how are the phases of the moon caused?

Answer 1

Lunar phases are the result of our seeing the illuminated half of the Moon from different viewing geometries: They are not caused by shadows of the Earth on the Moon that occur during a lunar eclipse. The Moon exhibits different phases as the relative geometry of the Sun, Earth and Moon change, appearing as a full moon when the Sun and Moon are on opposite sides of the Earth, and becoming invisible as a new moon (also named dark moon) when they are on the same side. The phases of full moon and new moon are examples of syzygies, which occur when the Earth, Moon and Sun lie (approximately) in a straight line. The time between two full moons (or between successive occurrences of the same phase) is about 29.53 days (29 days, 12 hours, 44 minutes) on average. This synodic month is longer than the time it takes the Moon to make one orbit about the Earth with respect to the fixed stars (the sidereal month), which is about 27.32 days. This difference is caused by the fact that the Earth-Moon system is orbiting about the Sun at the same time the Moon is orbiting about the Earth. The actual time between two syzygies is variable because the orbit of the Moon is elliptic and subject to various periodic perturbations, which change the velocity of the Moon.

It might be naively expected that once every month when the Moon passes between Earth and the Sun during a new moon, its shadow would fall on Earth causing a solar eclipse. Likewise, during every full moon, we might expect the Earth's shadow to fall on the Moon, causing a lunar eclipse. We do not observe a solar and lunar eclipse every month because the plane of the Moon's orbit around the Earth is tilted by about 5 degrees with respect to the plane of Earth's orbit around the Sun. Thus, when new and full moons occur, the Moon usually lies to the north or south of a direct line through the Earth and Sun. An eclipse can only occur not only when the Moon is either new or full, but also when it is positioned at (or very nearly at) the intersection of Earth's orbit plane about the Sun and the Moon's orbit plane about the Earth (that is, at one of its nodes). This happens about twice per year, and so there are between 4 and 7 eclipses in a calendar year. Most of these are quite insignificant; major eclipses of the Moon or Sun are rather rare and newsworthy events.

Answer 2

Sunlight is reflected off the Moon toward Earth. Only the side of the moon facing the Sun will have any light to reflect. So, as the Moon slowly orbits the Earth, the sunlit side rotates in relation to Earth.

When the Moon is on the same side of Earth as the sun, little or no sunlight is reflected because we are looking at the dark side. As the Moon moves around, the lighted portion increases. At a 90-degree angle, we see the "first quarter", when we see exactly half each of the lit and unlit sides of the Moon. When the Moon is on the opposite side of Earth from the Sun, we see the whole sunlit side, the "full" Moon. During the following two weeks, the Moon's lit side turns away from Earth, waning through the last quarter back to the "new" moon.

Additional information: Usually the Moon passes above or below the point exactly in line with or opposite the Sun. When it is in line, there is an eclipse, solar at the new moon, lunar at the full moon. A new Moon always rises and sets with the Sun. A first quarter rises at noon and sets at midight. A full Moon rises at sunset and sets at sunrise. And a last quarter rises at midnight and sets at noon.

On the Moon, a complete "day" lasts 29 1/2 days, the same time it takes for the Moon to orbit the Earth, so the Sun moves very slowly through the lunar sky. Since the Moon always faces the same side toward Earth, the Earth will always be in the same spot in the local lunar sky, wobbling slightly but never rising or setting.

Answer 3

It is the angle of the sun the moon and the earth.. Unless the earth is between the sun and the moon one half of the moon is lit up by the sun and this is changing just as it does on earth by the rotation of the moon itself. But because the moon always shows the same side to us on earth we sometimes see the lit side (a full moon) and sometimes the dark side and we see the stages in-between which are the phases

Answer 4

The phases of the moon are caused by the relative positions of the sun, moon and earth.

If the three are at right-angles, there will be a half-moon.

If the three are in alignment there will be either a full moon or a new moon, depending which order they are in.

Crescent-moons are due to positions between the above.

Answer 5

only 1 side of the moon is lit, hence the phrase and popular pink floyd album 'the dark side of the moon',
the phases of the moon change as more of the bright side comes into view until the full moon and then as less of it until there appears to no moon. this takes approximately 28 days.
there are a 2 factors that cause this,
1st the moons orbit round the earth.
2nd the earths rotational axis, this has also to do with the season or the point of the earth round its orbit of the sun.

Answer 6

The phases of the moon are caused by the rotation of the moon.
It depends on which side of the earth the moon is.You can find out more by going to educative websites.I don't know any good
sites yet.

Answer 7

Moon tiers at the instant are not brought about with the aid of Earth's Shadow.this is simply by its very own shadow and its changing place from earth which shows distinctive factors of the illuminated 50% to wards us. Lunar eclipse is under earths shadow.

Answer 8

Caused by the shadow of the earth as the sun hits it thus causing a reflection onto the moon !

Answer 9

The orbit of the moon around the earth makes the sun shine on it from a different angles. Plenty of pretty pictures here. http://en.wikipedia.org/wiki/Lunar_phase

Answer 10

Turn off the main light in your room (at night, obviously), and turn on a side lamp as the only light source. Hold an orange, tennis ball or similar object at arm's length and turn round slowly, holding it in front of you the whole time.

Observe how the amount of the object which is lit up changes.