Alfred Wegener
The scientist best known for continental drift, who also argued in 1921 that the Moon's craters were made by impacts.
Key facts
- Born
- 1880
- Died
- 1930
- Nationality
- German
- Field
- Meteorologist and geophysicist
Alfred Wegener was a German meteorologist and polar explorer. He is famous for his theory of continental drift, published in 1915, which proposed that the continents had once been joined and had slowly moved apart. Most geologists rejected it during his lifetime; it was accepted decades later as part of plate tectonics.
Less well known is his work on the Moon. In 1921 Wegener published a study arguing that the Moon's craters were made by impacts, not volcanoes. He pointed out that lunar craters look nothing like volcanoes on Earth: they are wide and shallow, their floors are often lower than the land around them, and many have central peaks.
To test the idea, he carried out simple experiments, dropping spoonfuls of powdered cement onto a bed of the same powder. The little craters that formed looked strikingly like those on the Moon, complete with raised rims and even central peaks. He argued that the projectiles hit so fast that their energy turned into an explosion.
Like Gilbert before him, Wegener was largely ignored on this. It was not until the space age that the impact origin of lunar craters was proven. Wegener died in 1930 on the Greenland ice sheet, during an expedition to measure its climate.