A scientific event which captures my interest
and attention is an eclipse. In astronomy, an eclipse
is a complete or partial obscuring of a celestial body by another. An eclipse occurs when three celestial objects become aligned.
There are two distinctly different types of
eclipse phenomena known to astronomers. In the first, the eclipsing body comes between an observer and the eclipsed object while the other celestial object appears to the observer totally or partially covered by the eclipsing object. An example of this is when eclipses of the Sun occur(This is known as a solar eclipse).
A solar eclipse occurs when the Moon,
revolving in its orbit around the Earth, moves across the disk of the Sun so that the shadow of the Moon sweeps over the face of the Earth. No sunlight penetrates the dark,inner part of the shadow (which is known as the umbra). To observers on the Earth within the umbra, the Sun will appear completely covered by the Moon. Such a solar eclipse is said to be total. Since the umbra is narrow at its intersection of the Earth, a total eclipse can be observed only within a
very narrow area which is known as the zone of totality.
Furthermore, because of the relative motion of the bodies, the totality of the solar eclipse last only a short time(less than eight minutes at any one place on the Earth).Eclipses of the Sun occur two to four times a year. In rare instances, more may occur, as in 1935, when there were five solar eclipses.
Eclipses of the second type affect only
planets or natural satellites that are not self – luminous.In this case, the eclipsing body intervenes between the sun and the eclipsed object. The other celestial body remains in view of the observer, but its illumination by the sun is interrupted, and it becomes darkened by entering into the shadow of the eclipsing object. Examples of this kind of eclipse phenomenon are eclipses of the Moon (This is known
as a lunar eclipse).
A lunar eclipse occurs when the Moon travels
through the shadow of the Earth and loses its bright
illumination by the Sun. It can occur only at the time of the full Moon (For example, when the Moon is directly opposite the Sun), because the Earth’s shadow is directed away from the Sun. A lunar eclipse can be seen from any place on the Earth where the Moon is above the horizon. Such an eclipse can be total or partial, depending on the Moon’s position. If the Moon passes through the center of the Earth’s umbra, a total lunar eclipse occurs. Totality may extend up to one hundred minutes, with the entire elapse lasting about three and a half hours.
Solar and lunar eclipses have long been of
interest, because they are readily observable to the unaided eye and offer an impressive view. Primitive people were often fearful of the falling darkness during a total solar eclipse or by the strange sight of the eclipsed Moon.
Accounts of such eclipses are found among the oldest records of history, and the successful prediction of eclipses makes up one of the earliest achievements of the scientific investigation of nature.
A partial lunar eclipse, on the other hand,
is observable when only a part of the Moon passes through the umbra and it normally lasts up to two hours. Lunar eclipses generally occur twice a year. In some years,however, there may be none, while in other years, one or possibly three may take place.
There are many other types of eclipses, but
the solar and lunar eclipses are the most popular ones. They have captured my attention because the solar eclipse caused me to believe that the Sun was completely covered and it was night time even though it was still daytime. I also became interested in lunar eclipse when I found out that it could
cause bodies of water near Japan to rise to high tide and could possibly wash out part of Japan. Overall, I’m pretty fascinated with eclipses and hope to see one occur in the near future.