Why "Ethernet" is named after a debunked scientific theory
In 1973, Xerox PARC engineer Robert Metcalfe invented a system to connect computers in a local network. He named it "Ethernet" as a nod to the "luminiferous aether," a hypothetical, invisible medium that 19th-century physicists believed filled all of space to carry light waves. Metcalfe liked the metaphor: his cable network acted as a passive, omnipresent medium that quietly carried data packets to every connected machine, even though the physics concept had long been proven false.
The Ghost Medium of 19th-Century Physics
To understand why Robert Metcalfe named his network invention after a discredited scientific concept, one must look to the physics debates of the nineteenth century. When physicists established that light behaves as a wave, they encountered a theoretical puzzle. Every known wave in classical physics required a physical medium through which to propagate: sound waves travel through air, and ocean waves ripple across water. By analogy, scientists deduced that light waves traveling across the vacuum of space must also be moving through an unseen substance, which they termed the luminiferous aether (or ether).
This hypothetical ether was imagined to be an all-pervasive, completely passive medium filling every corner of the universe. It was thought to be massless, frictionless, and utterly transparent, yet rigid enough to transmit electromagnetic vibrations at immense speeds without altering or directing them. The theory stood until the famous Michelson-Morley experiment in 1887 failed to detect any evidence of an 'ether wind' as the Earth moved through space. Subsequent developments in physics, culminating in Albert Einstein's special theory of relativity, proved that electromagnetic radiation does not require any medium at all to travel through a vacuum, relegating the luminiferous ether to the history of superseded scientific theories.
Metcalfe's Memo and the Birth of a Metaphor
In May 1973, engineer Robert Metcalfe was working at the Xerox Palo Alto Research Center (PARC), tasked with connecting the laboratory's Xerox Alto personal workstations to one another and to high-speed laser printers. Metcalfe, collaborating with engineer David Boggs and other PARC researchers, designed a system that used a single shared coaxial cable to carry information across the office. When drafting an internal memo outlining the architecture on May 22, 1973, Metcalfe coined the term 'Ethernet.'