Estonian astronomer whose work
on the nature of meteors and comets was instrumental in the development
of heat-deflective surfaces for spacecraft on their re-entry into the
Öpik was born near Rakvere and studied at Tartu, where he spent
most of his academic career 1921-44. He then moved to Germany, becoming
professor at the Baltic University in 1945. Three years later, Öpik
moved to Northern Ireland, where he eventually became director of the
Armagh Observatory. From 1956 onward he held a concurrent post at the
University of Maryland, USA.
Öpik was the originator of a method for counting meteors that requires
two astronomers to scan simultaneously. His theories on surface events
in meteors upon entering the Earth's atmosphere at high speed (the ablation,
or progressive erosion, of the outer layers) proved to be extremely
important in the development of heat shields and other protective devices
to enable a spacecraft to withstand the friction and the resulting intense
heat upon re-entry.
Much of Öpik's other work was directed at the analysis of comets
that orbit our Sun. He postulated that the orbit of some of these comets
may take them as far away as 1 light year.