This will be the second and final lunar eclipse of A lunar eclipse can occur only at full moon. A total lunar eclipse can happen only when the sun, Earth and moon are perfectly lined up — anything less than perfection creates a partial lunar eclipse or no eclipse at all.
Some understanding of simple celestial mechanics explains how lunar eclipses work. Related: How lunar eclipses work infographic. Because the moon's orbit around Earth lies in a slightly different plane than Earth's orbit around the sun, perfect alignment for an eclipse doesn't occur at every full moon.
A total lunar eclipse develops over time, typically a couple hours for the whole event. Here's how it works: Earth casts two shadows that fall on the moon during a lunar eclipse: The umbra is a full, dark shadow. The penumbra is a partial outer shadow. The moon passes through these shadows in stages. The initial and final stages — when the moon is in the penumbral shadow — are not so noticeable, so the best part of an eclipse is during the middle of the event, when the moon is in the umbral shadow.
Total eclipses are a freak of cosmic happenstance. Ever since the moon formed, about 4. The setup right now is perfect: the moon is at the perfect distance for Earth's shadow to cover the moon totally, but just barely. Billions of years from now, that won't be the case. According to NASA, two to four solar eclipses occur each year, while lunar eclipses are less frequent.
However, while solar eclipses can only be seen along a roughly mile wide path, each lunar eclipse is visible from over half the Earth. Total lunar eclipse : Earth's full umbral shadow falls on the moon.
The moon won't completely disappear, but it will be cast in an eerie darkness that makes it easy to miss if you were not looking for the eclipse. Some sunlight passing through Earth's atmosphere is scattered and refracted, or bent, and refocused on the moon, giving it a dim glow even during totality. If you were standing on the moon, looking back at the sun, you'd see the black disk of Earth blocking the entire sun, but you'd also see a ring of reflected light glowing around the edges of Earth — that's the light that falls on the moon during a total lunar eclipse.
Partial lunar eclipse : Some eclipses are only partial. But even a total lunar eclipse goes through a partial phase on either side of totality. During the partial phase, the sun, Earth and moon are not quite perfectly aligned, and Earth's shadow appears to take a bite out of the moon. Penumbral lunar eclipse : This is the least interesting type of eclipse, because the moon is in Earth's faint outer penumbral shadow.
During an annular solar eclipse, the Earth, moon, and sun's orbits are lined up, resulting in the moon appearing directly in front of the sun, leaving the outer rim of the sun, and not just the halo, visible.
Due to the curvature of the Earth, a hybrid solar eclipse occasionally occurs. During a hybrid solar eclipse, the eclipse appears as annular over part of its path and total over other parts. Hybrid eclipses are extremely rare. The Earth's shadow is composed of the umbral shadow, or inner shadow, where all of the sun's light is blocked from reaching the moon, and the penumbral shadow, or outer shadow, where just part of the sun's light is blocked from reaching the moon.
A total lunar eclipse occurs when the entirety of moon passes through the Earth's umbral shadow and all of the sun's light is prevented from reaching the moon. During a total lunar eclipse, the moon appears to be an extraordinary color of red or orange.
A partial lunar eclipse occurs when just a portion of the moon passes through the Earth's umbral shadow; some, but not all, of the sun's light is prevented from reaching the moon.
The shape of the moon appears partially shadowed, but the moon retains its usual color. Partial lunar eclipses, unlike many other types of eclipses, are generally visible across an entire hemisphere of the planet, rather than only in specific locations.
During a penumbral lunar eclipse, the moon passes through the Earth's penumbral shadow, rather than the Earth's umbral shadow. Light from the sun is prevented from directly reaching the moon, but light from the sun that is reflected by the Earth does reach the moon, resulting in a faint shadowing effect across the visible surface of the moon. 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. 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.
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. 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. 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.
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. 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. A partial solar eclipse occurs any time the moon passes between the sun and earth, creating a penumbra shadow on part of the earth.
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