As seen from
the Earth, a solar eclipse is a type of eclipse that occurs when the Moon passes
between the Sun and Earth, and the Moon fully or partially blocks
("occults") the Sun. This can happen only at new moon, when the Sun and the Moon are in conjunction as
seen from Earth in an alignment referred to as syzygy. In a total eclipse, the disk of the Sun is fully obscured by the Moon.
In partial and annular eclipses only part of the Sun is
obscured.
If the Moon were in a perfectly circular orbit, a little
closer to the Earth, and in the same orbital plane, there would be total solar eclipses every
single month. However, the Moon's orbit is inclined (tilted) at more than 5 degrees to Earth's orbit
around the Sun (see ecliptic) so its shadow at new moon
usually misses Earth. Earth's orbit is called the ecliptic plane as the Moon's
orbit must cross this plane in order for an eclipse (both solar as well aslunar) to occur. In addition, the Moon's actual orbit is
elliptical, often taking it far enough away from Earth that its apparent size is not large enough to block the Sun
totally. The orbital planes cross each year at a line of nodes resulting in at least two, and up to five,
solar eclipses occurring each year; no more than two of which can be total
eclipses. However,
total solar eclipses are rare at any particular location because totality
exists only along a narrow path on Earth's surface traced by the Moon's shadow
or umbra.
An eclipse is a natural phenomenon.
Nevertheless, in some ancient and modern cultures, solar eclipses have been
attributed to supernatural causes or regarded as
bad omens. A total solar eclipse can be frightening to people who
are unaware of its astronomical explanation, as the Sun
seems to disappear during the day and the sky darkens in a matter of minutes.
Since looking directly at the Sun can lead to permanent eye
damage or blindness, special eye protection or indirect viewing techniques are
used when viewing a solar eclipse. It is technically safe to view only the
total phase of a total solar eclipse with the unaided eye and without
protection, however this is a dangerous practice as most people are not trained
to recognize the phases of an eclipse which can span over two hours while the
total phase can only last up to 7.5 minutes for any one location. People
referred to as eclipse chasers or umbraphiles will travel
to remote locations to observe or witness predicted central solar eclipses.
