A solar eclipse occurs when the moon passes between the sun and Earth, blocking all or part of the sun.

Eclipses occur because although the sun is 400 times wider than the moon, the star is also 400 times farther away, so to observers, they appear to be the same size in the sky, according to the special eclipse website (eclipse2017.nasa.gov) run by the National Aeronautics and Space Administration (NASA).

The eclipse on Aug. 21 will be visible, depending on weather conditions, across the entire North American continent. An estimated 500 million people will be able to see the eclipse.

A partial eclipse lasting two to three hours will be visible to the whole continent, however, a total eclipse – where the moon completely blocks the sun – will be experienced by portions of 14 states.

This total eclipse will be visible for up to 2 minutes, 43 seconds to anyone within a path that’s approximately 70 miles wide and stretches from Lincoln Beach, Oregon on the West Coast to Charleston, South Carolina on the East Coast, according to NASA’s eclipse website.

NASA says a total of 12.2 million Americans live within the path of the total eclipse.

Unfortunately, none of Michigan is within this path, however, the majority of the sun will be covered here.

In the Detroit area, the partial eclipse will begin at 1:03 p.m. and end at 3:47 p.m. The maximum coverage, when the moon is closest to the center of the sun, will occur at 2:27 p.m. At this time, approximately 80 percent of the star will be obscured.

The last time a total solar eclipse crossed the width of the United States was June 8, 1918, the same year World War I ended.

The last total solar eclipse seen from the contiguous U.S. was on Feb. 26, 1979 and it was visible in the northwestern states and parts of Canada.

The next total eclipse won’t occur until April 8, 2024 and it will be visible from Texas to Maine.

According to the NASA website, experiencing a total solar eclipse where you live happens on average about once in 375 years.