Summary: Fifty years ago today, a Nigerian farmer near the village of Zagami was trying to shoo some cows from his corn field when he heard a loud explosion and was rocked by a blast wave. Seconds later, he saw something fall from the sky and slam into the ground just 10 feet away. When he investigated, the farmer found a black rock, weighing about 40 pounds, buried in the ground. This was no ordinary rock, though — it was a piece of Mars. At first, scientists thought the rock was just another meteorite — a piece of debris from an asteroid. But a couple of decades later, they analyzed tiny pockets of gas inside the Zagami meteorite. The amounts of certain forms of argon, nitrogen, and xenon matched those found in the atmosphere of Mars. Later analysis showed that the volcanic rock formed about a billion years ago. It was blasted into space less than three million years ago, when a good-sized asteroid slammed into the Martian surface. After that, the rock looped around the Sun until it ran into Earth — startling a farmer 50 years ago today. But there’s a footnote to the story. In 1997, the Mars Global Surveyor spacecraft entered orbit around Mars. It carried a tiny grain of the Zagami meteorite contributed by one of the mission scientists. Today, the spacecraft is dead and orbiting high above Mars. Eventually, though, its orbit will decay and it’ll hit Mars — returning the speck of the Zagami meteorite to its birthplace. Script by Damond Benningfield, Copyright 2012 For more skywatching tips, astronomy news, and much more, read StarDate magazine.
