Chinese scientists have announced a groundbreaking discovery that challenges the widely accepted theory of the moon’s origin. The team from Jilin University has found graphene in lunar soil samples collected by the Chang’e-5 mission about four years ago. This find defies the prevailing giant impact theory, which posits that the moon formed from a collision between Earth and another small planet, resulting in a carbon-depleted moon.
Graphene, a pure form of carbon, contradicts this theory supported by early analyses of Apollo mission samples. The researchers from Jilin University emphasized this contradiction in an unedited manuscript recently published and reported by the South China Morning Post. They referenced a recent Japanese study that also questioned the giant impact theory by demonstrating carbon ion emission fluxes across the lunar surface, suggesting indigenous carbon presence.
To explore the origins of this carbon, the Chinese team studied younger lunar samples, approximately 2 billion years old. They aimed to understand the crystalline structure of the indigenous carbon on the moon. NASA had previously found graphene in moon rocks from the Apollo 17 mission, attributing its presence to meteor impacts rather than solar winds. The Chinese scientists acknowledged that meteorite impacts could contribute to the formation of graphitic carbon, as NASA suggested. They highlighted the need for further in-depth investigation of natural graphene to gain more insight into the moon’s geologic evolution.
Using Raman spectroscopy and other microscopic methods, the team analyzed a tiny moon rock sample from a volcanic region on the moon’s near side. Graphene was found in the form of individual flakes and as part of a “carbon shell” enclosing various elements. The researchers explained that high magnification confirmed the graphite carbon detected by Raman spectra to be few-layer graphene, comprising two to seven layers.
The presence of iron in carbon-rich areas suggests it might have triggered the transformation of earlier carbon materials into graphite. The graphene’s structure indicates formation through high-temperature processes from volcanic eruptions, where iron-bearing lunar soil interacted with carbon-containing gas molecules in solar winds, leading to mineral catalysis. This mechanism implies a carbon-capture process on the moon, potentially leading to the gradual accumulation of indigenous carbon.
The discovery not only casts doubt on existing moon formation theories but also offers potential for developing better, cheaper graphene production methods.
