Tuesday, March 16, 2010

12 Hours of Daylight!

The Sun will cross the equator shortly after noon EST on 3/20 this year at a place in the sky we call the equinox, but tomorrow - 3/17 - is the day when we'll have 12 hours of daylight and 12 hours of night...Learn why here.

The image above was made in Stellarium, and shows the location of the Sun as viewed from White Plains, NY at the moment of the 2010 vernal equinox on 3/20.  The blue line is the celestial equator, and the red line is the annual path of the Sun among the stars (it moves to the left, or east, among the stars at about 1 degree/day due to Earth's revolution around the Sun).  The atmosphere has been "turned off" to reveal the background stars and planets.

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