Largest Meteorite Ever Discovered in the US

The 15.5-ton Willamette meteorite formed in the early solar system and hit Earth at more than 64,000 km/h before drifting from Canada to the US.

Two boys sit inside the cavity of the Willamette meteorite. Photo: Amusing Planet — Two boys sit inside the cavity of the Willamette meteorite. Photo: *Amusing Planet*

One of the treasures in the American Museum of Natural History's collection is a large alien rock called the Willamette meteorite. Weighing in at 15.5 tons, it is the largest meteorite ever found in the United States and the sixth largest in the world, according to Amusing Planet .

The Willamette meteorite is made mostly of iron and nickel. Like all iron meteorites, it formed billions of years ago when the Solar System was still forming from cosmic dust. Gravity caused these dust grains to clump together to form a planetary embryo, while heavy metals like iron and nickel sank inside to form the core. Later, the planetary embryo likely collided with another body, causing it to break apart and the iron-nickel-rich rocks to be flung into space.

The fragment of the planetary embryo continued to orbit the Sun for the next several billion years until about 17,000 years ago, when the orbits of Earth and the Willamette asteroid intersected. The asteroid hit Earth at more than 64,000 km/h, over an ice cap in western Canada.

Over the centuries, the slowly shifting glaciers carried the meteorite to Montana, near an ice barrier that formed on the Clark Fork River. This barrier held back a huge amount of water in Lake Missoula. When the meteorite reached the area, the ice dam broke apart, releasing one of the largest floods ever recorded. Trapped in the ice, the meteorite floated down the Columbia River until the ice crust broke off and the alien rock sank to the riverbed, near present-day Portland. At the end of the last Ice Age, the water level dropped, exposing the meteorite. Over thousands of years, rainwater mixed with the iron sulfide in the meteorite to form sulfuric acid, which slowly dissolved parts of the rock, leaving porous holes in its surface.

The meteorite was first discovered by the Clackamas Chinook people, who lived in Oregon’s Willamette Valley before European settlement. They named the meteorite “Tomanowos” and considered it sacred. They used the stone in many rituals, using water from the meteorite’s crevices to purify themselves. Hunters in the tribe also dipped the tips of their arrows in the water before going hunting.

In 1902, a miner named Ellis Hughes saw the meteorite and realized its importance. He spent three months secretly moving the rock to his home and charging admission. When the theft was discovered, the rightful owner sued and got it back. The company sold the meteorite to William Dodge, who donated it to the Museum of Natural History in New York.

The Willamette meteorite remained in the museum’s display for nearly a century. In 1999, the Confederated Tribes of the Grand Ronde Community of Oregon (CTGRC) demanded the return of the Tomanowos. Later that year, an agreement was reached that allowed the meteorite to remain in the museum, but tribal members could hold private ceremonies around the rock once a year.

An Khang (According to Amusing Planet )

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