Solar eclipses are rare and usually only last a few minutes because the Moon casts only a small shadow Figure below. Birds may begin to sing, and stars will become visible in the sky. During a solar eclipse, the corona and solar prominences can be seen.
A solar eclipse occurs when the Moon passes between Earth and the Sun in such a way that the Sun is either partially or totally hidden from view. Some people, including some scientists, chase eclipses all over the world to learn or just observe this amazing phenomenon. The umbra is the inner, cone-shaped part of the shadow, in which all of the light has been blocked.
In the penumbra, the light is dimmed but not totally absent. Like everything in the solar system except the Sun, the Moon does not produce any light of its own — it only reflects sunlight. As the Moon moves around Earth, different portions of the satellite are illuminated. This causes the phases of the Moon, so that our view of the Moon goes from fully lit to completely dark and back again. It takes about The time between two new Moon phases or two full Moon phases is The difference of The phases of the moon as if the Sun is above the top of this picture with its rays directed downward.
As the Earth rotates on its axis, the areas directly in line with the Moon experience high tides. The places directly in between the high tides are low tides.
There are two high tides and two low tides each tidal day. Since the Earth is rotating on its axis, the high- low-tide cycle moves around the globe in a hour period. When the Sun and Moon are in line, during the new moon and the full moon, their high tides add up and create a spring tide. During a spring tide, high tides are really high, which means that low tides are really low Figure below. A spring tide is the added highs produced by the Moon and Sun and the added lows, creating a large tidal range.
When the Earth and Sun are in line but the Moon is perpendicular to the Earth a neap tide occurs. This happens when the moon is at first or last quarter-moon phase. In a neap tide the difference between high and low tides is not very large since the pull of gravity from the Sun partially cancels out the pull of gravity from the Moon. Neap tides produce less extreme tides than the normal tides Figure below.
A neap tide occurs when the high tide of the Sun adds to the low tide of the Moon and vice versa so the tidal range is relatively small. Skip to main content. Earth, Moon, and Sun. Search for:. This longer period is called the synodic month. It is customary to specify positions of celestial bodies with respect to the vernal equinox.
Because of precession, this point moves back slowly along the ecliptic. Therefore it takes the Moon less time to return to an ecliptic longitude of zero than to the same point amidst the fixed stars. This slightly shorter period is known as tropical month; The tropical month of the Moon is the analogous tropical year of the Sun.
Like all orbits, the Moon's is an ellipse rather than a circle. However, the orientation as well as the shape of this orbit is not fixed. In particular, the position of the extreme points the line of the apsides: perigee and apogee , makes a full circle lunar precession in about nine years.
It takes the Moon longer to return to the same apsis because it moved ahead during one revolution. This longer period is called the anomalistic month. The apparent diameter of the Moon varies with this period, and therefore this type of month has some relevance for the prediction of eclipses, whose extent, duration, and appearance whether total or annular depend on the exact apparent diameter of the Moon.
The orbit of the Moon lies in a plane that is tilted with respect to the plane of the ecliptic: it has an inclination of about five degrees. The line of intersection of these planes defines two points on the celestial sphere: the ascending and descending nodes. The plane of the Moon's orbit precesses over a full circle in about
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