Spring Equinox on Mar 20
“The March equinox is the movement when the sun crosses the true celestial equator – or the line in the sky above the earth’s equator – from south to north, around March 20 (or March 21) of each year. At that time, day and night are balanced to nearly 12 hours each all over the world and the earth’s axis of rotation is perpendicular to the line connecting the centers of the earth and the sun.
The March equinox will occur on March 20 in 2011, marking the beginning of spring in the northern hemisphere and fall (autumn) in the southern hemisphere from an astronomical viewpoint. The March equinox will occur in New York on Mar 20th @ 7:21pm (or 11:21 pm Universal Time) on this date.
This illustration, which shows an example only of the March equinox, is not to scale.
Twice a year, around March 20 or 21 and September 22 or 23, the sun shines directly on the equator and the length of day and night are nearly equal in all parts of the world. These two days are known as the March(vernal or spring in the northern hemisphere) equinox and the September equinox.” (From TimeandDate)
.
Astronomy Spring Break Extra Credit #2 Due Apr 5(T):
-> If you are thinking about doing this assignment – you have to email me by Monday (Mar 21) at noon.
1. Where is the Sun?
Find out how far from zenith and the horizon, the sun is at 12 noon today… the noon solar zenith angle? It’s really simple to figure out. Find out your latitude on the globe… Ok, now use this simple formula to determine the sun angle with respect to your location:
Sun angle = Latitude or solar noon zenith angle – zenith angle on a specific date
Example: Imagine we were are at the Kennedy Space Center, Florida where the latitude is 28.4*N… so, the Solar noon zenith angle is your latitude (28.4 N) – March 21 noon zenith angle (0 degrees). Simply put, the sun at Noon today will be about 28 degrees from directly overhead. So, how far from the horizon does this make the sun at high Noon? Remember from math class there are 90 degrees in a right angle, so subtract the number you just got (28 degrees) from 90 to get 62 degrees from the horizon.
2. Can you balance an egg on end on the equinox? as the urban legend says. Read 3 articles: about the Urban Legend, Egg Spin by Bad Astronomy & Vernal Equinox Views.
- Take a picture of your balanced egg
- Be ready to present your findings to the class on Apr 5th.