National Aeronautics and Space Administration
Goddard Space Flight Center
Sun-Earth Day 2012: Total Solar Eclipse, Australia
- 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 Moon's shadow is at most 170 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.
- A total eclipse can only happen during a new moon.
- Total solar eclipses happen about once every year or two.
- Nearly identical eclipses (total, annual, or partial) occur after 18 years and 11 days, or every 6,585.32 days (Saros Cycle).
- From the Earth's surface, the Sun's corona ("crown") can ONLY be seen during a total eclipse.