WASHINGTON — The moon will completely blot out the sun for millions of people in North America along a path crossing from Mexico into the US and then Canada in a total solar eclipse occurring on April 8.
Here is an explanation of the solar eclipse and where it will be visible.
In a total solar eclipse, the moon passes between the sun and Earth, entirely covering the face of the sun along a small path of our planet's surface.
This is called the "path of totality." The daytime sky turns dark, akin to dusk or dawn, and nocturnal animals have been known to wake up, confused into believing night has arrived.
In places along the path of totality, people will be able to view the sun's corona — the star's outer atmosphere — that typically is not visible because of solar brightness.
People observing from outside the path of totality will see a partial eclipse in which the moon obscures most of the sun's face but not all of it.
Of course, a cloudy day could spoil the view. After this one, the next total solar eclipse viewable from the contiguous US will not occur until 2044.
According to Nasa, the April 8 eclipse will begin over the South Pacific, with its path reaching Mexico's Pacific coast at around 11.07 am Pacific Time before entering the US in Texas.
Its path then takes it through Oklahoma, Arkansas, Missouri, a tiny piece of Tennessee, Illinois, Kentucky, Indiana, Ohio, a tiny piece of Michigan, Pennsylvania, New York, Vermont, New Hampshire and Maine.
The path then enters Canada in Ontario and journeys through Quebec, New Brunswick, Prince Edward Island and Cape Breton, exiting continental North America on the Atlantic coast of Newfoundland, Canada, at 5.16 pm Newfoundland Time.
A partial eclipse is due to be visible for people in all 48 contiguous US states.
On Oct 14, 2023, people along a path stretching from the US Pacific Northwest, through Mexico, Central America, Colombia and Brazil witnessed an annular solar eclipse, a slightly different event.
An annular solar eclipse occurs when the moon passes between the sun and Earth when the moon is at or near its farthest point from our planet.
Thus, it does not completely cover the face of the sun, leaving what looks like a "ring of fire" in the sky.
Experts warn that it is unsafe to look directly at the bright sun without using specialised eye protection designed for solar viewing.
Viewing an eclipse through a camera lens, binoculars or telescope without making use of a special-purpose solar filter can cause severe eye injury, according to these experts.
They advise using safe solar viewing glasses or a safe handheld solar viewer, noting that regular sunglasses are not safe for viewing the sun.
The only moment it is considered safe for people to remove eye protection during a total solar eclipse is the brief time when the moon completely blocks the sun's surface.
The moon will cover the sun's face, as visible from Earth, only because the moon — in actuality much smaller than the sun — is so much closer to our planet.
The moon's diameter is 2,159 miles (3,476 km), compared to the sun's diameter of about 865,000 miles (1.4 million km) and Earth's diameter of 7,918 miles (12,742 km).
Lunar eclipses occur when Earth is positioned between the moon and the sun and our planet's shadow is cast upon the lunar surface.
This leaves the moon looking dim from Earth, sometimes with a reddish colour. Lunar eclipses are visible from half of Earth, a much wider area than solar eclipses.
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