A new study suggests that particles from Earth’s atmosphere have been swept into space by solar wind and deposited on the Moon for billions of years, becoming mixed into its soil.
This finding helps explain a long-standing mystery dating back to the Apollo missions, which returned lunar samples containing traces of water, carbon dioxide, helium, and nitrogen embedded in the Moon’s dusty surface.
Rethinking the Source of Lunar Substances
A 2005 study suggested these substances may have originated from Earth’s early atmosphere before its magnetic field formed 3.7 billion years ago. Scientists previously believed that once this magnetic field developed, it would have blocked such particles from escaping into space.
However, the new study challenges that idea, suggesting Earth’s magnetic field may have actually aided the transfer of atmospheric particles to the Moon—a process that is still happening today.
As a result, Earth has likely been supplying gases like oxygen and nitrogen to the Moon’s surface throughout its history, according to physicist Eric Blackman, a coauthor of the study.
NASA
He explained that scientists have long believed the Moon formed after an asteroid struck the early Earth, a process that likely allowed volatile elements to transfer between the two. However, the new findings indicate that this exchange has continued for billions of years.
The existence of important elements like oxygen and hydrogen on the Moon’s surface could be valuable for future exploration.
Blackman noted that future lunar missions—and any potential colonies—would likely need to rely on resources available on the Moon rather than transporting everything from Earth.
Harnessing Lunar Resources for Fuel and Exploration
Researchers are exploring ways to extract water and nitrogen from lunar soil for fuel, turning space-delivered materials into valuable local resources.
NASA
The study simulated two scenarios: strong solar wind without a magnetic field and weaker solar wind with a strong magnetic field. These setups represented early Earth and present-day Earth. The results showed that the modern Earth scenario was more effective at sending atmospheric particles to the Moon.
The team then compared their findings with data from earlier analyses of lunar soil. They used samples collected during the Apollo 14 and Apollo 17 missions to confirm their results. Lead author Shubhonkar Paramanick analyzed how solar wind moves Earth’s atmospheric material to the Moon. Nature Communications Earth & Environment published the study.
Earth’s Magnetosphere
Earth’s magnetic field, generated by its molten core, extends into space and shields the planet from solar wind. This interaction forms the magnetosphere, a structure shaped like a comet with a compressed front and a long tail. When solar particles travel along this field near the poles, they produce auroras—the northern and southern lights.
Earth’s magnetosphere channels solar wind, sending more atmospheric particles to the Moon than in early unmagnetized conditions, according to Eric Blackman.
He explained that the magnetic field is not entirely protective for two reasons. First, it exerts pressure that slightly expands Earth’s atmosphere, giving solar wind greater access. During the full moon, the Moon passes through the magnetotail, allowing atmospheric particles a direct path to its surface.
Moon’s Monthly Passage Through the Magnetotail
For a few days each month, the Moon passes through this magnetotail, allowing these particles to settle onto its surface. Because the Moon lacks an atmosphere, the particles are not blocked and instead become embedded in the soil.
The study emphasizes that the Moon may hold a chemical record of Earth’s ancient atmosphere.According to Blackman, the composition of that atmosphere is closely tied to how life evolved throughout Earth’s history.
Kentaro Terada of Osaka University welcomed the theoretical support for his 2017 study showing that solar wind and Earth’s magnetic field can deliver oxygen to the Moon.
He noted that scientists have long understood that Earth and the Moon have evolved together physically since their formation. Lunar meteorites and solar wind particles suggest Earth and the Moon have exchanged materials chemically. He added that the study offers an especially compelling and thorough look at Earth’s history.
Simeon Barber, a senior research fellow at Open University, said the Moon preserves important evidence about Earth’s history and evolution, and that this study strengthens that idea.
He noted the research is timely, with new lunar soil samples from Chang’e-5 and Chang’e-6 helping to test the findings.
Barber also noted that the study will help scientists better interpret data from future robotic missions designed to directly measure volatile elements in lunar soil.
Read the original article on:cnn
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