A Student's Guide to Solar and Lunar Eclipses

Although many people don't realize it, there are several different types of eclipses. There are solar and lunar eclipses, and each of these can be partial or total. There's a lot to learn about each type of eclipse and how eclipses happen, and once you know more about them, you're sure to find them even more amazing.

Solar vs. Lunar Eclipse: What's the Difference?

Interactions of the moon, the sun, and Earth are involved in both a solar eclipse and a lunar eclipse. When the moon moves between Earth and the sun, blocking the sun, it causes what we call a solar eclipse. When Earth is perfectly aligned between the moon and the sun, blocking the sun's light from reaching off the moon, we call it a lunar eclipse. It's important to note that while you can look up at the moon to see a lunar eclipse, you should never stare directly at the sun: If you want to see a solar eclipse, you'll need a special viewer to look through to protect your eyes.

Solar Eclipses

Partial Solar Eclipse

We usually think of solar eclipses as being fairly rare, but the truth is that partial solar eclipses happen quite frequently. We don't usually see them, though, because the sun is so bright that it's not that noticeable when a bit of it is blocked; a significant amount of the sun needs to be blocked before we can see the eclipse. Partial solar eclipses can be seen before a full eclipse or on their own.

Annular Solar Eclipse

An annular eclipse is much rarer than a partial, and it will only be witnessed by people in a small area. This type of eclipse will look like a ring of fire in the sky, as the moon blocks the center of the sun but is not close enough to Earth to block all of the sun's light at once. There will be a significant darkening of the sky during an annular eclipse, but it will not be anywhere near as shockingly dark as it is during a total eclipse.

Total Solar Eclipse

The rarest of the solar eclipses, a total eclipse occurs only when the moon is in its new phase and is close enough to Earth to completely block the light from the sun. A total solar eclipse can be viewed along a narrow strip of Earth, called the path of totality; people outside of this area will see a partial eclipse or no eclipse at all.

Lunar Eclipses

Penumbral Lunar Eclipse

Penumbral eclipses often go unnoticed, as they are simply a shading of part of the moon. In these situations, Earth casts a shadow on one side of the moon, but it's only the lighter edge of Earth's shadow, called the penumbra. The moon is still visible the entire time, but it might look a bit dimmer.

Partial Lunar Eclipse

Partial lunar eclipses can lead up to a total eclipse or occur by themselves. In a partial lunar eclipse, the moon travels into Earth's shadow but is not fully covered by it. The moon will look partially dark as Earth's shadow passes over it.

Total Lunar Eclipse

During a total lunar eclipse, Earth's shadow covers the entire moon. If you watch a total lunar eclipse, you'll see Earth's shadow covering more and more of the moon until totality; at this point, the sun's light will actually be able to pass around Earth, through Earth's atmosphere, giving the moon an odd reddish hue.

How Often Do Eclipses Happen?

Solar Eclipses

Solar eclipses occur at a rate of two to four times a year worldwide. But since the path of totality is fairly narrow, it's rare to be able to see a total solar eclipse without making a special trip somewhere else to see it.

Lunar Eclipses

Lunar eclipses happen two to five times a year. A lunar eclipse is visible from a much larger section of Earth than a solar eclipse and stays visible for a longer time. While a total solar eclipse typically lasts a couple of minutes, a total lunar eclipse will last up to an hour or more, with a partial lunar eclipse happening over several hours.