Scientists have discovered that solar radiation may be a more important source of tiny lunar iron nanoparticles than previously thought. Because the moon lacks the protective magnetic field and atmosphere that protects us here on Earth, asteroid impacts and solar radiation affect it in unexpected ways. Asteroids and solar radiation both degrade lunar rocks and soil, resulting in the formation of iron nanoparticles (some smaller, some larger) detectable by instruments on satellites orbiting the moon.
A new study has uncovered crucial clues to help explain the surprisingly active lunar surface. The researchers discovered that solar radiation may be a more significant source of lunar iron nanoparticles than previously thought.
Tiny iron nanoparticles, unlike any found on Earth, are almost everywhere on the Moon, and scientists are trying to figure out why. A new study led by Northern Arizona University doctoral candidate Christian J. Tai Udovicic and associate professor Christopher Edwards of NAU’s Department of Astronomy and Planetary Science uncovered important clues to help understand the surprisingly active lunar surface. The researchers discovered that solar radiation may be a more important source of lunar iron nanoparticles than previously thought in a paper published in Geophysical Research Letters.
The scientists found that solar radiation could be a more important source of lunar iron nanoparticles than previously thought.
Because the Moon lacks the protective magnetic field and atmosphere that protects us here on Earth, asteroid impacts and solar radiation affect it in unexpected ways. Asteroids and solar radiation both degrade lunar rocks and soil, resulting in the formation of iron nanoparticles (some smaller, some larger) detectable by instruments on satellites orbiting the Moon. The researchers used data from NASA and the Japan Aerospace Exploration Agency (JAXA) spacecraft to determine how quickly iron nanoparticles form on the Moon over time.
“We’ve long assumed that the solar wind has only a minor impact on lunar surface evolution, when in fact it may be the most important process producing iron nanoparticles,” Tai Udovicic explained. “Because iron absorbs a lot of light, very small amounts of these particles can be detected from a long distance away, making them an excellent indicator of change on the Moon.”
Surprisingly, the smaller iron nanoparticles appeared to form at the same rate as radiation damage in samples returned from Apollo missions to the Moon, indicating that the Sun has a strong influence on their formation.
“I was shocked when I saw the Apollo sample data and our satellite data side by side for the first time,” Tai Udovicic said. “This study shows that solar radiation may have a much larger influence on active change on the Moon than previously thought, not only darkening its surface, but also producing small amounts of water usable in future missions.”
Understanding the solar radiation environment and potential resources on the Moon is critical as NASA prepares to land the first woman and the next man on the Moon’s surface by 2024 as part of the Artemis mission. Tai Udovicic plans to broaden his targeted study to the entire Moon in future work, recently awarded a NASA Future Investigators in Space Science and Technology (FINESST) grant, but is also eager to take a closer look at mysterious lunar swirls, one of which was recently selected as a landing site for the upcoming Lunar Vertex rover. He also researches lunar temperatures and the stability of water ice in order to inform future missions.
“This work helps us understand how the lunar surface changes over time from a bird’s eye view,” said Tai Udovicic. “While there is still much to learn, we want to ensure that when we return to the Moon, our missions are supported by the best science available. It’s the most exciting time to be a lunar scientist since the 1970s, when the Apollo program was winding down.”
Surprisingly, the smaller iron nanoparticles appeared to form at the same rate as radiation damage in samples returned from Apollo missions to the moon, indicating that the sun has a strong influence on their formation.
“This study shows that solar radiation may have a much larger influence on active change on the moon than previously thought, not only darkening its surface, but also producing small quantities of water usable in future missions,” Udovicic said.
