In this combined image of the Moon Mineral Gygi Mapper (M3) aboard the Indian Space Research Organisation’s Chandrayaan-1 orbiter, blue areas, water is concentrated at the moon’s poles. Coming to the spectrum of rocks there, the researcher found signs of hematite, a form of rust. Credit: ISRO / NASA / JPL-Caltech / Brown University / USGS
While our moon is airless, research suggests the presence of hematite, a type of rust that normally requires oxygen and water. Scientists are confused.
Mars Has long been known for its corrosion. The iron on its surface, combined with the water and oxygen of the ancient past, gives the red planet its color. But scientists have recently been surprised to find evidence that even our most windless moon has rust on it.
A new paper from Science Advances reviews the orbital data of the Indian Space Research Organization’s Chandrayaan-1, which found water ice and mapped various minerals while surveying the lunar surface in 2008. Shuai Lee, lead author of the University of Hawaii, has studied whether the Moon Mineral raji mapper instrument of Chandrayaan-1 or M. Large amounts of water in the data3Is, which was created by NASAJet Propulsion Laboratory in Southern California. Water interacts with rock to produce a variety of minerals, and m3 The detected spectra – or light reflected away from the surface – revealed that the lunar poles have a very different composition compared to the rest.
Excited, Li inhabits this polar spectra. While the lunar surface is filled with iron-rich rocks, however, she was surprised to find a ga match with the descriptive signature of hematite. Minerals are a type of iron oxide or rust, produced when iron oxygen is in contact with oxygen and water. But the moon has no oxygen or liquid water, so how can it be rusting?
Metal mystery
The mystery begins with the solar wind, the flow of charged particles that emanate from the sun, bombarding the earth and the moon with hydrogen. Hydrogen makes it difficult to make hematite. This is what is known as a reducer, i.e. it adds electrons to the material with which it comes in contact. It is the opposite of what is needed to make hematite: for corrosion from iron, it needs an oxidizer, which removes electrons. And while the earth has a magnetic field that protects it from this hydrogen, the moon does not.
“It’s very surprising,” Lee said. “The moon is a terrible environment for hematite to form.” So he turned to her JPL Scientists Abigail Freman and Vivian Sun to help poke at them3No data and confirm the discovery of its hematite.
“Initially, I didn’t believe it at all. That shouldn’t be based on conditions on the moon, “Freeman said. “But when we find water on the moon, people are speculating that if we realize that water reacts with rocks, we may have a larger number of minerals than we realize.”
Upon closer inspection, Freman and Sun became convinced3Its data actually indicate the presence of hematite at the lunar poles. “In the end, Spectra was definitely hematite-bearing, and there’s no need to explain why it’s on the moon,” Sun said.
Three key components
Their papers provide a tripartite model to explain how rust forms in such an environment. For starters, when the moon lacks atmosphere, it is in fact the home of finding the right amount of oxygen. That source of oxygen: our planet. Earth’s magnetic field moves behind the planet like a windmill. In 2007, Japan’s Kaguya Orbiter discovered that oxygen could travel 239,000 miles (385,00 kilometers) from the Earth’s atmosphere to the Moon and reach the rear magnet.
That search matches their data3, Which found more hematite from the side of the moon towards the earth. “This suggests that Earth’s oxygen could drive the formation of hematite,” Lee said. The moon has been away from the earth for billions of years, so it is also possible that more oxygen comes to this rift when the two were close in the ancient past.
Then there is the matter of all the hydrogen delivered by the solar wind. As a reducer, hydrogen gen oxidation should be prevented. But the Earth’s magnet has a mediating effect. In addition to ferring oxygen from our planet to the moon, it blocks 99% of the solar wind during certain periods of lunar orbit (especially when it is in the full moon phase). Rust forms when the occasional windows open during the lunar cycle.
The third part of the puzzle is water. When most of the lunar bones are dry, water ice can be found in shaded lunar pits on the far side of the moon. But hematite was found away from that ice. The paper instead focuses on the water molecules on the lunar surface. Lee has proposed that dust particles that regularly flow to the moon can mix water molecules filled with this surface into the lunar soil with iron. Among these effects heat id can increase the oxidation rate; Dust particles themselves also carry water molecules, planting them on the surface so that they merge with the iron. Only during the right moments – that is, when the moon is exposed to the solar wind and oxygen is present – can a rust-induced chemical reaction take place.
More data is needed to determine how water interacts with rock. That data could also help explain another mystery: the far side of the moon, why small amounts of hematite form, where Earth’s oxygen oxygen should not be able to get there.
More science to come
Framan said the model could also explain the hematite found on other airless bodies, such as asteroids. “It could be that the effect of small pieces of water and dust particles allows this body to become bloody,” he said.
Lee noted that it is an exciting time for lunar science. Nearly 50 years after the last Apollo landing, the moon is again a major destination. NASA plans to send dozens of new equipment and technology experiments to study the moon next year, followed by human missions in 2024 as part of the Artemis program.
JPL is also making a new version of M.3 For orbit it is called a lunar trailblazer. One of its devices is a high-resolution volatile and mineral moon mapper (HVM).3), Will be mapping water ice in a permanently shaded pit on the moon, and will also be able to reveal new details about hematite.
“I think these results suggest that more complex chemical processes are taking place in our solar system than previously thought.” “We can better understand these hypotheses by sending future missions to the moon to test them.”
