The countdown is on for Aug. 21, when a total solar eclipse will be visible across the United States for the first time in decades. Here's everything you need to know about the event that you don't want to miss.
What is it?
A total solar eclipse is when the moon moves between the sun and Earth, lasting for up to about three hours from beginning to end. The shadow will darken the sky, temperatures will drop and bright stars will appear at a time that is normally broad daylight.
Retired NASA astrophysicist and photographer Fred Espenak said the experience usually lasts for just a couple minutes, but it's truly out of this world.
Espenak said a total solar eclipse can last as long as seven minutes. For the Aug. 21 eclipse, NASA anticipates the longest period when the moon obscures the sun's entire surface from any given location along its path to last about two minutes and 40 seconds.
Who can see it?
NASA estimates more than 300 million people in the United States potentially could directly view the total solar eclipse on Aug. 21. The relatively thin path of totality will sweep across portions of 14 U.S. states: Oregon, Idaho, Wyoming, Montana, Nebraska, Iowa, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina.
However, a partial solar eclipse will be visible in every U.S. state on Aug. 21. In fact, everyone in North America, as well as parts of South America, Africa and Europe, will see at least a partial eclipse, according to NASA.
Here's a video of timeline for Monday August 21st: VIDEO