The solar system's largest known dwarf planet is discovered. The discovery of “Eris” ultimately lead to the International Astronomical Union (IAU) downgrading Pluto, which has roughly the same size, to a dwarf planet.
The Prague Spring begins. The period of political liberalization in Czechoslovakia began with the election of Alexander Dubček as the country's leader.
The Austrian newspaper Wiener Presse reported the discovery by German physicist Wilhelm Roentgen of a type of radiation that came to be known as an X-ray.