Colony of Paenibacillus vortex. The colonies grow by the movement of bacteria droplets (dots at end of branches) filled with bacteria spinning around a common center like a hurricane. The branches are trails left behind each vortex as it explores the plate
NASA ECHO II S-131 // From Wikipedia: "Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft, launched in 1960 and 1964, was a metalized balloon satellite acting as a passive reflector of microwave signals. Communication signals were bounced off of them from one point on Earth to another."
Pierre and Marie Curie, circa 1890s. Marie Skłodowska-Curie conducted pioneering research on radiation, and was the first woman to be awarded a Nobel Prize, and the only person to be awarded two Nobel Prizes in multiple fields (Physics, 1903, Chemistry, 1911).