Forest Ray Moulton
The astronomer whose calculation in 1929 showed that the meteorite that made Meteor Crater must have been largely vaporised.
Key facts
- Born
- 1872
- Died
- 1952
- Nationality
- American
- Field
- Astronomer
Forest Ray Moulton was a professor of astronomy at the University of Chicago, known for his work on the motion of planets and moons and for an early theory of how the Solar System formed.
In 1929 the company led by Daniel Moreau Barringer, which had spent decades drilling for a buried iron mass beneath Meteor Crater in Arizona, asked Moulton to estimate the size of the meteorite. Moulton considered the energy released when a body strikes the ground at many kilometres per second. He concluded that the impact would generate such intense heat and pressure that most of the meteorite would be vaporised or scattered as small fragments.
His report meant there was almost certainly no huge, valuable mass of iron to be mined. It was a heavy blow to Barringer, who died later that year.
Moulton's reasoning was an important step in understanding impacts. It showed that a crater many times larger than the object that made it can be dug by an explosion of energy, not simply by a rock pushing into the ground. That explains why large craters on Earth and the Moon are almost always round, whatever angle the impactor came in at.
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Barringer Crater (Meteor Crater) crater