Einstein's special relativity, established in 1905, unified space and time into a four-dimensional continuum. It relies on two core principles: Galileo's relativity and the constancy of light's speed.
It is an extension of Einstein’s special ... weakest of the four known forces of nature – and the only one not explained by quantum theory. Quantum theory and general relativity in fact ...
The theory of relativity encompasses the gravitational force, one of the four fundamental forces in ... His theory of special ...