ether (physics)

ether or aether, in physics and astronomy, a hypothetical medium for transmitting light and heat (radiation), filling all unoccupied space; it is also called luminiferous ether. In Newtonian physics all waves are propagated through a medium, e.g., water waves through water, sound waves through air. When James Clerk Maxwell developed his electromagnetic theory of light, Newtonian physicists postulated ether as the medium that transmitted electromagnetic waves. Ether was held to be invisible, without odor, and of such a nature that it did not interfere with the motions of bodies through space. The concept was intended to connect the Newtonian mechanistic wave theory with Maxwell's field theory. However, all attempts to demonstrate its existence, most notably the Michelson-Morley experiment of 1887, produced negative results and stimulated a vigorous debate among physicists that was not ended until the special theory of relativity , proposed by Albert Einstein in 1905, became accepted. The theory of relativity eliminated the need for a light-transmitting medium, so that today the term ether is used only in a historical context.

ether In physics, hypothetical medium that was supposed to fill all space and offer no resistance to motion. It was postulated as a medium to support the propagation of electromagnetic radiations, but was disproved.

ether A hypothetical medium once thought to permeate all space, through which electromagnetic radiation supposedly travelled; formerly spelt aether. On the basis of this supposition, the Earth should move with respect to the ether, and it was predicted that the speed of light would vary when measured in different directions. Experiments in the 19th century (e.g. the Michelson–Morley experiment) failed to detect any such variation in speed. The ether is now regarded as unnecessary, since it is recognized that electromagnetic radiation can propagate through empty space.