CELEBRATE VERNAL EQUINOX DAY! Today, March 20th, at 16:57 UTC (12:57 pm EDT) the center of the sun w
CELEBRATE VERNAL EQUINOX DAY! Today, March 20th, at 16:57 UTC (12:57 pm EDT) the center of the sun will cross directly over the equator, heading from south to north. This event is known as the March or vernal equinox. An equinox happens twice a year, usually on or around March 20 (vernal) and September 22 (autumnal). During an equinox, the earth’s axis is perpendicular to the sun, and both northern and southern hemispheres receive the sun’s rays equally. The name “equinox” comes from the Latin aequus (equal) and nox (night), since night and day are roughly the same length. In reality, the day is still slightly longer than the night, since sunrise and sunset are defined by the edges of the sun’s disk hitting the horizon, rather than the center point. There are many rituals and traditions related to the equinox. For people in the northern hemisphere, it is considered the beginning of spring (autumn in the southern hemisphere), as the center of the sun creeps northward each subsequent day until the northern (summer) Solstice on June 21. Why does the date and time of the equinox vary slightly? The calendar year is exactly 365 days (366 in a leap year), but the tropical, or solar year is 365.242 days long. -Amy References:http://earthsky.org/astronomy-essentials/everything-you-need-to-know-vernal-or-spring-equinoxhttp://aa.usno.navy.mil/faq/docs/equinoxes.php Image credit: Przemyslaw Idzkiewiczhttp://commons.wikimedia.org/wiki/File:Earth-lighting-equinox_EN.png -- source link
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