Astronomy

Solar Eclipses Explained Total Eclipse Lunar Eclipse what is an Eclipse Partial Eclipse Solar



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All About Solar Eclipses History is riddled with fables and stories pertaining to the awe-inspiring phenomenon known as a solar eclipse. The ancient Chinese once believed that a giant dragon had swooped down and swallowed the sun, which in retaliation they fired arrows toward the sky, and banged on drums hoping to scare the dragon away. A few centuries later mankind finally discovered the true nature of these spectacular astronomical events, which dispelled any rationalization of it being a supernatural event.

-Moon Shadows-

To fully understand the nature of an eclipse we first must consider the significance of Moon shadows. Each night, there is visible evidence of the phases of the moon, which is why we have cycling, such as the full Moon and the new Moon. Historically, these changes were used to develop the first understanding of time, which later led to the concept of the calendar.

The Moon shadow is made of two parts. The faint outer shell of the shadow is called the Penumbra, and accounts for the more common partial eclipse. Once the penumbra is cast upon the earth, we may still be able to see the partial outline of the sun, which is so bright that without protective filters or using a pinhole projector, it may be harmful to our eyesight.

The second part of the Moon's shadow is the Umbra. This darker inner circle is the only place where a total solar eclipse may become visible. The full umbra basically overshadows the sun, which results are clearly evident here on Earth.

-Solar Eclipse Explained-

So, what is a solar eclipse, and is there any truth to the urban legends surrounding the event? Basically, a solar eclipse is when the sun and the moon align and come into a perfect alignment, which the moon passes between the sun and the earth. During this brief event, the sun almost disappears completely behind the shroud of the moon. The results of this near-biblical event, literally turns day into night, temperatures plunge, and even animals are slightly confused by the effects of this phenomenon.

Now, this is where science and astronomy kicks in. The celestial cycle, also defined as Celestial Mechanics, also explains how we can actually predict a solar eclipse. Since the moon takes approximately twenty-nine and a half days to complete its orbit around the Earth, each cycle during the new Moon phase, the Moon has to pass between the Sun and the Earth. Now, if you take a look at the solar system from the side, you can actually see that the Sun and Moon rarely are in sync, which may explain why eclipses aren't monthly occurrences. So, how often do the Sun and Moon conjoin? Actually it takes seven consecutive orbits to purport a single alignment, which can either be a partial or a total eclipse. Interestingly the moon is quite tiny compared to the sun, which is nearly four hundred times larger, but for that precise moment it may appear of almost equal size. The illusion is much like the game of squishing heads, which is an optical disproportion of the distance between the object and the focal point of our vision.

-Total Eclipse-

As you already may know, most eclipses are only partial events. A total eclipse only takes place once the Sun and the Moon are completely aligned and the Moon's umbral shadow sweeps across the Earth. So, when and where do total eclipses take place? To determine the next total eclipse, astronomers have used the path of the Moon's umbral shadow, which has been deemed the Path of Totality. The umbra itself is somewhere around ten thousand miles long and one hundred miles in width. Approximately 1% of the Earth is covered by the point of Totality, which in order to completely eclipse the sun, the path must be somewhere within the narrow Path of Totality.

Eclipses can occur at nearly any point on the globe, and only one total eclipse takes place within a one or two year interval. Due to the narrow band within the Path of Totality, it is very uncommon for a total eclipse to be seen from any specific location. Basically, in order to view a total eclipse from the exact same place, you would need to wait approximately 375 years or more, which is why they are such coveted events. So, if we take Princeton for instance, which witnessed its last total eclipse in 1478, the next event is scheduled for May 01, 2079, which is 601 years after.

-Annular Eclipses-

Since few eclipses are total or perfect Totality, others fall into the category of being an annular eclipse. Obviously the Moon is much smaller than the Sun, so it often doesn't completely cover the entire circumference of the Sun. Once again we would need to review the elliptical path of the Moon's orbit, which varies in distance from around 221 000 to 252 000 miles from our planet. Each time the Moon's orbit brings it closer to the Earth, it may appear much larger than the Sun, which if aligned properly a total eclipse will occur. If the Sun and Moon align at the furthermost orbit, only part of the Sun will be eclipsed, which means the umbral shadow is not long enough to reach the Earth.

This path, much like The Path of Totality, is the path of annularity. During an annular eclipse the Sun's center becomes blocked, which leaves a ring or annulus of blinding sunlight surrounding the Moon. This is why during an eclipse it is important never to stare directly into an eclipse with the naked eye. Annular eclipses can last as long as five to fifteen minutes, and although dangerous to the human eye, eclipses are still a beautiful sight to behold.

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