One of the treasures of the American Museum of Natural History’s permanent collection is a large piece of extra-terrestrial rock called the Willamette Meteorite. At 15.5 tons, it is the largest meteorite ever found in the United States, and the sixth largest in the world.
The Willamette Meteorite is mostly composed of iron and nickel, and like all iron meteorites, it was formed billions of years ago when the solar system was still forming out of cosmic dust. Gravity caused these dust particles to come together to form protoplanets and heavier metals like iron and nickel sank into the interior to form the core. Some time later, this protoplanet must have collided with another planetary body, causing it to fracture, sending chunks of rocks rich in iron and nickel out into space.
Credit: Mike Cassano/Flickr
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