|
The sun may seem like an unchanging ball of plasma, but it′s really a truly amazing aspect of the solar system. Too, there are numerous types of solar phenomena, some occurring on a regular basis and other phenomena which only occurs once in a hundred years or longer.
Viewing such a rare solar occurrence can be a spectacular experience in one′s lifetime and it would be worth taking advantage of any opportunity you get to experience any such solar phenomena.
The Solar Phenomena
There are several types of solar phenomena, including:
aurora, solar eclipse, solar flare, solar halo, solar pillar and solar storm. However, there is only one in this list that is predictable with extremely precise accuracy and that one phenomena is the Solar Eclipse.
The Solar Eclipse
A solar eclipse occurs when a portion of the earth is darkened by the Moon′s shadow as the Moon passes between the Earth and Sun. During any solar eclipse, when the Moon is thus aligned between the Earth and Sun, this always coincides with a
New Moon. The type of solar eclipse depends on how precisely the three celestial objects, Earth, Moon and Sun are aligned in a straight line.
Too, there are other factors that determine what type of solar eclipse will show itself at any given time, below, some of these factors are discussed.
Moon′s Elliptical Orbit
The orbit of the Moon around the Earth is slightly elliptical, and with a distance varying from about 220,000 miles to 250,000 miles, a 30,000 mile difference in distance in it′s monthly journey around the earth. Thus, depending on where the Moon is in it′s orbit, the distance of the Moon to the Earth will determines which type of solar eclipse will occur.
When the orbit of the Moon reaches its
perigee, if all the other requirements for an eclipse are met, the solar eclipse will be a total eclipse. However, when the moon approaches the
apogee in its orbit, a solar eclipse will most likely be an annular eclipse.
What makes the difference in the type of eclipse, is the length of the moon′s
umbra cone, which, when the moon is close to the earth, casts a shadow on the earth. However, when the moon distances itself from the earth, such as when the moon approaches it′s
apogee, the umbra portion of the moon′s shadow does not reach the earth.
(m5pr-sun-shadow) The Shadow of the Moon when at it′s Apogee
The Shadow
The umbra, penumbra and antumbra are three distinct parts of a shadow used to describe the three areas of shadow cast by celestial bodies. Too, these three shadow areas are created by any light source after impinging on an opaque object.
The umbra (Latin: shadow) is the innermost and darkest part of a shadow where the light source is completely blocked by the occluding body. An observer who is within the umbra experiences a total eclipse.
The Penumbra (Latin: almost shadow) is the region in which only a portion of the light source is obscured by the occluding body. An observer in the penumbra experiences a partial eclipse.
The Antumbra (Latin: before shadow) is the region from which the occluding body appears entirely contained within the disc of the light source. An observer in the antumbra experiences an annular eclipse.
Lunar Orbital Nodes
Furthermore, the orbit of the Moon around the earth is not on the ecliptical plane but at an inclination of over five degrees. Thus, total solar eclipses can only occur when the Moon crosses, or is in very close proximity to the ecliptical plane, which only occur twice during each of the Moon′s orbit around the Earth, and which locations are called the Lunar Orbital Nodes.
(m5pr-inclination) The Moon′s Inclination (More about
Orbital Nodes)
When all of the requirement for a solar eclipse are met, then, and only then will there occur a solar eclipse. However, when it comes to solar eclipse, much more is in play to determine what type of eclipse occurs.
What Factors are involved in Determining the types of Solar Eclipses?
The type of solar eclipse that occurs depends on the following factors:
The relative positions of the Earth, Moon, and Sun. These three celestial objects must be in a perfectly aligned, which is a situation known as syzygy. Exactly how they align determines what kind of eclipse is seen. When the Moon passes between the Sun and Earth, we may see a Solar Eclipse. When the Moon is in opposition to the Sun, we may see a Lunar Eclipse.
Other factors include the position of the Earth in its elliptical orbit around the Sun, the position of the Moon in its elliptical orbit around the Earth, the proximity of the Moon to the nearest orbital node, the tilt of the Moon in its orbit and the location on Earth from which the eclipse is viewed.
So, to see a Solar Eclipse, the moon must be in the new moon phase.
Requirements for a Solar Eclipse:
1. The moon must be in New Moon Phase.
2. The Earth, Moon, Sun alignment must be in Syzygy.
3. The Moon must be in proximity of an orbital node.
4. To see the eclipse, a person must be in the path.
For More of the Story
Click on one of the below types of Solar Eclipses.
|