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A lowercase z, fractional stretching of a wavelength.
Also known as: Redshift, Cosmological redshift, z
Redshift is the fractional increase in a wavelength, so z = 1 means the wavelength has doubled. It is not a velocity: for distant galaxies it measures how much the universe has expanded since the light left, which is why redshifts above one are perfectly ordinary.
Denotes redshift, the fractional increase in the wavelength of light from a receding or cosmologically distant source.
Contexts: Laboratory
Is not a Doppler velocity at cosmological distances: it measures the expansion factor of the universe since emission.
Contexts: Laboratory
Can exceed one without implying superluminal motion, which the naive velocity reading would wrongly suggest.
Contexts: Laboratory
An italic lowercase letter z, two horizontal strokes joined by a diagonal.