Blue Shift
A blueshift is any decrease in wavelength (increase in frequency); the opposite effect is referred to as redshift. In visible light, this shifts the color from the red end of the spectrum to the blue end. The term also applies when photons outside the visible spectrum (e.g. x-rays and radio waves) are shifted toward shorter wavelengths, as well as to shifts in the de Broglie wavelength of particles. Blueshift is most commonly caused by relative motion toward the observer, described by the Doppler effect. An observer in a gravity well will also see infalling radiation gravitationally blueshifted, described by General Relativity in the same way as gravitational redshift. In a contracting universe, cosmological blueshift would be observed; the expanding universe gives a cosmological redshift, and the expansion is observed to be accelerating.
Read more about Blue Shift: Doppler Blueshift, Gravitational Blueshift
Famous quotes containing the words blue and/or shift:
“The blue we bathe in is the blue we breathe. The blue we breathe, I fear, is what we want from life and only find in fiction. For the voyeur, fiction is what’s called going all the way.”
—William Gass (b. 1924)
“There is a certain relief in change, even though it be from bad to worse; as I have found in travelling in a stage- coach, that it is often a comfort to shift one’s position and be bruised in a new place.”
—Washington Irving (1783–1859)