The Moon has always been a source of fascination and scientific inquiry. Though often perceived as a barren, airless rock, recent research reveals that the Moon has a very thin atmosphere known as an exosphere.
Also Read: Possible Signs of Life in Venus’s Atmosphere, Scientists Reveal
The Moon’s atmosphere is not like Earth’s, it is a thin layer of gases known as an exosphere. This exosphere is composed of atoms loosely bound by gravity, which can easily escape into space.
The Moon’s atmosphere is constantly being replenished due to its weak gravity, which allows atoms to drift away continuously.
Discovered during the Apollo missions of the 1960s and 1970s, the lunar atmosphere puzzled scientists for decades.
Initial theories suggested space weathering processes as the primary contributors to the lunar exosphere.
Recent studies have identified meteorite impacts as the major contributors responsible for about 70% of the Moon’s atmosphere.
This process was known as impact vaporization, which involves meteorites striking the lunar surface, vaporizing elements and releasing atoms into the exosphere.
Meteorite bombardment vaporizes specific atoms upon contact, ejecting them into the exosphere. The Moon’s surface has been bombarded throughout its 4.5 billion-year history, first by large meteorites and more recently by micrometeoroids.
The remaining 30% of the atmosphere is attributed to solar wind sputtering. This process involves charged particles from the Sun hitting the lunar surface, releasing atoms and contributing to the atmosphere.
Researchers examined 10 lunar soil samples from the Apollo missions to determine the relative contributions of impact vaporization and solar wind sputtering.
They focused on isotopes of potassium and rubidium, elements easily vaporized by these processes. The analysis showed that lighter isotopes are more likely to be released into the exosphere, while heavier isotopes settle back into the soil.
The research team developed a mathematical model to analyze the isotopic compositions and quantify the contributions of each process.
The model confirmed that meteorite impacts are the dominant process, accounting for about 70% of the lunar atmosphere.
The Moon’s exosphere is extremely thin and delicate. It consists of atoms bouncing around the surface, creating an almost negligible atmospheric presence.
Since the 1980s, scientists have observed this thin atmospheric layer speculating about its origins and sustainability. However the processes involved remained elusive until recent research showed the primary mechanisms involved.
A study led by Nicole Nie from the Massachusetts Institute of Technology (MIT) provides definitive evidence that meteorite impact vaporization is the process responsible for creating and maintaining the lunar exosphere.
The Moon has been continuously bombarded by space rocks over billions of years. This bombardment causes impact vaporization, where the energy from impacts vaporizes lunar soil, releasing atoms into the atmosphere.
Also Read: Komodo Dragons have Iron-Coated, Serrated Teeth, Study Reveals
This process is ongoing, meaning the Moon’s atmosphere reaches a steady state as it is constantly replenished by small impacts across its surface.
In its early history the Moon faced frequent and massive meteorite impacts due to the environment of the infant solar system. These large collisions shaped the lunar surface.
As the solar system evolved, larger space rocks broke down into smaller particles known as micrometeoroids, which continue to bombard the Moon today. Despite their size these tiny impacts are sufficient to sustain the process of impact vaporization.
To understand the mechanisms behind the Moon’s atmosphere, researchers analyzed lunar soil samples collected during NASA’s Apollo missions.
These samples provide invaluable data on the isotopic composition of elements within the soil.
The study focused on two volatile elements, potassium and rubidium, which are easily vaporized. By examining their isotopic ratios, researchers could infer the processes contributing to the lunar exosphere.
The team discovered that the soil samples contained heavier isotopes of both elements. This finding supports the idea that impact vaporization is the primary process, as heavier isotopes are more likely to remain in the soil while lighter isotopes are lofted into the atmosphere.
Another process, ion sputtering was considered as a potential contributor to the Moon’s atmosphere. Ion sputtering occurs when charged particles from the solar wind strike the lunar surface, ejecting atoms into space.
NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) mission provided data indicating that both impact vaporization and ion sputtering play roles in shaping the lunar atmosphere.
The study found that impact vaporization accounts for approximately 70% or more of the Moon’s atmosphere, while ion sputtering contributes around 30%. This quantification clarifies the relative importance of each process.
Also Read: Stress in Humans can Affect Dogs Mood and Choices, Study Reveals
