Two meteorites discovered in the Sahara Desert could potentially be fragments of Mercury that broke off during a collision in the early stages of the Solar System’s formation. These meteorites exhibit similarities to Mercury’s surface, but also possess distinct characteristics, including the presence of a mineral not previously identified on the planet. While the origin of these rocks remains a mystery, they could serve as valuable analogs for studying the innermost planet.
Unlike Mars, which has sent meteorite samples to Earth for examination, Mercury has not yielded any such specimens. Planetary scientist Ben Rider-Stokes from The Open University in the UK investigated suspected Mercury meteorites and found possible matches in meteorites Ksar Ghilane 022 from Tunisia and Northwest Africa 15915 from Morocco. These achondrite meteorites share similarities with the crust of Mercury, characterized by their composition and mineralogy.
One challenge with these specimens is that their iron-free silicates and oxygen isotopes resemble aubrites, a type of meteorite primarily composed of the translucent silicate mineral enstatite. Aubrites have not been observed on Mercury’s surface, leading to speculation that they may represent a precursor to the planet. It is suggested that Mercury underwent significant changes in its surface composition due to ancient asteroid impacts, resulting in its current cratered appearance.
While the origins of these meteorites remain uncertain, they offer valuable insights into the potential geological history of Mercury and the processes that have shaped it over billions of years.
The meteorites are younger than the most primitive materials in the solar system but older than the smooth plains of Mercury, which make up about a third of its surface and are approximately 3.6 billion years old. While even the 4-billion-year-old regions of the plains do not match the age of the meteorites, it is possible that these meteorites are remnants of Mercury’s crust from before significant collisions occurred that obliterated the rock and exposed the material beneath. The remnants of this crust on Mercury may have gone undetected, leaving us without that knowledge. BepiColombo is expected to reach Mercury by early 2026, where the spacecraft may discover a source of material that matches these enigmatic rocks. Even if the meteorites are not from Mercury, such as Ksar Ghilane 022 and Northwest Africa 15915, they could serve as analogs for the surface of a planet where extreme heat would pose challenges.
