Lunar eclipses occur two to four times each year. Lunar eclipses only occur during full moons, but because the orbit of the moon is tipped five degrees relative to Earth's orbit around the sun, not every full moon results in an eclipse. When an eclipse does occur, it's visible to everyone on Earth's night side.
There are three types of lunar eclipses. The moon's position relative to the umbra, which is the dark center of an eclipse shadow, determines which type is visible.
About 35 percent of lunar eclipses are total eclipses, and they are the best-known and most-watched type. Although direct sunlight is completely blocked by Earth, indirect light still reaches the moon's surface. The earth's shadow filters out blue-colored light, giving the moon a spectacular rust-colored hue.
A partial lunar eclipse occurs when only part of the moon passes through Earth's shadow. Partial eclipses make up about 30 percent of all lunar eclipses, and they are visible to the naked eye.
Penumbral lunar eclipses, which make up about 35 percent of lunar eclipses, occur when the moon passes through the earth's penumbra, which is the partial shadow that is visible around the umbra's periphery. This type of eclipse is difficult to see with the naked eye, and usually is of interest only to astronomers.Learn More
The lunar highlands are elevated areas on the moon that were created by material that accumulated in layers from the ejecta of craters. The highlands are riddled with craters and the rocks found there are thought to be between 3.84 and 4.48 billion years old. These craters were formed by the intense bombardment on the moon in the early days of its existence.Full Answer >
The lunar cycle lasts slightly over 27 Earth days, or the same amount of time it takes the moon to complete one orbit around the Earth and complete one lunar day. The phases of the lunar cycle change based upon the moon's location along its orbit.Full Answer >
A lunar eclipse happens when the Earth passes between the moon and the sun. Lunar eclipses cast a shadow on the moon due to the Earth's location. From the perspective of the moon, the Earth completely blocks the sun.Full Answer >
Scientists believe that lunar maria formed from lava flows caused when the surface of the moon was disrupted by the impacts of gigantic meteors and comets. Maria is the plural of "mare," which is Latin for sea. One of the most famous of the lunar maria is the Sea of Tranquility, which was the site of the first moon landing.Full Answer >