Lifestyle on Earth may have made its mark on the moon billions of years before Neil Armstrong's famous first step.
Correction by Japan's moon-orbiting Kaguya spacecraft suggest that air atoms from Earth's higher atmosphere bombard the moon's surface for a few days each month. This kind of oxygen onslaught started out in earnest around 2. 4 billion years ago when photosynthetic microbes first blossomed (SN Online: 9/8/15), planetary scientist Kentaro Terada of Osaka University in Nippon and colleagues propose January 30 in Nature Astronomy.
The oxygen atoms get started their incredible journey in the top atmosphere, where they are ionized by ultraviolet radiation, the research workers suggest. Electric fields or plasma waves accelerate the oxygen ions in the permanent magnetic cocoon that envelops Ground. One side of the magnetosphere stretches away from the sun like a a flag in wind. For five days each lunar pattern, the moon passes through the magnetosphere and it is barraged by earthly ions, including oxygen.
Based on Kaguya's measurements of this space-traveling oxygen in 2008, Terada and colleagues estimate that at least 26, 1000 oxygen ions per second hit each square centimeter of the lunar surface through the five-day period. The uppermost lunar soil may, consequently, preserve bits of Earth's ancient atmosphere, the researchers write, though deciding which atoms blew over from Earth or the sun would be difficult.
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