On Monday, August 21 the sun, moon and Earth will line up in an act of cosmic serendipity that will turn day into night across the 2,680-mile width of the United States.
It will be the first time that has happened in nearly a century, and never will a total solar eclipse be so heavily viewed and studied.
From Oregon in the west, to South Carolina in the east, there will be festivals and flamboyant eclipse viewing parties. And of course, traffic gridlock, an social media explosion, and general chaos
As one astronomer put it: “This will be the most photographed, most shared, most tweeted event in human history.”
How unusual an event is this?
Full solar eclipses, when the moon positions itself smack between the sun and the Earth, happen every few years but often in remote areas or over the ocean.
This will be the first total solar eclipse in 99 years to cross the US coast-to-coast, and the first to pass through any part of the lower 48 states in 38 years.