It’s easy to take the sun for granted. Since before the dawn of man, the sun rises each morning, lights our day, and sets each evening. It sets the pace on the night hours for stargazing, viewing the aurora, or trying to catch a meteor shower. Through it all, the sun rises and sets on its consistent, endlessly perpetuated schedule. Until, that is, the disruption of an eclipse.
As part of this celestial dance, the earth orbits the sun, and the moon orbits us. Eclipses occur when the shadow of the earth crosses the moon, and vice versa. Broadly speaking, there are two types of eclipses: solar eclipse, and lunar eclipses. Within those types, there are three subtypes of solar eclipses and three types of lunar eclipses.
In this post, we’ll break down the different types of eclipses that occur on earth, and how each one looks from our perspective. Hopefully you’ll be inspired to plan a trip to see a solar eclipse, or head outside on the night of a lunar eclipse, to experience one for yourself!
The History of Eclipses
Eclipses have had significant impact on human history. The earliest human record of an eclipse dates back to 2134 BCE; you can find evidence of these notable astronomical events throughout some of the oldest preserved texts in the world.
Solar eclipses were often interpreted as omens. However, the impact depended on the culture and circumstances during which the eclipse occurred. For example, in China eclipses were associated with the health and longevity of an emperor. It was necessary to try and predict them as a result; astronomers who failed to do so were often executed. The Babylonians would place a substitute king on the throne during eclipses. The idea was that the wrath of the gods would fall on him instead of the real king. In ancient Greece, a solar eclipse marked the end of a war between two groups.
These significant historic events, and others, can be tied to recorded eclipses throughout the millennia; even today an eclipse is a significant moment for anyone who experiences it.
How Solar Eclipses Work
A solar eclipse occurs when the moon passes between the sun and earth, casting its shadow on a part of the earth. Depending on the distance between the moon and earth at the time of a lunar eclipse, the moon can actually cast up to two shadows: the penumbra which is a wide, diffuse shadow, and the umbra, which is a smaller, darker shadow.
The 3 Types of Solar Eclipses
Depending on that distance and which of these shadows we experience, we have different names for the three types of solar eclipses: a total solar eclipse, an annular solar eclipse, and a partial solar eclipse.
1. Total Solar Eclipse
A total solar eclipse occurs when the distance between the moon and earth is such that the moon and sun appear the same relative size in the sky. During a total solar eclipse, the moon totally blocks the sun. This creates the umbra shadow (which we call “totality”), and the penumbra in which viewers experience a partial solar eclipse.
During totality, the moon blocks the sun, making the sky go dark and stars appear. Depending on the length of totality, animals are affected by the sudden dusk – and it certainly creates an unforgettable experience for us humans too.
2. Annular Solar Eclipse
An annular solar eclipse occurs when the moon is relatively further from the earth than a total solar eclipse. That is to say, the shadow of the moon does not completely block the sun. The common name for this eclipse is a “ring of fire” eclipse, due to how it looks. Technically, an annular solar eclipse is a special type of partial solar eclipse.
During an annular solar eclipse, no part of the earth falls under the umbra. This means there is no experience of “totality”. Instead, the moon blocks most – but not all – of the sun, creating a dusk that’s not as dark as totality.
3. Partial Solar Eclipse
A partial solar eclipse occurs any time the moon passes between the sun and earth, creating a penumbra shadow on part of the earth. Technically every solar eclipse is a partial solar eclipse at some point and from certain perspectives – so there aren’t any “partial-only” solar eclipses.
How Lunar Eclipses Work
A lunar eclipse can in some ways be thought of as the “opposite” of a solar eclipse. It occurs when the shadow of the earth falls on the moon. Instead of the moon’s penumbra or umbra falling on the earth, the earth’s umbra and penumbra are cast on the moon.
Due to the differences in size between the earth and moon – and the fact that we live on the earth, not the moon, the experience of a lunar eclipse is very different than a solar eclipse.
The 3 Types of Lunar Eclipses
There are three types of lunar eclipse too: a total lunar eclipse, a partial lunar eclipse, and a penumbral lunar eclipse, where the moon falls in the shadow of the earth’s less dramatic penumbra. In both a total and partial lunar eclipse, the moon in the earth’s shadow appears red, earning the nickname “blood moon.”
1. Total Lunar Eclipse
A total lunar eclipse is visible when the earth completely blocks the sun and our umbra is cast on the moon. Interestingly, due to the bending of light around the earth, the earth’s umbra doesn’t create a black shadow (like the moon’s umbra does during a total solar eclipse). Instead, light filters and bends around the earth to create a red shadow on the moon.
2. Partial Lunar Eclipse
Similar to a partial solar eclipse, a partial lunar eclipse occurs when the earth’s umbra is cast on only part of the moon. Also like a total lunar eclipse, the umbra creates a red shadow on the moon during a partial lunar eclipse.
3. Penumbral Lunar Eclipse
The third type of lunar eclipse is called a penumbral lunar eclipse. Due to the alignment of the earth and sun, sometimes the moon doesn’t pass through the earth’s umbra – only its penumbra. As the penumbra is a less dense shadow, it doesn’t have the same effect: instead of turning red, the moon just appears dimmer during a penumbral lunar eclipse.
Future Eclipses to Mark on Your Calendar
If you’re sold on trying to see an eclipse now that you understand how eclipses work, here’s a list of the upcoming solar and lunar eclipses. We’ll keep this list updated too, with extra links and guides to help you know where each eclipse is visible (and if you’ll need to travel to see them).
Upcoming Solar Eclipses
- June 10, 2021 (Annular)
- December 4, 2021 (Total)
- April 20, 2023 (Total)
- October 14, 2023 (Annular)
- April 8, 2024 (Total)
- October 2, 2024 (Annular)
- February 17, 2026 (Annular)
- August 12, 2026 (Total)
- February 6, 2027 (Annular)
- August 2, 2027 (Total)
Upcoming Lunar Eclipses
- May 26, 2021 (Total)
- November 19, 2021 (Partial)
- May 16, 2022 (Total)
- November 8, 2022 (Total)
- March 14, 2025 (Total)
- September 7, 2025 (Total)
- March 3, 2026 (Total)
- December 31, 2028 (Total)
- June 26, 2029 (Total)
- December 20–21, 2029 (Total)
Now you’re all set – you know how eclipses work and when to see them! Do you have other questions or comment? Let us know in the comments!