The moon is quietly absorbing tiny fragments of Earth’s environment — and has been doing so for billions of years, a brand new examine reveals. This shocking case of cosmic cannibalism is because of supercharged photo voltaic winds and, extra importantly, our personal planet’s magnetic subject.
The findings upend a 20-year-old concept about how sure charged particles, often known as ions, ended up on the lunar floor, and will have huge implications for upcoming moon missions, researchers say.
Since 2005, the main concept means that this materials switch might have solely occurred earlier than Earth developed its magnetic subject, or magnetosphere, as a result of this invisible forcefield would have doubtless trapped any atmospheric ions being blown away from our planet.
Nonetheless, within the new examine, printed Dec. 11 within the journal Communications Earth & Surroundings, scientists mixed information from the Apollo samples with laptop fashions simulating the evolution of Earth’s magnetosphere, and located that the switch of atmospheric ions was biggest each time the moon passes by way of our planet’s magnetic tail — the biggest part of the magnetosphere that at all times factors away from the solar. (This alignment happens when Earth will get between the moon and solar, close to the total moon part every month).
The fashions revealed that, somewhat than blocking atmospheric ions from being blown from our planet, the magnetic subject traces inside Earth’s tail act as invisible highways for charged particles, guiding them towards the moon, the place they’re then settled into the lunar regolith.
Which means the switch of atmospheric ions doubtless started shortly after the magnetosphere took form round 3.7 billion years in the past — and is probably going nonetheless occurring at present.
Till now, scientists had assumed that the lunar regolith would solely comprise traces of Earth’s earliest environment. Nonetheless, the brand new examine means that these samples might truly act as a time capsule for our environment and magnetosphere.
“By combining information from particles preserved in lunar soil with computational modeling of how photo voltaic wind interacts with Earth’s environment, we are able to hint the historical past of Earth’s environment and its magnetic subject,” examine co-author Eric Blackman, a theoretical astrophysicist and plasma physicist on the College of Rochester, stated in a assertion.
Because of this, regolith collected throughout upcoming lunar missions — corresponding to NASA’s Artemis program, which goals to place boots on the moon by 2028, and China’s moon missions, which have already returned lunar samples to Earth — might assist researchers fill in gaps in our planet’s geological historical past.
Earth is just not the one photo voltaic system object to lose tiny bits of itself to the photo voltaic wind. Mercury is usually seen with a protracted comet-like tail of mud that’s blown off its floor, whereas the moon additionally has a tail of ablated sodium ions that Earth repeatedly passes by way of.
By additional finding out how Earth loses its environment to the moon, the researchers are hopeful of studying extra about how this may increasingly have occurred elsewhere in our cosmic neighborhood.
“Our examine can also have broader implications for understanding early atmospheric escape on planets like Mars, which lacks a worldwide magnetic subject at present however had one much like Earth previously,” examine lead writer Shubhonkar Paramanick, a planetary scientist on the College of Rochester, stated within the assertion. Future analysis might assist scientists “acquire perception into how these processes form planetary habitability,” he added.
