Ernst Öpik

Ernst Julius Öpik (October 23, 1893 - September 10, 1985) was a notable Estonian astronomer and astrophysicist, who spent the last part of his career (1948-1981) at the Armagh Observatory in Northern Ireland.

Öpik specialized in the study of minor bodies, such as asteroids, comets, and meteors.

In 1932 he postulated a theory concerning the origins of comets in our solar system. He believed that they originated in a cloud orbiting far beyond the orbit of Pluto. This cloud is now known to us as the Oort Cloud.