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4.1.3 The Moon – some facts

The Moon is about 4.5 billion years old. Current thought is that it was most likely formed by a giant impact, as you saw in Week 1.

The distance to the Moon is known accurately due to reflectors that were placed on it during the Apollo missions. The reflectors, part of the Lunar Laser Ranging Experiment, allow lasers to be shone onto the Moon and the time taken for the laser light to get there and back can be measured. It is then possible, using a simple equation, to calculate the distance to the Moon. You can watch a four minute video of Brian Cox explaining just this [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] .

Figure 4 Distance between the Earth and the Moon.

Next, you have a chance to try calculating the distance to the Moon for yourself. It’s a very basic non-scored quiz. Don’t worry if you don’t know some of the answers.


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