Vernal Equinox 2009 春分

The March Equinox

Vernal Equinox will occur on March 20 in 2009, 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 at 11:44 (am) at Coordinated Universal Time (UTC) on this date.

Picture by Date&Time dot com.

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.

What does equinox mean?
The word “equinox” derives from the Latin words meaning “equal night” and refers to the time when the sun crosses the equator. At such times, day and night are everywhere of nearly equal length everywhere in the world.

It is important to note that while the March equinox marks the beginning of spring in the northern hemisphere, it is the start of autumn in many parts of the southern hemisphere.

March Equinox Explained
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.

In gyroscopic motion, the earth’s rotational axis migrates in a slow circle based as a consequence of the moon’s pull on a nonspherical earth. This nearly uniform motion causes the position of the equinoxes to move backwards along the ecliptic in a period of about 25,725 years.