Next Monday (8), North America will experience its second total solar eclipse in seven years. The Moon will skim the surface of our Sun, casting a shadow over an expanse of Earth below. Along this path, in some parts of the world it will be as dark as night — which is not the case in Brazil.
Skywatchers in Mexico will be the first to see the eclipse on the mainland. From there, the show will head north, reaching the United States through Texas, and then heading northeast until it reaches the coast of Canada.
Why eclipses happen is simple: the Moon sits between us and the Sun. But they’re also complicated. So if you’ve forgotten all your facts, we’re here to break it down for you.
But before we begin, there’s one vital thing to know: It’s never safe to look directly at the Sun during an eclipse (except for the few moments when the Moon has completely obscured its surface).
What is a total solar eclipse?
A solar eclipse occurs when the Moon positions itself between the Earth and the Sun, obscuring the solar surface from our view.
In cosmic terms, it is unusual for this to happen: the Moon is about 400 times smaller than the Sun, but it is about 400 times closer to us. This means that when these two celestial bodies are aligned, they appear to be the same size in the sky.
What other types of eclipses exist?
Annular solar eclipses occur when the Moon is farthest from Earth and appears too small to completely cover the Sun’s surface. Instead, the outer part of the solar disk remains uncovered — a “ring of fire” in the sky.
Partial solar eclipses happen when the Earth, Moon and Sun are imperfectly aligned. The Moon only obscures part of the Sun. There will be two of these in 2025.
The Earth can also position itself between the Moon and the Sun, creating a lunar eclipse. This can be observed once or twice a year.
How dark will it be during the eclipse?
Anywhere along the eclipse’s path, the event will last about two hours or more.
The event will begin with a partial solar eclipse, as the Moon takes a small bite out of the Sun’s edge, and then consumes more and more of its surface. According to NASA, this could last 70 to 80 minutes.
The phase of the eclipse in which the Moon completely blocks the surface of the Sun is called totality. This is the only time the event can be seen with the naked eye.
The length of the entirety varies depending on location. Some places will experience this phase for more than four minutes; others, for just a minute or two.
During totality, the sky will be dark as night, and the temperature will drop. Delicate white strands of light from the Sun’s outer atmosphere, or corona, will suddenly be visible. Lucky viewers may even spot a thin reddish circle around the edge of the Moon. This is the chromosphere, an atmospheric layer beneath the Sun’s corona. Its color comes from the presence of hydrogen throughout the layer.
After totality, the Sun will slowly appear behind the Moon again — another partial eclipse that will last as long as the first. The Moon will move away until the Sun returns to its normal brightness.
How can I watch the solar eclipse safely?
In general, avoid looking directly at the Sun without special equipment to protect your eyes. Inexpensive options for watching the eclipse include paper solar viewers and glasses.
According to NASA, it is not safe to look at the Sun through any optical device when using glasses or paper visors. To watch the eclipse through cameras, binoculars or telescopes, purchase a special solar filter.
The only time you can see a solar eclipse with the naked eye is during moments of totality. As soon as the Moon begins to reveal the Sun’s surface again, return to viewing the event using protective gear to avoid injury.
Where are the best places to watch the eclipse?
The total eclipse will sweep across large parts of Mexico, the United States and eastern Canada.
How long will the eclipse last?
The duration of totality depends on how far a given location on Earth is from the Moon. Places with longest totality are closest to the Moon and furthest from the Sun. The speed of the lunar shadow is slowest over locations with longest totality .
The longest period of totality will occur over Durango, a state in Mexico, for a total of 4 minutes and 29 seconds. Along the centerline, the location of the shortest totality on land is off the east coast of Newfoundland and Labrador, Canada, for about 2 minutes and 54 seconds. But totality is even shorter along the edges of the total eclipse path; in some places it lasts less than 1 minute.
How fast does the eclipse move?
Solar eclipses may appear to happen slowly, but the Moon’s shadow is running across the Earth’s surface. Exact speeds vary by location. Eclipse calculators estimate that the shadow will move at about 2,500 km per hour across Mexico and more than 4,800 km per hour until it leaves the United States. The eclipse will reach speeds of over 9,600 km per hour over the Atlantic Ocean.
Do other planets have solar eclipses?
Yes, any planet in our Solar System with a Moon can experience a solar eclipse.
The moons on other planets, however, appear to be smaller or larger than the Sun in the sky. Only Earth has a Moon of the right size and at the right distance to produce the unique effects of totality.
When will the next total solar eclipse be?
If you’re willing to travel, the next total solar eclipse will be on August 12, 2026. People in parts of Greenland, Iceland, Portugal and Spain will be able to witness the event.
