Czechs in Ukraine Mostly, they were women with ethnic Ukrainian husbands. Some others stayed of their own choice. During the Soviet era, they were one of the most affected groups by the Chernobyl nuclear power plant disaster in 1986. At the end of the 1980s, ten thousand Czechs lived in Ukraine. At the beginning of the 90s Czechoslovakia invited these remaining Czechs to return to the Czech Republic, which in 1993 almost 2,000 people did, and other people came to the Czech Republic in later years. As of today, Volhynian Czechs are still migrating. In 2014, after the revolution in Ukraine and the
High-altitude nuclear explosion rads/day at four months after "Starfish" for a well-shielded satellite or manned capsule in a polar circular earth orbit, which caused NASA concern with regard to its manned space exploration programs. In general, nuclear effects in space (or very high altitudes) have a qualitatively different display. While an atmospheric nuclear explosion has a characteristic mushroom-shaped cloud, high-altitude and space explosions tend to manifest a spherical 'cloud,' reminiscent of other space-based explosions until distorted by Earth's magnetic field, and the charged particles resulting from the blast can cross hemispheres to create an auroral display which has led documentary maker Peter Kuran