also, the earth's atmosphere refracts, or bends, light from the sun. So, the top of the sun appears to be above the horizon when it is actually below the horizon.
Enjoy this great, warm Spring living and playing at Penn National!
