Tired light

Light fatigue, even photons aging, is a physical hypothesis, which was set up to explain the occurring at distant celestial bodies cosmological redshift in accordance with a static universe. The cause of a loss of energy of the photons of light on the path from the source to the observer was drawn into consideration, but for which no convincing physical mechanism could be specified. Experimental results speak clearly in favor of the expansion of the universe, ie the expansion of space-time according to the general theory of relativity, and against a static universe. Light fatigue is therefore not considered by the vast majority of scientists as a serious alternative.

History of hypothesis and attempts to justify

At the beginning of the 20th century, it was Max Planck formula, the basis of quantum physics. It says that electromagnetic waves come in indivisible packets, and the higher the frequency of the wave, the more energy possess the packages. Consequently, would light loses energy ( " tired " ), move its frequency to red.

The astronomer Edwin Hubble discovered in 1929 that the light from galaxies all the more shifts to red, the further they are away from us. If the galaxies were moving away from us, one would expect just such a shift. Therefore Hubble suggested the obvious explanation that the galaxies fly apart explosively.

Fritz Zwicky offered in the same year as Hubble to an alternative interpretation of this observation, namely, that light is proportional to the distance traveled loses energy. He first assumed that a " gravitational friction ," an interaction with matter via gravity, could be responsible. Also, the physicist Robert Andrews Millikan praised the elegance of this idea in a letter of 15 May 1952 Grote Reber: " I agree with you that the hypothesis of light fatigue is simpler and less irrational. "

In contrast to the big bang theory, the theory of light fatigue would mean that we live in a static universe. ( The concept of a static universe must not be confused with the steady-state theory, since according to the latter, the redshift is justified as in the Big Bang theory with the expansion of space-time. )

Different mechanisms to explain the light fatigue have been proposed, such as a scattering effect ( Compton effect ), as a side effect of the quantum mechanics of de Broglie or LaViolette.

Current status

Light fatigue was discussed until about the middle of the 20th century as a possible cause of the cosmological redshift, but subsequently considered by cosmologists increasingly as not applicable. The experimental confirmation of the theoretical and consistency of the expansion of the universe models are represented for the light fatigue just outside the scientific mainstream. Arguments against the light fatigue include:

• The observed duration of supernovae correlated with redshift, which is in agreement with the expansion, and the light fatigue contradicts.

• " Tolman surface brightness test " states that in an expanding universe would have to lose more distant celestial bodies and galaxies in brightness while in a static universe, the brightness remains the same, or only to a much lesser extent becomes smaller. In fact, a decrease corresponding to the expansion was observed.

• The observed thermal spectrum of the cosmic background radiation ( black body radiation ) is incompatible with light fatigue, because the photon density would remain the same validity of this hypothesis and make a redshift consequently the spectrum of non- thermal. The conceptual model of the expanding universe guarantees, however, that the background radiation still retains the properties of a black-body radiation.

• In scattering as a cause of fatigue light the image of distant objects would appear blurred, which is not observed. S. 4