births
April 25, 1932
Nikolai Kardashev, Russian astrophysicist (died 2019)

Nikolai Kardashev
Nikolai Semyonovich Kardashev was a Soviet and Russian astrophysicist best known for the Kardashev scale, which measures a civilization's status in technological evolution based on the amount of energy it is capable of harnessing and using. He was also the deputy director of the Astro Space Center of the Lebedev Physical Institute of the Russian Academy of Sciences.