For eons, Earth has been generously donating parts of its atmosphere to the Moon, which essentially has none of its own.
According to fresh findings, our planet's magnetic field may be the conduit, directing particles from our atmosphere
Ever since the Apollo missions brought back lunar samples, scientists have been puzzled by the surprising amount of
volatile elements detected in the lunar regolith – the fine dust and rocky material that blankets the Moon. While the
solar wind could account for some of these volatiles, it doesn't explain the high concentrations, especially of
nitrogen. Moreover, the constant bombardment of the lunar surface by micrometeorites could also be altering its
Previously, some scientists suggested that Earth's atmosphere could be a source of these elements, but this was thought
to be only possible before Earth developed its protective magnetic field. The assumption was that the magnetic field
would trap most atmospheric particles.
However, a new study by astrophysicists at the University of Rochester challenges that assumption. The team created
computer models simulating two different scenarios: an early Earth without a magnetic field and a strong solar wind, and
a modern Earth with a robust magnetic field and a weaker solar wind.
Surprisingly, the modern Earth model provided a better fit with the observed data. The process works like this: the
solar wind strips charged particles from Earth's atmosphere, and these particles then travel along the planet's magnetic
field lines. Because of the constant pressure from the solar wind, Earth's magnetosphere isn't a perfect sphere;
instead, it resembles a comet's tail. As the Moon orbits Earth, it periodically passes through this magnetotail, during
which particles are deposited onto the lunar surface.
Earlier research hinted at a similar mechanism by which oxygen could be delivered to the Moon, potentially leading to
the formation of water and even rust.
The latest study indicates that this process has been occurring for billions of years, allowing significant quantities
of volatile particles to accumulate in the lunar regolith. Furthermore, given the substantial changes in Earth's
atmosphere over this vast timescale, the lunar surface may hold a valuable record – essentially a time capsule – of our
planet's atmospheric history.
The findings were published in the journal Nature Communications Earth & Environment.