There are at least 277 pieces of Martian rock that have been found on Earth. But, so far, only one possible piece of Earth has been found in space. Inside a lunar sample returned by the Apollo 14 astronauts, scientists found a 2g fragment of quartz, feldspar, and zircon. These are all common minerals on Earth but highly unusual on the Moon.
It’s possible that the rock formed on Earth about four billion years ago and was launched into space by an impacting asteroid or comet. But we can’t be sure – recent research suggests the rock may have a lunar origin after all!
Read more:
- Does the debris around Earth affect the atmosphere?
- How do we know when a rock is from space?
- How much does Earth’s atmosphere weigh?
- How can we tell that a meteorite has come from a particular planet?
Asked by: James Edgell, Oxford
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