On Aug. 21, 2017, people across the United States will see the sun disappear behind the moon, turning daylight into twilight, causing the temperature drop rapidly and revealing massive streamers of light streaking through the sky around the silhouette of the moon. On that day, America will fall under the path of a total solar eclipse .
The so-called Great American Total Solar Eclipse will darken skies all the way from Oregon to South Carolina, along a stretch of land about 70 miles (113 kilometers) wide. People who descend upon this "path of totality" for the big event are in for an unforgettable experience.
WHAT IS A TOTAL SOLAR ECLIPSE? A total solar eclipse occurs when the disk of the moon appears to completely cover the disk of the sun in the sky. The fact that total solar eclipses occur at all is a quirk of cosmic geometry. The moon orbits an average of 239,000 miles (385,000 kilometers) from Earth — just the right distance to see the same size in the sky as the much-larger sun. However, these heavenly bodies line up only about once every 18 months.
Outside the path of totality, skywatchers in the continental U.S. and other nearby areas will see a partial solar eclipse, in which the moon appears to take a bite out of the sun's disk. Two to five solar eclipses occur each year on average, but total solar eclipses happen just once every 18 months or so.
This is a great opportunity to travel. CLICK HERE to see the best park travel destinations for seeing the 2017 total solar eclipse.
Here is Space.com's complete guide to the 2017 total solar eclipse. It includes information about where and when to see it (state by state), how long it lasts, what you can expect to see, and how to plan ahead to ensure you get the most out of this incredible experience.
REMEMBER: Looking directly at the sun, even when it is partially covered by the moon, can cause serious eye damage or blindness. NEVER look at a partial solar eclipse without proper eye protection .
Will there be a live stream? Yes - Nasa will host an Eclipse Megacast for four hours during the eclipse which will be picked up by local, national and international TV stations. You can also follow all the action via the Telegraph.
See SPACE.COM'S complete guide to find out how to view the eclipse safely.