An April 8, 2024, solar eclipse will give tens of millions of skywatchers a chance to experience the celestial phenomenon – the last chance to do so from the U.S. until 2045, scientists say.
With two years to go, here's what to know about the 2024 total solar eclipse.
When Is the Next American Solar Eclipse?
The next total solar eclipse visible from the U.S. and North America will occur on April 8, 2024, beginning around 10 a.m. in Mexico and ending in the late afternoon over Maine and eastern Canada.
The last total solar eclipse in the U.S. occurred Aug. 21, 2017, and it was seen by millions as it crossed the country from Oregon to South Carolina. Prior to that, the last total solar eclipse visible in the U.S. was in 1979.
2024 Eclipse Path
The 2024 total eclipse of the sun is expected to start in Mexico, make its way through the U.S. from Texas to Maine and on through the eastern tip of Canada. Those directly along the path of totality will have the best views, but everyone in the continental U.S. will see at least a partial solar eclipse.
The path crosses through 15 U.S. states, according to Astronomy.com: Texas, Oklahoma, Arkansas, Missouri, Tennessee, Kentucky, Illinois, Indiana, Ohio, Michigan, Pennsylvania, New York, Vermont, New Hampshire and Maine.
What Is a Solar Eclipse?
A total solar eclipse occurs when the sun, the moon and Earth are aligned. The moon, directly between the sun and Earth, casts a shadow on the planet, darkening the daytime sky. Those in the dark part of the moon’s shadow (the umbra) will experience a total eclipse, while those in the light part (the penumbra) will see a partial eclipse.
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What Is the Period of Totality?
The period of totality refers to the time during a total eclipse when the moon completely obscures the sun. The period of totality is usually brief, lasting just a few minutes. Astronomy.com says the maximum period of totality for the April 8, 2024, solar eclipse is four minutes and 28 seconds.
The longest period of totality for the 2017 solar eclipse was quite a bit shorter, just about two minutes and 40 seconds, according to NASA.
How to Safely Watch a Total Solar Eclipse
It is never safe to look directly into the sun, even if it's partially obscured. Anyone watching a partial eclipse must wear eclipse glasses at all times if facing the sun, or use an alternate indirect method, NASA says. This also applies during a total eclipse up until the period of totality, when the sun is totally blocked. During that short time, when the moon completely obscures the sun, it is safe to look directly at the star, NASA says, but timing is crucial. Learn more about eye safety during solar eclipses on NASA's website.