1974 - 1

Jaan Einasto, Ants Kaasik and Enn Saar showed that beside the ordinary matter the galaxies had large surroundings of unvisible matter.

To make conclusions, the researchers used the movement of satellite galaxies rotating round a galaxy. The unseen or dark matter problem was acutely raised already in 1933 by Fritz Zwicky (1898-1974) who studied the dynamics of the clusters of galaxies and found that in the clusters there should be almost 10 times more invisible matter than the visible one. The problem of the dark (invisible) matter was revitalized in 1974 when Jaan Einasto, Ants Kaasik and Enn Saar in Tartu and Ostriker, Peebles and Yahil in Princeton (USA) showed that beside the ordinary matter (stars, gas, dust) the galaxies have large surroundings of dark matter. Now these surroundings are called halo.

Contemporary powerful space telescopes have also recorded the dark matter surroundings of galaxies

1974 - 2

the telescope with the diameter of 1.5 m was completed at Tõravere.

This is the largest contemporary reflection telescope which is in the Baltic and the Nordic countries, made by the Leningrad Company of Optics and Mechanics.

Building of the observation tower for the 1.5 m mirror telescope of Tõravere, April 1972 (photo G. Ross, EFA 0-72721)