Sachs-Wolfe effect

Also found in: Wikipedia.

Sachs–Wolfe effect

(saks wûlf) The process by which density fluctuations in the early Universe have left an imprint on the cosmic microwave background radiation. It is caused by the interaction of photons with a gravitational field with density fluctuations. This causes small variations in the temperature. It is thought that the ‘ripples' found by the COBE satellite were due to the Sachs–Wolfe effect. The effect was predicted by Rainer Kurt Sachs and Arthur Michael Wolfe in 1967. See also structure formation.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
References in periodicals archive ?
Photons will climb down a hill or out of a valley that's smaller than it was at the outset, ending up with a net loss or gain of energy in what's called the Integrated Sachs-Wolfe effect.
Collaborator Andrew Connolly (University of Pittsburgh) likens the Integrated Sachs-Wolfe effect to a ball rolling through a dip on a flat plane.