The discovery of rust on the lunar surface has scientists baffled

Cal Jeffrey

Posts: 3,660   +1,128
Staff member
A head scratcher: The Moon is littered with iron-rich rocks, and even though trace amounts of water ice were discovered near the poles, conditions there are not ideal for forming rust. A crucial component, oxygen, is scarce at best. Solar winds also make it inhospitable for rust formation. Be that as it may, scientists have discovered rust near our only natural satellite's polar regions.

Researchers at NASA's Jet Propulsion Laboratory (JPL) have discovered iron oxide, specifically hematite, on the Moon's surface, and it has them completely baffled. Iron oxide, more commonly known as rust, is a mineral formed when iron (Fe), oxygen (O), and water (H2O) come into contact. Iron oxide is what gives Mars it's reddish hue. The thing that is mystifying about finding rust on the Moon is that the lack of oxygen and the reductive conditions should make it impossible for rust to form.

"It's very puzzling," said Shuai Li, head researcher from the University of Hawaii. "The moon is a terrible environment for hematite to form in."

Li made the discovery when analyzing data from JPL's M3 (Moon Mineralogy Mapper). Li noticed that M3 was picking up "spectra - or light reflected off surfaces - that revealed the Moon's poles had a very different composition than the rest of it." The spectra indicated that the detected mineral was hematite (Fe2O3).

In 2018, scientists confirmed trace deposits of water ice at the Moon's poles. However, the lack of oxygen has the researchers at a loss as to how the rust is forming. NASA JPL planetary geoscientist Abigail Fraeman, co-author of the study recently published in Science Advances, initially thought it must be a mistake.

"At first, I totally didn't believe it. It shouldn't exist based on the conditions present on the Moon," said Fraeman. "But since we discovered water on the moon, people have been speculating that there could be a greater variety of minerals than we realize if that water had reacted with rocks."

Another aspect that adds to the mystery is the reductive conditions found on the lunar surface. Fraeman explains that the sun bombards the Moon with hydrogen via solar winds. Hydrogen acts as a "reducer" that generally prevents oxidation by adding electrons to the minerals. So technically, the hematite should not have formed.

The researchers are not without their theories regarding the phenomena. The Moon does have a small amount of oxygen carried by the Earth's magnetic field. The scientists also believe that dust hitting the lunar surface could be freeing up water molecules allowing them to mix with the ferric minerals.

"It could be that little bits of water and the impact of dust particles are allowing iron in these bodies to rust," said Fraeman.

However, Li and Fraeman said more research was needed to verify this theory.

Image credit: NASA JPL

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Posts: 6,403   +7,198
I will take a wild guess that solar flares sometimes would melt the ice deposits, releasing oxygen that would trigger later rust formations, before evaporating into space.

Uncle Al

Posts: 9,311   +8,487
Orrrrrrr ..... Neil Armstrong might have had a leak in his urine bladder and was dribbling as they rode around, huh, huh, huh ..... yeah, it could happen .....


Posts: 1,729   +892
Last visitors weren't very enthusiastic on recycling I guess. They left their broken ships to rust and kept on colonizing planets fit for their life.


Posts: 6,308   +7,248
#1 It came from space and crashed on the moon and broke apart.

#2 It was ejected into orbit from Earth by an impact.

#3 Other


Posts: 753   +572
Scientists? What kind of scientist doesn't know about galvanic corrosion?
fake news or not real scientists.


Posts: 2,060   +1,280
To everyone saying 'it came from somewhere else':
And it only arrived at the lunar poles?

Scientists? What kind of scientist doesn't know about galvanic corrosion?
fake news or not real scientists.
They thought about that: the solar winds replace the electrons that would be lost during most corrosion processes, including galvanic.

There are three possible, general hypothesis:

1. There is something about geological chemistry that we don't know or fully understand, and there is a way to form hematite that doesn't require oxygen
2. There is something about the current environment of the moon that we don't know or fully understand (perhaps solar radiation is splitting water into its hydrogen and oxygen components, and this is where the oxygen is coming from)
3. There is something about the past environment of the moon that we don't know about (perhaps, when the moon was very young and still molten, it had a thin atmosphere with enough oxygen to form hematite wherever there was water)

The point is, these are people who went through probably a decade of school, have presumably published numerous papers in their fields, and they don't know what caused it. Doubt anyone here has more of a clue than they do.

Lew Zealand

Posts: 2,248   +2,799
TechSpot Elite
Scientists? What kind of scientist doesn't know about galvanic corrosion?
fake news or not real scientists.
Right first time, it's fake news. Here's the title of the 3rd section of the article and it's first sentence:

"Three Key Ingredients

Their paper offers a three-pronged model to explain how rust might form in such an environment."

Here's a key piece of info: if you see the words "scientists" and "baffled" in a headline or tagline, it's made up clickbait.


Posts: 375   +250
I was surprised the article never used the name "Ferrous oxide" for Fe2O3, as distinct from ferric oxide, FeO. I would have thought that would be easier to recognize and understand than hematite, the name of the mineral.


Posts: 10,612   +463
Lots of people know hematite from the shiny metal looking rocks in gift shops. Doesn't surprise me at all they don't use chemical names.



Posts: 753   +572
...the thing is, during galvanic corrosion, oxygen can be a product of reaction, oppening a way for a other types of corrosion...If they are still baffled, maybe they should coat the Moon in antifreeze and see if still happens :D :D :D


Posts: 45   +28
So that just proves there was oxygen and water on the very rusty planet Mars. Thus there was life because oxygen comes from living organisms ( phytoplankton, plants...).
Do I deserve the Nobel prize for this revelation?