American Scientific Affiliation

Astronomy/Cosmology Page


A History and Analysis of the 15.7 Light-Year Universe


Department of Natural Sciences 
Pinebrook Junior College 
Coopersburg, PA 18036 

 From: Perspectives on Science and Christian Faith 40.1:19-23 (3/1988)


 Objects in the universe are observed by virtue of the radiation they emit. On the basis of strongly supported theories dealing with the formation and propagation of radiation, astronomers have been able to determine distances from Earth to extremely remote segments of the universe.1 If one assumes that the radiation received from a distant object was generated by the object itself, and that the radiation traversed the distance between the object and Earth at a constant velocity, then the universe is at least as old as the radiation's travel time. Since radiation from some objects has taken billions of years to arrive, the universe is at least billions of years old. A common young-earth retort to the above astronomical argument for an extremely old universe is to claim that objects were created with their radiation e-n route to Earth. That is, both the object and the radiation en route to Earth. That is, both the object and the radiation appearing to emanate from it were created simultaneously.  Although distance measurements may be accurate, no correlation exists between distance and age. Hence the universe may seem billions of years old, but its actual age is only a few thousand years.

In a continuing effort by young-earth creationists to show the youth of the universe, another explanation has been promoted which allows material bodies to be located at great distances while the light-travel time from them remains quite short, on the order of 15.7 years. the ensuing discussion deals with the history and validity of this latter explanation.

Historical Background

Ever since the formulation of Einstein's second postulate of Special Relativity-that the velocity of light in a vacuum is independent of the motion of either the source or of the observer-many have attempted to give an alternate theory which retains so-called Galilean relativity.2 The difference between Einsteinian and Galilean relativity can be seen in the following example.

Suppose an airplane is moving with a speed of 1000 ft/see and that it fires its machine guns in the forward direction. Suppose further that the bullets leave the gun with a speed of 2000 ft/sec. To an observer on the ground who is being attacked by the plane, the bullets would move at a speed of 2000 + 1000 = 3000 ft/see. (Needless to say, we have a very dedicated physicist on the ground who is more interested in the results of the experiment than in saving his or her life!)

 Now suppose that the plane is moving away from the observer and that its aft guns are firing bullets at the same speed as before. In this case, the bullets pass the observer with a speed of only 2000 - 1000 = 1000 ft/see. In short, Galilean relativity states that the relative velocity between moving objects is found by the algebraic addition of the velocity vectors of these objects. In the above example, all velocities are parallel, so the simple addition and subtraction of the speeds of the plane and of the bullets is permitted Einsteinian relativity, on the other hand, operates quite differently. Suppose now that the plane is moving at a very great speed, say one-half the speed of light, and that it shoots laser beams which travel at the speed of light in a vacuum (henceforth called the "normal speed of light"). As the plane attacks the observer on the ground, one would think that the laser beams would dash by the observer with a speed of one and one-half times the normal speed of light. On the contrary, ground measurements would show that the laser beams pass with a speed no more than the normal speed of  light. The same situation holds as the plane moves away from the observer. Again, the speed of the laser beams does not change. In fact, regardless of the motion of the plane, the laser beam speed would continue to be that of the normal speed of light, no more and no less. Simple addition in the Galilean sense does not work. This observed constancy of the velocity of light, regard- less of the motion of the source or of the observer, is a cornerstone of Einstein's Theory of Special Relativity.

Other intriguing predictions in Einsteinian relativity are: no material object can travel faster than the normal speed of light; material objects gain mass as they gain momentum; moving clocks run slower compared to non-moving clocks; and a stick moving parallel to its length becomes shorter. All of these effects, except the last one, have been experimentally verified; hence, in spite of strange effects, Einstein's theory has long been held as the proper formulation for explaining kinematic and electromagnetic phenomena. Nevertheless, since the consequences of his theory contradict every- day human experience, various efforts have been made to explain high speed physical phenomena without abolishing ordinary (i.e., Galilean) ideas of space and time.

The most serious contender to Einstein was Walter Ritz. In 1908, he argued for the constancy of the velocity of light with respect to the emitting sources An observer would then find that the velocity of light depends upon the relative velocity between his or herself and the source.3 Although Ritz's hypothesis was in keeping with Michelson and Morley's classic result4, later experiments raised serious questions about his proposal. In 1913, Willem de Sitter argued that Ritz's assumption would introduce spurious eccentricities in the observed orbits of binary stars.5 Visually, the system would appear more eccentric than allowed by the laws of mechanics. De Sitter's effect would arise because the light from the component of the binary system moving towards Earth would travel faster than light from the same component moving away from Earth. In effect, circular orbits would appear elliptical. But de Sitter noticed no such effects to an experimental accuracy of one part in five hundred.

In 1942, Peter Bergmann argued that the Ritz hypothesis would produce multiple star images in visual binaries.6 Again, no such effects were detected, and the negative results of the above observations were used as evidence against the Ritz hypothesis.

 Astronomers, however, do not use meter sticks to measure distances;
they use the radiation emitted by the objects.

In 1953, however, Parry Moon and Domina Spencer analyzed a number of visual binaries to see whether the phenomenon predicted by Bergmann would even be visible in the first place.7 They assumed the Ritz hypothesis8, but their computations showed that Bergmann's predicted multiple images for binaries would not, in fact, be observed. (They do not elaborate on de Sitter's prediction of spurious eccentricities, and they do not mention whether they reexamined his data or not.) Hence, they concluded that visual binaries proved absolutely nothing about the constancy of the velocity of light. In the same article, Moon and Spencer performed a similar analysis of spectroscopic binaries and of Cepheid variables.They concluded that the Ritz hypothesis would produce spurious spectral lines, but no such phenomenon was observed.

Moon and Spencer gave two possible explanations for the negative spectroscopic results: (a) the velocity of light is constant after all, in favor of Einstein, and the Ritz hypothesis is wrong; or (b) the velocity of light is constant with respect to the source, in favor of Ritz, but space is curved. In the latter case, although astronomical space is unchanged, the time for light to reach the earth is greatly reduced, thereby eliminating the time differential necessary to observe multiple spectral images. In their own words:

Assume that light travels in a Riemannian [i.e., curved] space. The usual distance ... employed by astronomers is unchanged as regards material bodies; but for light, it is replaced by the corresponding Riemannian distance .... In emnee, therefore, the method of this paper leaves astronomical space unchanged but reduces the time required for light to travel from a star to the earth.10

By appealing to their data, these authors fixed the radius of curvature of the universe at five light years. In  such a universe, light from the most distant objects would reach the Earth in only 15.7 years (one-half of the circumference of a five light year circle), thereby ensuring that the predicted effects of Bergmann (and de Sitter?) would not be seen.

Subsequent to Moon and Spencer, new life was breathed into the Ritz hypothesis by J.G. Fox (ref. 2). Fox argued as follows: The velocity of the radiation emitted by a source is not the critical factor. What really matters is its velocity after passing through a medium. If this medium is stationary, or moving very slowly with respect to the observer, then the velocity of the radiation is slowed down to the normal velocity of light. That is, even though the velocity of the radiation emitted by an object may initially differ, even greatly, from the normal velocity of light, passage of this radiation through a stationary medium of sufficient optical depth will destroy any evidence of the radiation's initial speed. (This is known as the Ewald and Oseen extinction effect.) Radiation will appear to travel at its normal speed regardless of its initial speed. And since binary stars and Cepheid variables are enveloped in gas which can "extinguish" the initial speed of the emitted radiation, no evidence can be deduced from the observations of de Sitter and Bergmann to disprove the Ritz hypothesis. Hence, even as late as the early 1960's, we were left with no direct proof, astronomical or otherwise, for the validity of Einstein's postulate on the constancy of the velocity of light. Does this imply that Mooin and Spencer were correct? Is the universe so small that light from its most distant parts takes only 15.7 years to arrive to earth?


Let us look at the difficulties with Moon and Spencer's formulation. First, Moon and Spencer, in effect, want to place the material bodies of the universe at a different location than what is inferred from the radiation they emit. Pay careful attention to their statement that "the usual distance ... employed by astronomers is unchanged as regards material bodies; but for light, it is replaced by the corresponding Riemannian distance. - - - "11 They would have a point if astronomers measured distances by laying meter sticks end-to-end from Earth to the object whose distance they are mea- suring, and then compared this result to that obtained by analyzing the radiation emitted by the object. A variation in these distance measurements could then be attributed to a difference in the path used by the radiation compared to the one in which the meter sticks were laid. Astronomers, however, do not use meter sticks to measure distances; they use the radiation emitted by the objects (ref. 1). Hence, the distance inferred by astronomers is precisely the light-travel distance, or  Moon and Spencer's so-called "Riemannian distance." One cannot speak of a "usual distance" as being different from a "Riemannian distance."12

Second, while the Moon and Spencer hypothesis explains the lack of multiple images in spectroscopic binaries and Cepheid variables, it introduces its own multiple images. A universe as small as they propose would be full of images resulting from the bending of radiation emitted from nearby sources. In effect, their hypothesis implies that objects which we observe are composed of nothing more than the overlapping reflections of a few nearby sources. Are we really to believe that the great Andromeda Galaxy, whose millions of individual stars can be resolved, is only a composite of multiple reflections of a few stars near Earth which happen to appear in the form of a spiral galaxy? The situation would be analogous to sitting in a barber's chair between two parallel mirrors that produce a series of images which fade into an apparent distance.

 Observations of both terrestrial and extra-terrestrial phenomena
 have shown once and for all that Ritz's hypothesis is invalid ....
Since Moon and Spencer based their hypothesis on Ritz, their proposal
should have been abandoned as early as 1964 and not used in discussions
on the age of the universe.

Third, with a Riemannian curvature of only five light years, objects farther than about 7.8 light years (circumference divided by four) would exhibit an increase in apparent size with distance.13 This means that a diffuse object, like a nebula, situated close to 15.7 light years away from Earth would fill almost the entire sky. It would be like looking at a curved mirror from its focal point: the reflection of one's eye would be seen covering the entire surface of the mirrort

Fourth, Akridge (ref. 5) has pointed out that a universe as small as the one proposed by Moon and Spencer, which contains the universe's present mass, would require a density which is totally unacceptable.

For all the above reasons, Moon and Spencer's solution should have been abandoned from its inception rather than touted as an answer to the astronomical age problem. But is Fox's criticism-that the observations of de Sitter and Bergmann did not take the Ewald and Oseen extinction effect into account-still valid? Definitely not, for by 1964 direct evidence for the validity of Einstein's postulate on the velocity of light was provided by a number of experimenters: D. Sadeh; T.A. Filippas and J.G. Fox; and T. Alvager et al.14 All of these experimenters measured the velocity of gamma rays which had been emitted by decaying subatomic particles moving at nearly the speed of light. In every case, the velocity of the gamma rays equaled that of the normal velocity of light in free space. In no case did the velocity of the gamma rays behave as proposed by Ritz.

In addition to the above Earth-based experiments, in 1977 K. Brecher used radiation from pulsars (rotating neutron stars which emit radiation in a periodic manner) to show that the speed of light was independent of the motion of the source.15 Neither Brecher's experiment nor the ones mentioned in the preceding paragraph were subject to Fox's criticism. Hence, observations of both terrestrial and extra-terrestrial phenomena have shown once and for all that Ritz's hypothesis is invalid. Similarly, since Moon and Spencer based their hypothesis on Ritz (ref. 8), their proposal should have been abandoned as early as 1964 and not used in discussions on the age of the universe. In the same manner, one must also reject any attempt to fix the universe's radius of curvature at the ridiculously low value proposed by Moon and Spencer.16

Young-Earth Reaction to Moon and Spencer

In spite of the inherent difficulties and contrary experimental evidence, numerous young-earth creationists seized upon the proposal of Moon and Spencer as an answer to the problem of light-travel time from distant objects in the universe. In 1961, Whitcomb and Morris commented that "the very fact that such a theory can be developed and seriously considered demonstrates that astronomy has nothing really definite (their emphasis] as yet to say about the age of the universe. 17 It is true that in 1961 there was no conclusive experimental evidence for the validity of the constancy of the speed of light; but it is unfortunate that these authors did not realize the intrinsic weaknesses of Moon and Spencer's proposal and reject it outright. In 1971, Harold Slusher accepted Moon and Spencer's results as being "in line with a number of physical indicators that the universe is quite young. "18 George Mulfinger, in his 1973 review article on astronomy, declared that "to the best of my knowledge this original paper [Moon and Spencer] has never been refuted."19 Ten years later, in 1983, Richard Niessen accepted the Moon and Spencer hypothesis as a possible harmonization of a young universe with the "allegedly great distances of the outer galaxies."20 Unfortunately, Niessen's proclamation was repeated by later authors.21 And as late as 1985, A.J. Monty White asserted that Moon and Spencer's view was the scientific explanation 1. most favoured by creationists. "22

And so it has gone. A proposal of dubious scientific value, later discredited by experiment, was uncritically accepted and promoted by numerous young-earth creationists as an answer to the problem of light-travel time from distant regions of the universe.

Ideas have always been debated in scientific circles. Some ideas remain and others are rejected when appropriate evidence is uncovered. It is a matter of integrity, however, that those who engage in the battle of ideas will have done a thorough literature search and that they will be knowledgeable in their evaluation of the evidence. But we find that the material written by some young-earth creationists concerning Moon and Spencer failed in thoroughness ---- crucial experiments were unknown or neglected-and in knowledge, as Moon and Spencer's idea was accepted in spite of its bad astronomy. On both counts, a trust that exists among scientists was violated. This not only affects the way in which non-Christians view "creation science," it also adversely affects the way they view the Gospel. If Christians cannot be trusted to be truthful and/or competent in the area of science, why should they be trusted when speaking about the validity of Christianity?

It is most unfortunate that the non-Christian world has been provided with yet another example of questionable scientific investigation by some young-earth creationists.


1. Any elementary astonomy text will discuss how astronomers measure distances by utilizing the radiation emitted by the objects whose distance is being measured. Also see David J. Krause's summary in "Astronomical Distances, the Speed of Light, and the Age of the Universe," Journal of the American Scientific Affiliation 33, (1981), pp. 235-9. A detailed explana- tion appears in Michael Rowen-Robinson, The Cosmological Distance Ladder: Distance and Time in the Universe (New York: Freeman, 1985). '

2 Histories of these attempts are found in W. Panofsky and M. Phillips, Clamimi Electricity and Magnetism (Reading, MA: Addison-Wesley, 1962), pp. 27244; W. Pauli, Theory of Relativity, tran& by G. Field (Oxford: Pergamon Press, 1958), pp. 1-9; J.G. Fox, "Evidence Against Emission Theories," American Journal Physics 33, (1965), pp. 1-17. %

3. See ref. 2. Ritzs original article appeared in Annales de Chimie et Physique 18, (19M), p. 145.

4 As an aside, D.C. Miller's apparent contradictory evidence to Michelson and Morley has been reanalyzed by R.S. Sbankland and found to be consistent with other observations which have reproduced Michelson and Morley's result. See D.C. Miller, "Observations with Sunlight on July 8-9, 1924," Proceedings of the National Academy of Sciences 11, (1925), p. 31 1; and R.S. Shankland et a]., Reviews of Modem Physics 27, (1955), p. 167.

5. Helpful explanations of effects caused by differing speeds of light emitted by the same source are given by Krause, ref. 1, p. 237, and by c. Russell Akridge, "The Universe is Bigger than 15.71 Light Years," Creation Research Society Quarterly 21, (1984), pp. 18-22, De Sitter's work appeared in Phokatische Zeitschtift 14, (1913), pp. 429, 1267.

6. Peter C. Bergmann, Introduction to the Theory of Relativity (New York: Prentice Hall, 1942). Also see the explanation by Akridge, ref. 5, p. 18

7. Perry Moon and Domina E. Spencer, "Binary Stars and the Velocity of Light," Journal of the Optical Society of America 43, (1953), pp. 635-41.

8. The Moon and Spencer hypothesis is intimately connected to Ritzs idea. On page 639 of their article, they refer favorably to Ritz three times. These authors support the Ritz idea because they see their view as "a simple and reasonable world picture that allows all of our ordinary ideas of local space and time to remain unchanged." (p. 641)

9. Spectroscopic binaries are binary stars which are too far away and/or in which the component stars are too close together to be seen visually. Spectroscopic binaries are detected by observing periodic Doppler shifts in the position of spectral lines as a result of the motion of each component. Cepheid variables are bright stars which vibrate (expand and contract) at a fixed rate that correlates with their intrinsic brightness. The vibration is inferred from the periodic change in the star's intensity, thereby allowing astronometers to find the distance to Cepheids by comparing their observed brightness to their intrinsic brightness.

10. Moon and Spencer, ref. 7, p. 639. :

11. Ibid.

12. How unfortunate that this fact was not grasped by Paul Steidi, who discusses Moon and Spencer in such a manner as to leave his readers believing the their proposal is viable, albeit "exotic." See The Earth, the Stars, and the Bible (Philadelphia: Presbyterian and Reformed Pub. Go., 1979), p. 224. Any explanation which places objects of the universe in "flat space" while having light travel in "Riemannian space" is completely untenable!

13. Martin Harwit, Astrophysical Concepts (New York: Wiley, 1973), p. 441; Steven Weinberg, Principles and Applications of the General Theory of Relativity (New York: Wiley, 1972), pp. 418-27.

14. D. Sadeh, "Experimental Evidence for Constancy of the Velocity of Gamma Rays, Using Annihilation in Flight," Physical Review Letters 10, (1963), pp. 271-73; T. A. Fihppas and J. G. Fox, "Velocity Of Gamma Rays from a Moving Source," Physical Review 135, (1964), pp. B1071-75; T. Alvager, F.J.M. Farley, J. Kjeliman, and 1. Wallin, "Test of the Second Postulate of Special Relativity in the GeV Region," Physks Letters 12, (1964), pp. 260-62. "

15. Kenneth Brecher, "is the Speed of Light Independent of the Velocity of the Source?", Physical Review Letters 39, (1978), pp. 1051-54.

16. Numerically, the present radius of curvature of the universe, in light years, is on the order of its age, in years. "

17. John C. Whitcomb and Henry M. Morris, The Genesis Flood (Philadelphia: Presbyterian and Reformed Pub. Co., 1961), p. 370. "

18. Harold Slusber, "A Scientist Explains," Science and Scripture (Mar/Apr, 1971), pp. 369-70. "

19. George Mulfingei-, Jr., "Reviews of Creationist Astronomy," Creation Research Society Quarterly 10, (1973), p. 174.

20. Richard Niessen, "Starlight and the Age of the Universe," Impact 121 (July 1983). Impact is a monthly publication of the Institute for Creation Research.

21. Frederic R. Howe, "The Age of the Earth: An Appraisal of Some Current Evangelical Positions (Part 2)," BiNiotheca Sacra (April/June, 1985), p. 119; Stephen R. Schrader, "Was the Earth Created a Few Thousand Years Ago?" in The Genesis Debate: Persistent Questions about Creation and the Flood, ed. by Ronald Youngblood (Nashville: Thomas Nelson, 1986), p. 67.

22. A.J. Monty White, How old is the Earth? (Welwyn, Herts., England: Evangelical Press, 1985), pp. 103--5.

23. For other examples of using outdated astronomical evidence to support a young universe, see my "Meteoritic Influx and the Age of the Earth," Journal of the American Scientific Affiliation 28, (1976), pp. 14-16. Reprinted in Origins and Change.- Selected Readings from the Journal of the American Scientific Affiliation, ed. by David Willis (Elgin, IL: American Scientific Affiliation, 1978). Also see Howard J. Van Till, "The Legend of the Shrinking Sun: A Case Study Comparing Professional Science and 'Creation-Science' in Action," Journal of the American Scientific Affiliation 38, (1986), pp. 164-174.