When you think of the moon you might picture a dry, desolate, rocky place, but recent evidence has been putting this idea to the test.
A new study shows the surface of the moon has more water than we thought, suggesting the interior of our natural satellite could hold a deep reservoir of water.
This new finding bolsters the idea that the lunar mantle is surprisingly water-rich, which could make colonising it for future space exploration much easier.
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BIRTH OF THE MOON
Many researchers believe the moon formed after Earth was hit by a planet the size of Mars billions of years ago.
This is called the giant impact hypothesis.
The hypothesis claims the moon is debris left over following an indirect collision between our planet and an astronomical body approximately 4.5 billion years ago.
The colliding body is sometimes called Theia, after the mythical Greek Titan who was the mother of Selene, the goddess of the moon.
But one mystery has persisted, revealed by rocks the Apollo astronauts brought back from the moon – why are the moon and Earth so similar in their composition?
Several different theories have emerged over the years to explain the similar fingerprints of Earth and the moon.
Perhaps the impact created a huge cloud of debris that mixed thoroughly with the Earth and then later condensed to form the moon.
Or Theia could have, coincidentally, been isotopically similar to young Earth.
A third possibility is that the moon formed from Earthen materials, rather than from Theia, although this would have been a very unusual type of impact.
A group of researchers from the Technical University of Dortmund, Germany, used data from the Moon Mapping Mission to search for clues of water in the spectrum of light reflected from its surface.
By looking at which wavelengths of light are absorbed or reflected by the surface, scientists could get an idea of which minerals and other compounds are present.
In a paper published in Science Advances, the authors found there is water present across the whole surface of the moon, at all times of the day.
Previously it had been thought there was only water at the poles, and our current explanation of how water forms on the moon would not explain it being found at all times of the day.