A small rock pulled in by Earth's gravity and picked up from the snow became front-page news when scientists announced it as possible evidence of past life on the Red Planet.
Is there life on Mars? A little rock is stirring up scientific controversy. The rock, a four and a half pound meteorite, is called ALH84001. What makes it so special is that it's a piece of Mars. It was introduced to the world formally on August 7, 1996 at one o'clock in the afternoon. The world may never be the same because there is evidence that shows there might be... life on Mars.
Photo. A full view of ALH84001. Courtesy of NASA.
The rock formed four and a half billion years ago when Mars itself became the fourth planet from the Sun. Scientists at the Johnson Space Center in Houston, Texas think that three and a half billion years ago surface water on Mars seeped into the rock through fractures. When the water entered the rock, it formed deposits with carbonates. Single-cell organisms got trapped in the deposits.
Then, sixteen million years ago a six mile wide object impacted on the surface of Mars. This collision was as powerful as a million hydrogen bombs. The force of the impact threw surface material so high that it escaped Mars's gravitational pull. Debris from Mars started a journey through the solar system.
ALH84001 started floating toward the Sun, but it became side-tracked. Earth's gravity captured this meteoroid and pulled it toward our planet. It hit Antarctica more than 13,000 years ago, but the fun really began just 13 years ago, in 1984. Scientists found hundreds of meteorites. They are easy to find because they stand out in stark contrast on the white ice. It's like hunting for easter eggs in your own basket. Roberta Score found meteorite ALH84001.
In 1985, a scientist pulled the meteorite out of a cooler of nitrogen gas to take pictures, describe it, and weigh it. A thin slice of ALH84001 was used to discover its mineralogy and classify it. At this point, though, scientists had not even known it was from Mars.
Photo. ALH84001, closer up. Courtesy of NASA.
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