Blueshift

Blueshift is a term in astronomy for a shift of the spectrum toward shorter wavelengths, when the light comes from the celestial object that is moving towards the observer. The phenomenon is named so because the shift in the spectral lines of a stellar spectrum is towards the blue end of the visible region.

Nearby pages
Bluestem, Bluestocking, Bluestone, Bluesy, Bluet, Bluethroat