by New research has shown that the surface of the moon was rich in water around 4 billion years ago.
The research could be an important step towards a better understanding of the moon’s evolution and could help inform future lunar missions, including NASA’s Artemis 3, which it aims to return humans to the lunar surface no earlier than 2026 and leverage the frozen water found there for a period of time. sustainable presence on the moon.
University of Ontario postdoctoral fellow Tara Hayden was investigating a lunar meteorite, which was once a piece of the moon’s surface, when she discovered the mineral apatite. This common phosphate allowed direct examination of an unknown stage in the moon’s evolution for the first time when the moon was molten.
The study of the meteorite shows that back in the moon’s ancient history there was more water in the moon’s crust than scientists previously believed. “The discovery of apatite in the early lunar crust for the first time is extremely exciting – as we can begin to piece together this unknown phase of the moon’s history,” Hayden said in a statement. “We are finding that the early crust of the Moon was richer in water than we expected, and its volatile stable isotopes reveal an even more complex history than we previously knew.”
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The Apollo lunar samples did not paint the full picture of lunar water
Hayden explained that examining lunar meteorites like the one she studied to find apatite is important to learning more about the moon and may reveal insights not found in the samples returned to the Earth in the 1960s and 1970s as part of the Apollo program. .
When the Apollo lunar samples were first examined, scientists discovered that they were “volatile-poor.” Volatiles are chemicals that evaporate easily at relatively low temperatures; water is relatively volatile, evaporating at 212 degrees Fahrenheit (100 degrees Celsius). This led to the assumption that the moon was “bone dry.”
That assumption was challenged in 2008 when scientists found significant amounts of water and volatiles in glass beads in the Apollo samples, prompting another look. As that study progressed over the past 15 years, other examples such as lunar meteorites raining down on Earth after being freed from the lunar surface by asteroid strikes and other impacts showed that the moon but bone dry during its history.
“Most of what we know about the history of water on the moon comes from the Apollo samples, but those samples are estimated to represent only about five percent of the total lunar surface,” Hayden said. “Until we get more samples back in the upcoming Artemis missions, the only surface samples we have are meteorites.”
While studying one of these lunar meteorites during her studies at the Open University in the UK, Hayden discovered that it held key information about water on the moon that she says is “so critical to our understanding of water-bearing minerals the moon”.
Hayden focused primarily on the mineral apatite, which has fluctuations in its mineral structure, finding it within “ferroan anorthosites” in the sample. Ferron anorthosites are the only known lunar rocks that formed directly from the Lunar Magma Ocean, a slushy sea of molten rock that was on the surface of the moon 4.5 million to 4.3 million years ago.
The discovery of this volatile-rich element in ferro anorthosite indicates that water was present in the mostly molten phases of the moon and allowed researchers to directly study this stage of the moon’s evolution, the first time this was done.
“Unraveling the history of water in the lunar crust that first formed around 4.5 billion years ago is important to improve our understanding of the origin of water in the solar system,” said Mahesh Anand, professor of planetary science and exploration at the University Open. “Ancient rock samples from the moon in the form of lunar meteorites provide an excellent opportunity for such investigations.”
Hayden’s discovery comes at a critical time for lunar science as humanity prepares to return to the moon for the first time in 50 years via Artemis and as moons stay longer in the sky.
Frozen water on the surface of the moon could be used in future missions not only to feed astronauts but also to extract hydrogen from fuel that could be used to return crews back to Earth or which could be used for trips deeper into the solar system, for example to Mars. .
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“It has long been believed that the surface of the moon has dried out over thousands and even millions of years, but there may be more water than we thought on the surface of the moon, and we just have to find a way to remove it. ,” Hayden said.
These new moon discoveries are described in a paper published in Nature Astronomy.
