We know there is ice on the Moon, what is less clear is where it comes from. A new study suggests that indirect waves of electrons from Earth and the Sun contribute to the formation of frozen water on the lunar surface.

These electrons strike the Moon as they enter and exit Earth's magnetic tail, which our planet leaves behind as it travels through space.

Within the magnetotail is a plasma layer of highly charged electrons and ions drawn from the Earth's atmosphere and solar wind radiation from the Sun.

Scientists have previously studied the role that the magnetotail and the larger magnetosphere may play in the formation of water on the Moon. The magnetosphere is formed when the Earth's protective magnetic field repels the Sun's solar wind and then produces various effects.

"This provides a natural laboratory to study the formation processes of lunar surface water," says planetary scientist Shuai Li from the University of Hawai'i at Mānoa.

"When the Moon is outside the magnetic tail, the lunar surface is bombarded by the solar wind. There are almost no solar wind protons inside the magnetotail, and water formation is expected to drop to almost zero."

However, remote analyses show that this is not the case. Earlier studies had suggested that hydrogen ions from the solar wind formed water on the Moon, but it appears that this water continues to form in the magnetotail when the lunar surface is protected from the solar wind.

Researchers think other forces are at work, especially electrons. One of the ways this could happen is if high-energy electrons react with the lunar soil, releasing trapped hydrogen that could then form water.

"There may be additional formation processes or new sources of water in the magnetotail that are not directly related to the implantation of solar wind protons," Li says. "In particular, the radiation of high-energy electrons shows similar effects as solar wind protons."

More observations and experiments on the lunar surface will be needed to come to a definitive conclusion, but this is an interesting suggestion, one of many scientists are exploring to determine where the Moon's water first originated.

There are many reasons why the source of water on the Moon fascinates scientists: It teaches us more about the Moon's past and is vital for understanding how we can live on the lunar surface for a long time.

Li said: "This finding and my previous findings of rusty lunar poles suggest that Mother Earth is strongly connected to the Moon in many unrecognised ways."

 

Source: https://www.sciencealert.com/