2013 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. Solar eclipses result from the Moon blocking the Sun relative to the Earth; thus Earth, Moon and Sun all lie on a line. Lunar eclipses work the same way in a different order: Moon, Earth and Sun all on a line. In this case the Earth's shadow hides the Moon from view.
When are this year's solar and lunar eclipses?
April 25: Partial Lunar Eclipse
May 10: Annular Solar Eclipse
An annular solar eclipse will shine above Australia and the South Pacific today. The Moon will cover most of the Sun, but a bright ring of sunlight will encircle the Moon. Hawaii will see a partial eclipse, but the continental U.S. will miss the show.
May 25: Penumbral Lunar Eclipse
A new cycle of eclipses begins tonight as the full Moon just dips its toe in Earth’s faint outer shadow, the penumbra. That shadow will cover just about one percent of the lunar disk, but it is so faint that no one will notice the difference.
October 18: Penumbral Lunar Eclipse
The Moon passes through Earth’s outer shadow this evening. The eclipse is so faint, however, that it is tough to see.
November 3: Solar Eclipse
A total solar eclipse will be visible across a narrow strip of Africa. The far northeastern United States will see a partial eclipse at sunrise.
What is the difference between a lunar and a solar eclipse?
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 only happen 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. 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.