- In physics, spacetime is a mathematical model that combines the three dimensions of space and one dimension of time into a single four-dimensional manifold. Spacetime diagrams can be used to visualize relativistic effects, such as why different observers perceive differently where and when events occur.
- Hippie (Wikipedia)
A hippie, also spelled hippy, especially in British English, is someone associated with the counterculture of the 1960s, originally a youth movement that began in the United States during or around 1964 and spread to different countries around the world. The word hippie came from hipster and was used to describe beatniks who moved into New York City’s Greenwich Village, in San Francisco’s Haight-Ashbury district, and Chicago’s Old Town community. The term hippie was used in print by San Francisco writer Michael Fallon, helping popularize use of the term in the media, although the tag was seen elsewhere earlier.