The mystery of Mercury's missing meteorites – and how we may have finally found some
Most meteorites that have reached Earth come from the asteroid belt between Mars and Jupiter. But we have 1,000 or so meteorites that come from the Moon and Mars. This is probably a result of asteroids hitting their surfaces and ejecting material towards our planet.
It should also be physically possible for such debris to reach the Earth from Mercury, another nearby rocky body. But so far, none have been confirmed to come from there – presenting a longstanding mystery.
A new study my colleagues and I conducted has discovered two meteorites that could have a Mercurian origin. If confirmed, they would offer a rare window into Mercury's formation and evolution, potentially reshaping our understanding of the planet nearest the Sun.
Because Mercury is so close to the Sun, any space mission to retrieve a sample from there would be complex and costly. A naturally delivered fragment, therefore, may be the only practical way to study its surface directly – making such a discovery scientifically invaluable.
Get your news from actual experts, straight to your inbox. Sign up to our daily newsletter to receive all The Conversation UK's latest coverage of news and research, from politics and business to the arts and sciences.
Observations from Nasa's Messenger mission have inferred the surface composition of Mercury. This suggests the presence of minerals known as such as sodium-rich plagioclase (such as albite), iron-poor pyroxene (for example enstatite), iron-poor olivine (such as forsterite) and sulfide minerals such as oldhamite.
The meteorite Northwest Africa (NWA) 7325 was initially proposed as a possible fragment of Mercury. However, its mineralogy includes chromium-rich pyroxene containing approximately 1% iron. This poorly matches Mercury's estimated surface composition. As a result of this, and other factors, this link has been challenged.
Aubrite meteorites have also been proposed as potential Mercurian fragments. Recent modelling of their formation suggests an origin from a large planetary body approximately 5,000km in diameter (similar to Mercury), potentially supporting this hypothesis.
Although aubrites do not exhibit chemical or spectral (the study of how light is broken up by wavelength) similarities with Mercury's surface, it has been hypothesised that they may derive from the planet's shallow mantle (the layer beneath the surface). Despite ongoing research, the existence of a definitive meteorite from Mercury remains unproven.
Our latest study investigated the properties of two unusual meteorites, Ksar Ghilane 022 and Northwest Africa 15915. We found that the two samples appear to be related, probably originating from the same parent body. Their mineralogy and surface composition also exhibit intriguing similarities to Mercury's crust. So this has prompted us to speculate about a possible Mercurian origin.
Both meteorites contain olivine and pyroxene, minor albitic plagioclase and oldhamite. Such features are consistent with predictions for Mercury's surface composition. Additionally, their oxygen compositions match those of aubrites. These shared characteristics make the samples compelling candidates for being Mercurian material.
However, notable differences exist. Both meteorites contain only trace amounts of plagioclase, in contrast to Mercury's surface, which is estimated to contain over 37%. Furthermore, our study suggests that the age of the samples is about 4,528 million years old. This is significantly older than Mercury's oldest recognised surface units, which are predicted (based on crater counting) to be approximately 4,000 million years.
If these meteorites do originate from Mercury, they may represent early material that is no longer preserved in the planet's current surface geology.
To link any meteorite to a specific asteroid type, moon or planet is extremely challenging. For example, laboratory analysis of Apollo samples allowed meteorites found in desert collection expeditions to be matched with the lunar materials. Martian meteorites have been identified through similarities between the composition of gases trapped in the meteorites with measurements of the martian atmosphere by spacecraft.
Until we visit Mercury and bring back material, it will be extremely difficult to assess a meteorite-planet link.
The BepiColombo space mission, by the European and Japanese space agencies, is now in orbit around Mercury and is about to send back high-resolution data. This may help us determine the ultimate origin body for Ksar Ghilane 022 and Northwest Africa 15915.
If meteorites from Mercury were discovered, they could help resolve a variety of long-standing scientific questions. For example, they could reveal the age and evolution of Mercury's crust, its mineralogical and geochemical composition and the nature of its gases.
The origin of these samples is likely to remain a subject of continuing debate within the scientific community. Several presentations have already been scheduled for the upcoming Meteoritical Society Meeting 2025 in Australia. We look forward to future discussions that will further explore and refine our understanding of their potential origin.
For now, all we can do is make educated guesses. What do you think?
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Ben Rider-Stokes receives funding from the Science and Technology Facilities Council (STFC).
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Engadget
an hour ago
- Engadget
NASA'S James Webb Space Telescope has captured its first direct image of an exoplanet
NASA'S James Webb Space Telescope has captured direct images of a planet outside of our solar system, which is the first time it has accomplished such a feat. This is a very big deal because exoplanets don't put out much light, so researchers typically discover new planets through indirect methods like keeping track of shadows as they pass across a host star. Webb, however, didn't have to do all that. It has directly captured images of a planet called TWA 7 b . Scientists believe the planet is around the mass of Saturn and is located 100 light years away from Earth. To view this content, you'll need to update your privacy settings. Please click here and view the "Content and social-media partners" setting to do so. — NASA Webb Telescope (@NASAWebb) June 25, 2025 The planet is much further away from its star than Earth, so it has a wider orbital period that lasts several hundred years. The planetary system is thought to be around 6 million years old, so we are really getting a snapshot into the early stages of its development. Our sun is considered to be middle-aged and is around 4.6 billion years old. TWA 7 b is ten times smaller than any previous exoplanet to be directly observed with a telescope, according to The Guardian . Typically, planets of this size can't be seen by telescopes, as the light from the host star masks direct observation. The research team, led by Dr. Anne-Marie Lagrange, got around this by making a telescopic attachment that mimicked the results of a solar eclipse. This reduced much of the light emanating from the star to make it easier to observe surrounding objects. The process allowed the team to spot the planet, which appears as a bright source of light with a narrow ring of debris. Lagrange and her team do note that there's still a "very small chance" the images show a background galaxy, but the evidence "strongly points" to the source being a previously undiscovered planet. The first exoplanet was first discovered in 1992. Since that time, nearly 6,000 more have been spotted. Again, the vast majority of these have not been captured with direct imaging. This is just the latest stunning discovery by our good friend James Webb. It recently captured a cosmic phenomenon called an "Einstein Ring," which is when light from one galaxy is bent around the mass of another. Last year, the telescope found the most distant galaxy ever observed . If you buy something through a link in this article, we may earn commission.
Yahoo
an hour ago
- Yahoo
Inhaling Moon Dust Is Somehow Less Toxic Than Urban Air Pollution
During the Apollo missions, NASA operated out of an abundance of caution to ensure that astronauts didn't track back by planet-threatening microorganisms from the Moon. However, the conditions on Earth might be more dangerous to human life in one specific way. A study by the University of Technology Sydney published last month found that moon dust was far less toxic to our pulmonary system than the air pollution someone would encounter in a city. The study suggests that inhaling moon dust won't cause long-term damage to our airways. Tests showed lunar material didn't trigger significant oxidative stress to lung cells, dissuading the fears provoked by the uncomfortable experiences of Apollo astronauts and other NASA personnel after the missions from a half-century ago. Now, if you're in the exclusive club of scientists with access to powdered lunar regolith, I wouldn't whip out your I.D. badge to start snorting lines of moon dust for a laugh. Michaela B. Smith, lead researcher and Ph.D student, said: "Any dust, if you inhale it, you'll sneeze, cough, and have some physical irritation. But it's not highly toxic like silica, where you end up with silicosis from being on a construction site for 10 years. It's not going to be something like that." Read more: These Should Be The Next Mail Trucks When The Post Office Gets Privatized The researchers emphasized the critical difference between mechanical damage and toxicity. Moon dust is still infamously abrasive. The study noted the irregular shape and rough edges of the dust. According to statically-charged lunar dust would stick to space suits during Apollo's moon walks. This became a serious issue when astronauts returned to the Lunar Module. Once inside, the dust would sting the crew's eyes, cause a sore throat and sneezing. The same thing would happen once the flight surgeon unpaced the suit back on Earth. This new research will be used for Artemis III, NASA's first crewed return to the Moon since Apollo 17 in 1972. The mission is still scheduled for 2027 after numerous delays caused by development issues. However, the entire program has been jeopardized by the Trump administration's funding cuts and cancellation of the SLS rocket program. If Artemis continues, there are plans for a permanent human presence on the surface. Without the looming threats of long-term health issues, NASA could use moon dust to build its base on the surface. Want more like this? Join the Jalopnik newsletter to get the latest auto news sent straight to your inbox... Read the original article on Jalopnik.
Wall Street Journal
an hour ago
- Wall Street Journal
Out On the Streets, It's Every Food Robot for Itself
The future of human-robot relations is playing out on city streets and college campuses, and it's looking a bit scary—for the robots. Tasked with delivering late-night pizza and snacks to the couchbound, robots are getting stuck in snow piles or flipped on their backs, and sometimes relying on the kindness of human strangers to get back on track.
