Solar Eclipses
A total solar eclipse is perhaps one of the most dramatic astronomical events we may witness
during our lifetimes. For a few short minutes during a total solar eclipse, day seems to turn to night.
The sky darkens. The air cools. The nighttime stars become visible. It is no wonder people travel
around the world to see such a spectacular sight!
A solar eclipse only occurs when the new moon passes between Earth and the Sun and the three are
in perfect alignment. Since the Moon's orbit around Earth is slightly tilted compared to Earth's
orbit, this alignment doesn't happen every month. However, when perfectly aligned, the Moon
covers the Sun and its shadow falls on Earth, blocking our view of the Sun. Interestingly, although
the diameter of the Sun is much larger than the diameter of the Moon, from Earth, they appear to be
the same size. The Moon is much closer to Earth and is located at the exact distance needed to
completely block the Sun during a total eclipse.
There are three main types of solar eclipses: total, partial, and annular.
Total Solar Eclipses - During a total solar eclipse, the Sun appears to be completely blocked by the
Moon. The darkest part of the Moon's shadow, called the umbra, traces a narrow path across Earth.
Only those located in the umbra's path will experience a total solar eclipse. The few minutes when
the Sun's light is completely blocked is called totality. Total solar eclipses only occur once every
year or two.
Partial Solar Eclipses - During a partial solar eclipse, part of the Sun appears to be blocked by the
Moon. Partial solar eclipses occur when the larger and less dark part of the Moon's shadow, called
the penumbra, falls on Earth. Partial solar eclipses happen at least a couple times a year. The
penumbra shadow is larger than the umbra, so partial solar eclipses can be seen from more
locations than total solar eclipses.
Annular Solar Eclipses - During annular solar eclipses the Moon is farther from Earth than during
a total solar eclipse. It is too small to completely cover the Sun. A ring of sunlight shines around the
Moon during an annular solar eclipse.
Caution! Never look directly at the Sun! Looking directly at the Sun can cause permanent damage
to your eyes. Normal sunglasses will not protect your eyes! Consider using a simple pinhole camera
to enjoy a solar eclipse safely.
【題組】35. The diagram below shows the alignment of the Sun, Moon, and Earth during a solar eclipse. What do
the ①②③④ stand for?
(A) ①Partial Eclipse ;②Total Eclipse ; ③Umbra ; ④Penumbra
(B)①Total Eclipse ;②Partial Eclipse ; ③Penumbra; ④Umbra
(C)①Annular Eclipse ;②Total Eclipse ; ③Umbra ; ④Penumbra
(D) ①Partial Eclipse ; ②Annular Eclipse ; ③Penumbra; ④Umbra
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