On this day in 1984, scientists found a Martian relic hidden in Antarctic ice

On This Day in Space looks back to Dec. 27, 1984, when a rare meteorite from Mars was found in Antarctica. The rock is called Allan Hills 84001 or ALH 84001 for short. A U.S. team of researchers in Antarctica found it in the Allan Hills region.

The team was from the Antarctic Search for Meteorites (ANSMET) program, which is funded by the National Science Foundation.

The space rock is just over four pounds in weight. Research later revealed that the rock was formed on the Red Planet more than 4 billion years ago.

It was a time when lava from Mars was still hot, but eventually it cooled and became solid. Scientists think Mars had water in the form of liquid on its surface back then.

Scientists also determined that the rock was knocked off Mars by a large impact about 17 million years ago. The space journey started after that, and the rock landed on Earth about 13, 000 years ago. It was preserved in cold Antarctic conditions until it was found.

Years later, ALH 84001 was the center of attention due to studies aimed at searching for life on Mars. Those studies being debated, the meteorite is still a significant one. Scientists use it to understand Mars early period, impacts, and surface conditions.
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How the meteorite was found and traced to Mars

The meteorite was found during a field season in Antarctica, where teams walk across ice fields looking for dark rocks. Ice movement and wind help collect meteorites in certain areas, making them easier to spot.

According to ANSMET, “Antarctica is one of the best places on Earth to find meteorites.”

Once the rock arrived in the States, researchers examined its chemical composition. They looked at the gases trapped in the space rock and compared them with the data obtained from a Mars probe.

The gases were the same as the ones in the Martian atmosphere, so the rock had to be from Mars.

Additional work concentrated on the minerals and isotopes in the meteorite. These experiments gave the researchers a lot more precise information about the area from which the rock came on Mars.

A big number of scientists associate it with Valles Marineris, the massive canyon system on the planet.

Radiometric dating showed the rock crystallized more than four billion years ago. This makes it one of the oldest Martian meteorites ever found on Earth.

NASA later explained that the meteorite “provides a direct record of early Mars.” Because Mars itself cannot yet return samples from that time, ALH 84001 remains a rare source of information.

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Why is Allan Hills 84001 still studied?

Interest in ALH 84001 grew in 1996 after a NASA research team published a study on unusual features inside the meteorite. During a public briefing, NASA scientist David McKay said the rock contained “possible evidence of past biological activity on Mars.”

The study described tiny structures, mineral shapes, and chemical signals found within the rock.

Later research showed that these features could also form through non-living processes. As NASA later stated, “none of the findings alone can be considered proof of life.”

Because of this, the question of life remains open, and no final conclusion has been reached.

Even so, the meteorite continues to be valuable. Scientists use it to test new tools and lab methods. It also helps researchers compare Earth-based samples with rocks studied by Mars rovers.

ALH 84001 is also important for understanding how material moves between planets. Its history shows how impacts can eject rocks into space and carry them across the solar system.

Today, the meteorite remains part of ongoing research into Mars’ early environment and the planet’s long-term changes.
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