the.com/radio wave
Light too lazy to be visible, carrying your music, memes, and Mars photos anyway.
means An invisible form of electromagnetic radiation with long wavelengths, used to carry signals through air and space without wires.
from 'Radio' traces to Latin radius, 'ray' or 'spoke of a wheel' — the same root as 'radiant' and 'radius.' It entered English via 'radiotelegraphy' in the late 1800s, describing signals sent out in rays rather than along wires, and was soon clipped to just 'radio.' 'Wave' comes from Old English wafian, tied to the motion of water — a fitting borrowing, since these signals ripple outward through space the way water ripples across a pond.
- speed
- travels at light speed, no exceptions
- discovery
- Hertz proved them in 1887, then shrugged at the point
- space use
- Voyager still phones home from interstellar space via radio
- wavelength range
- from football fields long to fingernail short