The soil samples that the China National Space Administration (CNSA) brought back from the Moon in 2020 are still making waves, even though it has since returned to the Moon and brought back even more lunar samples in the four years since then.
Graphene on the Moon. A team of Chinese scientists recently discovered graphene, a form of pure carbon, in a small piece of lunar soil that China’s Change’-5 probe collected from a volcanic region of the Moon in December 2020.
Using advanced spectroscopy techniques, the team examined a sample the size of a grain of rice. This discovery is significant because it challenges the widely accepted theory of the Moon’s origin, known as the giant-impact theory. This is partly based on the absence of carbon and other volatile elements on the Moon.
The Moon's origin. According to the giant-impact theory, the Moon was formed after the Earth collided with a hypothetical smaller planet called Theia.
The impact caused the vaporized materials to disperse around the Earth, forming a ring of debris that eventually clumped together under the effect of gravity. Then, it became the Moon.
Until now, the low presence of carbon on Earth's closet satellite has supported the giant-impact theory. This is because scientists believe that the impact between Theia and the Earth must have created extremely high temperatures capable of evaporating volatile elements such as carbon.
Surprise, surprise: There’s carbon on the Moon. In fact, it’s found in thin, strong layers of graphene. How? A study, which has not yet been peer-reviewed, published in the journal National Science Review proposes several hypotheses to explain this finding.
One possibility is that the carbon-containing solar wind interacts with the iron-rich volcanic soil on the Moon. Another suggestion is that the Moon has its own carbon capture process, depositing carbon on its surface. Alternatively, the graphene could simply come from the impact of meteorites.
A useful discovery. In any case, this discovery is important for understanding both the Moon’s history and its practical applications on Earth.
Researchers believe that studying how graphene forms on the Moon could help them develop cheaper and more scalable techniques for producing high-quality graphene, which would be revolutionary for several industries.
Image | Wei Zhang et al., CNSA
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