Astronomy of the Moon
The Moon is the only satellite which accompanies the Earth in its path around the Sun. The Moon's diameter is 27% of the Earth's diameter and its mass is 1.23% of the Earth's. It is 384,000km away from us here on Earth. The Moon takes 27.32 days to orbit the Earth (as seen by us against the background of stars). The orbital plane of the Moon lies within 5° of the apparent orbit of the Sun (as seen from Earth).
We only see the Moon from here on Earth by the light which is reflecting upon it from the Sun and this is how we see the phases.
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| Please note proportions of Sun Moon and Earth are not correct |
The Moon always keeps the same face turned towards the Earth. When the Moon is new, the Sun, Moon and Earth are all aligned with the Moon between the Earth and Sun. While the Moon is New and there is no light to illuminate it, the Moon is still visible due to light reflected from the Earth. When the Moon is Full the Earth is directly between the Sun and Moon.
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| New Moon | Waxing Crescent Moon |
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| First Quarter Moon | Waxing Gibbous Moon |
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| Full Moon | Waning Gibbous Moon |
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| Last Quarter Moon | Waning Crescent Moon |
