Sahara Rock Is a Martian Meteorite Among the Oldest Ever Found, Study Says

A rosy stone found in the Sahara Desert in 2022 has turned out to be a piece of Mars that formed at least 4.1 billion years ago, making it one of the oldest known Martian samples. The findings were published Oct. 29 in the journal Science, according to Smithsonian Magazine.

The meteorite, named Teghaza 001, gives researchers a new window into what the Red Planet was like in its youth. Its chemistry also adds to evidence that Mars was once a much wetter place than the dry, dusty world it is today.

The key numbers behind the discovery

• 4.1 billion years: The minimum age of the rock that formed Teghaza 001, based on the study. Mars itself formed around 4.5 billion years ago.
• Nearly two pounds: The size of the Sahara find, which was first spotted in 2022.
• More than 400: The number of Martian meteorites scientists know of. Until now, only two of them offered snapshots of a young Mars.
• More than 4.3 billion years: The age of fragments inside Northwest Africa 7034, one of those two earlier meteorites. The other, Allan Hills 84001, is dated at 4.1 billion years old.
• 13: The number of possible origin locations on Mars that match the meteorite’s composition, according to a NASA statement.

How scientists dated the rock

Yang Liu, a geologist at NASA’s Jet Propulsion Laboratory and a study co-author, and her colleagues examined zircon crystals inside the meteorite. The crystals contain uranium, and researchers commonly date rocks by measuring how uranium decays into lead. The team also analyzed different forms of rubidium and strontium in the meteorite, which produced a similar age estimate.

Liu told Scientific American the team is holding a piece of rock dated even before the oldest rock on Earth. She described it as a piece of Mars so ancient that it existed when life had just started on Earth.

Why this meteorite stands out from the other two

Age is not the only unusual feature. Unlike the other two oldest known Martian meteorites, Teghaza 001 contains volcanic minerals showing it began as magma. It cooled and hardened into part of Mars’ crust, its outermost layer, and was later altered by underground water, according to chemical analyses.

Alicia Cruz-Uribe, a geochemist at the University of Maine and a study co-author, said in a statement that a third sample with distinct geochemistry lets scientists see a different part of Mars’ ancient history. She said it sheds light on what the planet’s mantle looked like and what mantle sources existed.

What this means for the search for life on Mars

All known organisms need water, which is one reason researchers think Mars could once have hosted life. Lee Saper, a geochemist at NASA’s Ames Research Center and the Bay Area Environmental Research Institute, told Reuters the findings support the idea that early Mars had the ingredients and conditions to harbor life. He also cautioned that they do not directly answer whether life existed there.

For general readers, the practical takeaway is scientific rather than immediate: the meteorite adds evidence about Mars’ early crust and water history, but it does not show that life ever existed on the planet.

Where on Mars it likely came from

The researchers say Teghaza 001 most likely came from the Noachian southern highlands. Its chemical makeup matches what NASA’s Mars Reconnaissance Orbiter has observed in that region. Pinning down an exact spot remains open, since 13 locations fit the composition.

What scientists still want to know

Arya Udry, a planetary scientist at the University of Nevada, Las Vegas, who was not part of the study, told Scientific American that many questions about the meteorite remain. She said scientists will need more than the pieces of Mars that reach Earth by chance to understand the planet’s evolution.

Because the meteorite’s precise origin is unknown, Udry said, it is another example of why “we need to bring back samples.”

Around Prague, based on reporting by Smithsonian Magazine