Learn About Solar Eclipse Science From Today’s Google Doodle

Two cartoon aliens bounce the moon across the sun with their spaceships and offer lessons on solar eclipse science in Monday’s Google Doodle, which marks the “Great American Eclipse” that is set to cross the country.

A solar eclipse occurs when the moon passes between the sun and Earth, briefly blocking the sun’s light. Monday’s total solar eclipse, will begin at Lincoln Beach, Ore. at 10:16 a.m. PT, and end less than two hours later near Columbia, S.C.

It will be the first time since 1979 that a total solar eclipse will be visible from the contiguous U.S. and, according to Google, it has been 99 years since a total eclipse crossed the width of the country.

Watch Live as the 2017 Total Solar Eclipse Crosses the U.S.

About 7.4 million people are expected to watch the once-in-a-lifetime event from the path of totality — the 65-mile-wide strip of land where the sun will be entirely obscured. Those not in the path of totality will still be able to witness a partial solar eclipse.

It can be dangerous to watch the eclipse without proper eye protection. Viewers are advised to not look directly at the sun unless they are wearing eclipse glasses.