The Earth has got a natural satellite: the Moon. The Moon orbits the Earth, and it completes one orbit every 28 days. The Moon is about 4 times smaller than the Earth. In the Moon there is no air or water, so there is no life.

Like the Earth, the Moon is a non-luminous celestial body, but it can reflect the light from the Sun.

We can only see the part of the Moon that is illuminated by the Sun. That illuminated part depends on the positions of the Moon, the Earth and the Sun. As those positions change, the illuminated part shape also changes. These different illuminated shapes are called the phases of the Moon: new moon, waxing moon, full moon and waning moon.

  • New moon: the Moon is not visible.

  • Waxing moon: the Moon looks like a D. We gradually see more and more of the Moon.

  • Full moon: the Moon is completely illuminated.

  • Waning moon: the Moon looks like a C. We gradually see less and less of the Moon.

Click on the picture to make it bigger.
Phases of the Moon.jpg

If we concentrate the 4 phases in seconds, it will look like this:


If we observe the moon phases during a whole month, the result would look like this:

Moon Phase - Calendar.jpg

Time for the videos.

On the first video you will watch why and how the moon has different shapes (the phases of the Moon).

On the second video you will watch how the Moon was made. Do you know that the Moon was formed after an object about the size of Mars collided with the Earth? The material that was ejected from the Earth formed the Moon.

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