The Lunar Eclipse and the Solar Eclipse: What's the Difference?

Eclipses are a fascinating event, steeped in superstition and myth since the ancient times. They have been omens, and prophecies, and have invoked fear and wonder in people since the times of ancient civilizations. Even today, they still invoke wonder and amazement, although they do not cause as much fear as they used to. But, there are two types of eclipses. There is the solar eclipse, and the lunar eclipse. What is the difference? And what causes them? That is the question I seek to answer with this article.

A lunar eclipse is when the moon is shadowed by Earth. For this to happen, the Earth must be between the Sun and the moon. Because of the alignment, a lunar eclipse will only happen on a full moon. It doesn't happen often, because for the Earth's shadow must go directly over the moon. Usually, the moon will go directly over or under the shadow of the Earth, and all you will see is the full moon. Lunar Eclipses happen about twice a year.

The Earth's shadow is split into two different parts. There is the umbra, and the penumbra. The penumbra is the outer part of the shadow. Mostly, the moon will go through or around the penumbra when a full moon comes around. When something is in the penumbra, it is only partially shielded from the illumination of the Sun. The umbra is the center of the Earth's shadow. When something goes through the umbra, it is totally shielded from the Sun's light. When the Moon passes through the umbra, it is shielded from the Sun's light, thus causing a lunar eclipse.

The moon does not go totally dark during an eclipse. This is because the Earth actually refracts light into the moon, illuminating it to a small degree. When the moon goes through a Lunar Eclipse, it can be dark and purple, or it can be illuminated to a reddish color. The red color is caused by interference in the atmosphere, which can scatter shorter light wavelengths, while longer wavelengths can go through more easily. Red is the longest wavelength in the visible spectrum, so it becomes the predominant color.

Solar Eclipses happen when the moon blocks the Sun. For this to happen, the moon must be between the Sun and the Earth, meaning that a Solar Eclipse will always happen during a new moon. Solar Eclipses are rarer than Lunar Eclipses. Technically, they happen about once every eighteen months, but because so much of the world is covered in water, or otherwise inaccessible, most Solar Eclipses go unseen. Also, Solar Eclipses are said to recur in the same spot only every three hundred and fifty years or so.

There are several types of Solar Eclipses. There are total, annular, and partial eclipses. Partial eclipses are when, from your point of view, the Sun is only partially blocked by the Sun, making it look like an oversized Pac-Man. Annular eclipses happen when the apparent size of the moon is smaller then the apparent size of the Sun, making a distinct ring, or corona, where the Sun is directly visible. Total eclipses happen when the moon appears to be the same size or bigger than the Sun and completely blocks it.

Annular Solar Eclipses are dangerous to look at straight on, because even though some of the light is being blocked, the corona is still just as bright. Because the eyes sense a lack of light, the pupils of your eye will open wider, and the still-bright corona will let light straight into your unprotected eyes. Total Eclipses are actually safe to look at, because no light from the Sun is being let past the moon. But, the moment where the moon passes under from the Sun can be dangerous to the eyes, so you need to know exactly when that will happen before looking at a Total Eclipse.

Eclipses are beautiful things, and have amazed people for centuries. They will continue to amaze, and to make people wonder, for centuries to come. And if you are lucky enough to ever be able to see a total Solar Eclipse, then you may count yourself lucky. It will be something you will never forget.