Who discovered water on the moon

A surprise for the researchers: measurements from three space probes show traces of water on the surface of the earth's satellite

The moon

Pasadena (USA) - The surface of the moon was previously considered bone dry. This picture obviously needs to be revised: Measurements from three space probes show clear absorptions in the infrared range, which, according to the researchers, can only be explained by water (H2O) or hydroxyl (OH). The amount of water on the optical surface of the moon could therefore be up to 0.5 percent by weight, the scientists write in the journal "Science".

The rock samples brought from the moon to earth by unmanned probes and the manned Apollo missions in the 1960s and 1970s contained neither water nor water-modified minerals, as are typical for earthly rocks. From this, the researchers drew the conclusion that the moon does not only contain any water on the surface, but also deep in its crust.

The measurements of the Indian lunar probe Chandrayaan-1, the American Saturn probe Cassini and Epoxi - the extension of the American comet mission Deep Impact - now overturn this picture. Because the infrared spectroscopy of all three probes consistently shows a clear absorption on the moon's surface at a wavelength of three micrometers. At this point there is an important oscillation absorption line of the OH group, which is considered an extremely sensitive indicator for the presence of water or hydroxyl. The researchers are therefore certain that the measurements actually show the presence of water on the moon's surface.

But where does this water come from? An outgassing from the interior of the moon would raise the question of why the moon samples show no changes due to the influence of water. According to the scientists, the most likely explanation is that the solar wind generates the water in the rock near the surface. The protons of the solar wind - positively charged hydrogen atomic nuclei - could, according to the thesis, react with oxygen bound in the rock to form hydroxyl and water.

According to the researchers, the discovery of water on the surface of the moon also increases the chances of finding larger amounts of ice in regions at the poles of the earth's satellite that are in eternal darkness. Because in these cold traps, water vapor released from the rock could condense and freeze. For October 9th, NASA is planning the targeted crash of a rocket stage into a crater at the south pole of the moon. A small probe will then cross the gas and dust cloud generated by the impact and look for traces of water.