A solar eclipse happens at the new moon, when the Moon moves between Earth and the Sun. You may have heard that an eclipse happens every month. In fact, it does not. Here is why. The Moon's orbit around Earth is tilted by about five degrees. Most months the new moon passes above or below the Sun, so its shadow misses Earth and there is no solar eclipse. An eclipse season lasts about 35 days and comes again just short of six months later.

The Moon's shadow has a dark center called the umbra and a lighter outer part called the penumbra. To see a total solar eclipse you must be inside the Moon's darkest shadow, the umbra. People standing in the Moon's penumbra see a partial solar eclipse. In a partial solar eclipse, the Moon covers only part of the Sun. The path of totality of the August 12, 2026 total solar eclipse crossed Greenland, Iceland, the Atlantic Ocean and northern Spain, with a small part of Portugal.

In a total solar eclipse, the Moon passes between the Sun and Earth and blocks the face of the Sun. During a total solar eclipse, the daytime sky gets dark, as if it were dawn or dusk. The Sun is about 400 times wider than the Moon but also about 400 times farther away, so they look about the same size in the sky. On Earth, the narrow line where a total solar eclipse can be seen is called the path of totality. A solar eclipse can be seen from only a small part of Earth at a time.

There are four types of solar eclipse: total, partial, hybrid and annular. In an annular solar eclipse the Moon is too far from Earth to cover the whole Sun, so it looks smaller than the Sun. A hybrid solar eclipse is a rare kind that shifts between annular and total along its path; fewer than 5% of solar eclipses are hybrid. In most places, a total, annular or hybrid eclipse looks like a partial eclipse. Eclipses are very useful to scientists, as well as beautiful. The corona is the Sun's outer atmosphere. We cannot normally see it because the Sun's bright surface is in the way, but it shows in a total eclipse.

Now turn to the Moon, which has eclipses too. In a lunar eclipse, Earth's shadow falls on the Moon. A lunar eclipse happens at the full moon, while a solar eclipse happens at the new moon. You may have heard that the Moon goes completely dark in a lunar eclipse. In fact, the Moon in a total lunar eclipse often looks a dull red or orange. In a lunar eclipse, sunlight bent by Earth's atmosphere reaches the Moon, and the Moon looks red.

Here is how to watch with care. Never look straight at the Sun without proper eye protection. This is true even during a partial eclipse, when the Moon covers only part of the Sun. Regular sunglasses are not safe for looking at the Sun. Eclipse glasses are special glasses made for looking at the Sun safely, and a grown-up can give you a pair. A pinhole projector lets you watch an eclipse as a shadow picture, without looking at the Sun through the hole.

Words to know

• umbra: dark center
• penumbra: lighter outer part
• corona: Sun's outer atmosphere
• hybrid: shifting eclipse kind