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Lunar and Solar Eclipses
An eclipse is the result of the total or partial masking of a celestial body by another along an observer's line of sight. A solar eclipse occurs when the Moon passes between Earth and the Sun, fully or partially obscuring the Sun's disk. A lunar eclipse occurs when the Moon passes through Earth's shadow, fully or partially darkening the lunar disk.
2023 ECLIPSES
| Date | Type | View from U.S. |
|---|---|---|
| April 20 | Solar: Annular/Partial | None |
| May 5 | Lunar: Penumbral | None |
| October 14 | Solar: Annular | Most of the country |
| October 28/29 | Lunar: Partial | None |
Total lunar eclipse
The Moon is completely covered by Earth’s dark inner shadow, turning the lunar surface dark orange or red.
Partial lunar eclipse
Earth’s shadow covers only part of the lunar disk, so it looks as though something has taken a bite out of it.
Total solar eclipse
The Moon passes between Earth and Sun, completely covering the Sun’s disk along a narrow path.
Partial solar eclipse
The Moon covers only part of the Sun, so the Sun remains visible. Depending on how much of the Sun is obscured, the sky may turn dusky and temperatures may drop.
Annular solar eclipse
The Moon is a bit farther from Earth than average, so a ring of sunlight encircles the Moon as it passes between Earth and Sun.
What is the difference between a lunar and a solar eclipse?
This illustration shows the Moon passing through Earth's shadow during a typical lunar eclipse. The Moon is slightly tinted when it passes through the light outer portion of the shadow, the penumbra, but turns dark red as it passes through the central portion of the shadow, called the umbra. [Tim Jones]
From our perspective on Earth, two types of eclipses occur: lunar, the blocking of the Moon by Earth's shadow, and solar, the obstruction of the Sun by the Moon.
When the Moon passes between Sun and Earth, the lunar shadow is seen as a solar eclipse on Earth. When Earth passes directly between Sun and Moon, its shadow creates a lunar eclipse.
Lunar eclipses can happen only when the Moon is opposite the Sun in the sky, a monthly occurrence we know as a full Moon. But lunar eclipses do not occur every month because the Moon's orbit is tilted five degrees from Earth's orbit around the Sun, so most of the time the Moon passes above or below the shadow. Without the tilt, lunar eclipses would occur every month.
Lunar and solar eclipses occur with about equal frequency. Lunar eclipses are more widely visible because Earth casts a much larger shadow on the Moon during a lunar eclipse than the Moon casts on Earth during a solar eclipse. As a result, you are more likely to see a lunar eclipse than a solar eclipse.
The Moon casts its shadow on Earth's surface during a total solar eclipse. [Tim Jones]