VCA 7.C. Hubble's Constant and Tired Light

Another line of evidence involves Hubble's constant, which is the very heart of the expanding universe model. As we have seen, according to the big bang model, the further away a galaxy is, the faster it should be going. According to Hubble's law, the speed of recession should be equal to the distance multiplied by a number called Hubble's constant. With this law, it becomes possible for astronomers to calculate the distance of galaxies simply from their red shifts. Find the red shift and divide by Hubble's constant-and now you have the distance.

The constant also gives astronomers the size of the universe. They can measure the red shift of the most distant celestial object and use the Hubble constant to determine its distance. The Hubble constant is therefore an extremely crucial number. For example, if you double the constant, you double the estimated size of the universe. Clearly, a precise value for Hubble's constant is essential for determining the size of the universe with any accuracy.

Over the years, however, different scientists have obtained many different values for Hubble's constant. The constant is expressed in kilometers per second per megaparsec. (A megaparsec is a unit of cosmic distance equal to 3.3 million light-years.) In 1929 the value of Hubble's constant was 500. In 1931 it was 550. In 1936 it was 520 or 526. In 1950 it was given as 260, down significantly. By 1956 it had dropped to 176 or 180. In 1958 it fell much further down, to 75, but in 1968 it bounced back up to 98. In 1972 it ranged from 50 all the way up to 130. Today, the Hubble constant is pegged at 55. All this change led one wry astronomer to say that perhaps the Hubble constant should better be called the Hubble variable.

Of course, these changes over the decades can be explained by arguing that that scientists have improved their methods and refined their calculations. But even so, something appears to be amiss.

This brings us to the work of Jean Pierre Vigier, a French astrophysicist at the Institute Henri Poincare (VG1-5). Vigier points out that even today, different observers obtain different values for Hubble's constant. Tammann and Sandage give 55 plus or minus 5. Abell and Eastmond arrive at 47, plus or minus 5. Then there is van den Bergh, who calculates a value between 93 and 111. Heidmann got 100 for his figure. De Vaucouleurs came up with 100 plus or minus 10.

If the universe is expanding according to some uniform law of proportionality, how is it that so many observers obtain so many greatly different values for the rate of expansion?

Vigier notes that when astronomers take measurements in different directions, they find different rates of expansion. He then points out something even stranger: The sky can be divided into two sets of directions. The first is the set of directions in which many galaxies lie in front of more distant galaxies. The second is the set of directions in which there are distant galaxies without foreground galaxies. Call the first set "area A," and the second set "area B."

Vigier found that if you restrict yourself to the distant galaxies in area A and calculate Hubble's constant, you get one value, and in area B you get a significantly different one. This suggests that the rate of expansion varies depending on whether we measure galaxies with or without foreground galaxies. If the universe is expanding, what could these foreground galaxies possibly have to do with the rate of expansion? Vigier suggests that in fact the measured red shifts of the distant galaxies are not caused by the expansion of the universe at all. Rather, they are caused by something quite different-something called a tired-light mechanism.

According to Vigier, as light moves through space it becomes red shifted simply from traveling a certain distance. This happens in accordance with physical laws, just like any other phenomenon. There is a law requiring that as light travels, it shifts toward the red. The effect is so small that it cannot be readily measured in laboratories on earth, but as light moves the vast distances between galaxies, the effect becomes apparent.

This is called the tired-light hypothesis because the light loses energy as it moves through space. And the more tired it becomes, the redder it becomes. Red shift is therefore proportional to distance, not to the velocity of the object. Vigier pictures the universe as not expanding. All the galaxies are more or less stationary. The red shift is not a Doppler effect; it has nothing to do with the velocity of the light's source. The red shift is caused by an inherent property of the light itself, namely that it becomes tired after traveling long distances.

Most astronomers reject the idea of tired light. In the words of Joseph Silk, of the University of California at Berkeley, "Tired light cosmologies are unsatisfactory because they invoke a new law of physics" (SK).

But Vigier presents his tired-light theory in a way that does not require radically new physics. He proposes that there is a kind of particle in intergalactic space that interacts with light in such a way as to steal energy from it. In the vicinity of massive objects, there are more of these particles than elsewhere. Using this idea, Vigier explains the different red shifts for the A and B regions in the following way: The light passing through foreground galaxies encounters more of these particles and therefore loses more energy than light not passing through regions with foreground galaxies. Thus there is a greater red shift for the light going through regions with foreground galaxies, and this accounts for the different values found for the Hubble constant.

Vigier also cites additional evidence for nonvelocity red shifts. For example, if the light from stars is measured when passing near the sun, it displays a higher red shift than when measured in a different area of the sky. Such measurements can be made only during total eclipses of the sun, when stars near the solar disc become visible in the darkness.

In short, Vigier explains the red shift in terms of a nonexpanding universe in which light behaves somewhat differently than it is normally supposed to behave. Vigier claims that his model fits the astronomical data better than the standard expanding-universe model, which cannot explain the widely different values obtained for the Hubble constant. According to Vigier, nonvelocity red shifts may be a general feature of the universe. The universe could very well be static, and thus there would be no reason for the big bang theory.