Conditions for a Total Solar Eclipse and New Moon

Moon's Orbit

• Richard Brill, Professor of Science at Honolulu Community College, points out that the moon travels around the earth at a 5-degree angle relative to the equator. For half of its orbit, it is tilted north to south ,and the other half it is tilted south to north. When it crosses the middle point of its plane, and there is a full or a new moon, then conditions are ripe for an eclipse.

Moon's Shadow

• Fred Espenek, writing for Mreclipse.com, explains there are two parts to the Moon's shadow: the penumbra, or outer shadow, and the umbra or inner shadow. For a total solar eclipse to occur, the Moon's dark inner shadow must strike the Earth during the New Moon phase. This happens about twice a year.

The Path of Totality

• According to Fred Espenak, writing for Mreclipse.com, when the Moon's orbit and shadow is in alignment and it's a New Moon phase, a total solar eclipse can occur; however, not everyone in the world can see it. The track of the Moon's shadow across Earth is known as the path of totality. It is 10,000 miles long and 100 miles wide, which is equal to only one percent of the Earth's surface. To see a total solar eclipse, you must be somewhere inside the narrow path.

Predicting Total Solar Eclipses

• Fred Espanek includes a table on Mreclipse.com depicting all the upcoming solar eclipses until the year 2020. By monitoring the conditions through which total solar eclipses can happen, astronomers are able to predict when solar eclipses will occur. According to the table, there will only be six total solar eclipses on Earth through 2020.