A total solar eclipse is a singularly magnificent phenomenon. The Great American Eclipse on August 21, 2017, will be visible as either a partial or a total eclipse throughout North America. See how it appears from various vantage points on Earth, and watch from space as the shadow sweeps across the continent.
[From a position in space, we see the night side of Earth and the distant Moon and Sun aligned with one another.]
Planets and moons cast long, cone-shaped shadows that extend away from the Sun.
Every month the Moon passes between Earth and the Sun.
Typically, the Moon orbits above or below the direct line between them, and its shadow misses Earth.
[We pull away from Earth and pan around to the day side, close to the Moon's orbit. The Moon enters our view, now lit by the sun.]
Occasionally the Moon crosses this line, and casts its shadow across Earth's surface.
On August 21, 2017, the Moon will pass directly between Earth and the Sun.
Most of North America will experience a partial eclipse, when the Moon covers only a portion of the Sun.
[We fly past the Moon towards Earth, and start to see a dark spot in the Pacific Ocean, off the coast of Oregon.]
But those along a narrow band will experience a total eclipse, when the Moon fully blocks the Sun.
The shadow will cross the continent, passing through 12 U.S. states in about an hour and a half.
[The Moon's shadow continues across the US. As it passes over each state, a city is marked with a red dot that quickly fades, and the time for the total eclipse in that city is given in a scrolling list: Salem, OR; Idaho Falls, ID; Thermopolis, WY; Grand Island, NE; Troy KS; Jefferson City, MO; Vienna, IL; Princeton, KY; Nashville, TN; Murphy, NC, Clayton, GA; Columbia, SC.]
[Dissolve to view of the sky from the Earth in Columbia, SC, beginning 1:13 pm EDT, as the Moon begins to cover the Sun. As the Sun and Moon drift right and downward across the view, Moon moves leftward and down, relative to Sun. An image of the start of the partial eclipse lingers.]
The entire eclipse occurs over a few hours, but the total eclipse lasts less than three minutes.
During totality, all direct sunlight is blocked, transforming day into night, revealing the Sun's corona, bright stars, and planets.
[During the brief total eclipse, the blue sky darkens to black, some stars appear in the sky, and the Sun's corona is visible. As sky returns to blue, a transparent image of total eclipse remains.]
The only time it's safe to look directly towards the Sun without a solar filter is during totality.
[Partial eclipse ends.]
[The scene changes to the beginning of the partial eclipse as seen from New York City. The Sun and Moon drift right and down across the view, the Moon moves leftward and down relative to the Sun, covering a growing then shrinking portion of the Sun.] From New York City, the Moon will cover 72% of the Sun at maximum. While it's not safe to view directly with your eye, simple viewers can be made from household materials. [View of 5 phases of eclipse in background.]
For safe viewing tips and instructions to build an eclipse viewer, visit: eclipse2017.nasa.gov
[Fade to black, credits begin to roll. Music fades.]