Dark side of the moon - level 3
A camera aboard the NASA satellite has captured the dark side of the moon. This series of images were taken from NASA's deep space climate observatory and showed a view of the far side of the moon as it's lit by the sun and moves in front of the Earth. The images show the moon moving across the Pacific Ocean towards North America. Its far side is revealed, showing a crater.
Observers on Earth only see one side of the moon because it's tidally locked to our planet, meaning its orbital period is the same as its rotation around its axis.
The images of the far side of the moon weren't seen by humankind until a Soviet mission in 1959. While it monitors solar winds, NASA's observatory will capture the dark side of the moon twice each year.
Difficult words: observatory (a special building from which scientists watch the moon, stars, planets and other things in space) observer (a person who observes – watches something), tidal lock (when a side of a moon or a planet always faces another moon or planet), orbital (relating to orbit – the regularly repeated elliptical course of an object), axis (an imaginary line about which something rotates).
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