Tired light is a class of hypothetical redshift mechanisms that was proposed as an alternative explanation for the redshift-distance relationship. These models have been proposed as alternatives to the metric expansion of space of which the Big Bang and the Steady State cosmologies are the most famous examples. The concept was first proposed in 1929 by Fritz Zwicky, who suggested that if photons lost energy over time through collisions with other particles in a regular way, the more distant objects would appear redder than more nearby ones. Zwicky himself acknowledged that any sort of scattering of light would blur the images of distant objects more than what is seen. Additionally, the surface brightness of galaxies evolving with time, time dilation of cosmological sources, and a thermal spectrum of the cosmic microwave background have been observed — these effects that should not be present if the cosmological redshift was due to any tired light scattering mechanism. Despite periodic re-examination of the concept, tired light has not been supported by observational tests and has lately been consigned to consideration only in the fringes of astrophysics.
Read more about Tired Light: History and Reception, Specific Falsified Models
Famous quotes containing the words tired and/or light:
“And you’re too fired up to go to sleep, you sit at the kitchen table. It’s really late, it’s really quiet, you’re tired. Don’t wanna go to bed, though. Going to bed means this was the day. This Feb. 12, this Aug. 3, this Nov. 20 is over and you’re tired and you made some money but it didn’t happen, nothing happened. You got through it and a whole day of your life is over. And all it is—is time to go to bed.”
—Claudia Shear, U.S. author. New York Times, p. A21 (September 29, 1993)
“When the light was extinguished,
She covered me warm,
And she prayed to the angels
To keep me from harm—”
—Edgar Allan Poe (1809–1849)