On December 25, 2000, people living in the continental United States, Mexico, Canada, Central America, the Caribbean and the North Atlantic received an extra special Christmas gift. A partial solar eclipse!

20 to 60% of the sun was covered up by the moon's shadow. When the eclipse reached its maximum phase at 17:23 GMT, 72% of the sun was obscured from view.

A solar eclipse, either full or partial, can only occur when the moon passes between the Earth and the sun. This is known as the New Moon phase. If the moon's shadow falls on the surface of the Earth during the New Moon, the moon appears to cover or eclipse a part or all of the sun.

Every New Moon doesn't result in a solar eclipse though. The moon's orbit around the Earth has a five-degree tilt compared to the Earth's orbit around the sun, so the moon's shadow usually misses the Earth. However, at least twice a year, the orbits match up just right and part of the moon's shadow will fall on the Earth creating an eclipse.

Past Christmas Eclipses:

December 25, 1666:
A total solar eclipse is visible in South America.

December 25, 1954:
This year an annual eclipse, where the moon's shadow leaves a halo-like ring of light around the sun occurred. This was visible from the southern hemisphere of over Africa.

Future Christmas Eclipses:

December 25, 2307:
The very next partial solar eclipse will be visible off the western coast of Africa.

December 25, 2755:
After the 2307 solar eclipse, this will be the next one. This eclipse will be visible over Europe.

Mythology of the Solar Eclipse

The world eclipse is Greek for "abandonment." The Greeks believed that the sun was abandoning the earth during an eclipse.

The most common belief about a solar eclipse involves a dragon or a demon devouring the sun. During an eclipse, the ancient Chinese would make extremely loud noises by banging on drums or pots to scare the dragon away. The Incas would also try to scare away the creatures eating the sun.

In ancient India, people would sink themselves in water up to their necks. This was considered an act of worship believed to help the sun fight off the dragon.

Hopefully this year, nothing gets eaten but traditional Christmas fare.

UselessKnowledge About Solar Eclipses

• The longest duration for a total solar eclipse is 7.5 minutes.

• A total solar eclipse is not noticable until the Sun is more than 90 percent covered by the Moon. At 99 percent coverage, daytime lighting resembles local twilight.

• Eclipse shadows travel at 1,100 miles per hour at the equator and up to 5,000 miles per hour near the poles.

• The width of the path of totality is at most 167 miles wide.

• The maximum number of solar eclipses (partial, annular, or total) is 5 per year.

• There are at least 2 solar eclipses per year somewhere on the Earth.

• Only partial solar eclipses can be observed from the North and South Poles.

• Total solar eclipses happen about once every 1.5 years.

• Nearly identical eclipses (total, annual, or partial) occur after 18 years and 11 days, or every 6,585.32 days (Saros Cycle).

• The Saros Cycle exists because it takes 18 years and 10 days for the entire orbit of the Moon to precess once around in its orbit plane so that the lunar nodes make one complete revolution along the orbit. This "Nordical" period equals nearly an integer number of lunar months (223 x 29.53 days = 6,585.19 days) during each Saros Cycle. Because the true length of the Saros Cycle is 6,585.32 days, you have to wait THREE Saros Cycles in order for an eclipse to repeat at the same spot on Earth.

• Successive eclipses in the Saros Cycle happen 1/3 of the way around the world from each other, and after three Saros Cycles, the eclipse returns to nearly the same geographic location after 54 years and 33 days.

• Twelve different Grand Saros eclipse series are now occurring, with the one producing the eclipses of 1937, 1955, 1973, 1991, and 2009 having durations near the 7.5 minute limit.

• Every eclipse begins at sunrise at some point in its track and ends at sunset about half way around the world from the start point.

• Partial solar eclipses can be seen up to 3,000 miles from the track of totality.

• Before the advent of modern atomic clocks, studies of ancient records of solar eclipses allowed astronomers to detect a 0.001 second per century slowing down in Earth's rotation.

• Total solar eclipses happen because the Sun is near one of the nodes of the lunar orbit, and the Moon is at perigee at this node at the same time.

• Annular solar eclipses happen because the Sun is near one of the nodes of the lunar orbit, and the Moon is at apogee at this node at the same time.

• Shadow bands are often seen on the ground as totality approaches.

• Light filtering through leaves on trees casts crescent shadows as totality approaches.

• Local animals and birds often prepare for sleep or behave confusedly during totality.

• Local temperatures often drop 20 degrees or more near totality.

• During totality, the horizon is illuminated in a narrow band of light, because an observer is seeing distant localities not under the direct umbra of the Moon's shadow.