The Soviet Union beat the US to this, with the October 4, 1957 orbiting of Sputnik 1, and later beat the US to the first human in space, Yuri Gagarin, on April 12, 1961. The race peaked with the July 20, 1969 US landing of the first humans on the Moon with Apollo 11.
The definition of a luminary is an object giving off light, or a personality that is well known or enlightening to mankind. An example of a luminary is a candle.
Cognitive Psychology: Attention Â· Decision making Â· Learning Â· Judgement Â· Memory Â· Motivation Â· Perception Â· Reasoning Â· Thinking-Cognitive processes Cognition-Outline Index. Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminosity is candela per square metre (cd/m 2). Luminance is often used to characterize emission or reflection from flat, diffuse surfaces.