Ernst Öpik
The Estonian astronomer who studied meteors for half a century, predicted that comets come from a vast distant cloud, and worked at Armagh in Northern Ireland.
Key facts
- Born
- 1893
- Died
- 1985
- Nationality
- Estonian
- Field
- Astronomer
Ernst Julius Öpik was born in Estonia and became one of the most original astronomers of the twentieth century. He worked in Tartu, spent time at Harvard, and after fleeing the Soviet advance in 1944 he settled in 1948 at Armagh Observatory in Northern Ireland, where he worked for the rest of his career.
Meteors were one of his lifelong interests. In the early 1930s he led an expedition to Arizona to count and time meteors, and he developed the theory of how meteoroids heat up, glow and lose mass as they plunge through the air. His book on the physics of meteor flight, published in 1958, was a standard work.
In 1932 Öpik suggested that comets come from a huge cloud of icy bodies far beyond the planets, held loosely by the Sun's gravity. The Dutch astronomer Jan Oort developed the same idea in 1950, and it is now called the Oort cloud, or sometimes the Öpik–Oort cloud.
Öpik also calculated how often Earth is struck by asteroids and comets and how big the resulting craters should be, early work in the study of impact hazards. He was the grandfather of the British politician Lembit Öpik, who campaigned on planetary defence.