Distant Starlight and the Speed of Light
A synopsis by Jim Mendelson
How can light get to us from stars which are millions of light years away in a universe which the Bible claims is only thousands of years old?
Some stars are millions – even billions – of light-years away. Since a light-year is the distance traveled by light in one year, doesn’t this mean that the light we now receive from such a star has taken millions of years to get here?
In spite of all the Biblical and scientific evidences for a recent creation, this is a problem that must be squarely faced. There is currently no wholly satisfactory solution that is accepted by the majority of creation scientists, so a number of different proposals will be touched on here.
Faced with such a apparent conflict between the Creator’s eyewitness testimony and what seems like a very reasonable deduction from observation, the first thing to point out is one that is often overlooked. Namely, that we do not actually observe an old universe – we observe certain facts, but from these we can deduce an age only if we make certain assumptions (= starting beliefs). Even though they may seem reasonable, they are nevertheless beliefs, so we should look carefully at each of these assumptions in turn, remembering that great humility is in order. We do not have access to infinite knowledge – only God Himself does. The history of science shows that what is deemed certain in one generation may be totally overthrown by new information in the next. A certain story may seem to fit all the known facts. But that turns out to be only because we didn’t have access to all the facts – a totally new framework may be found that ties in not only all the previous facts, but the new ones as well. (Throughout recent history, we have frequently seen critics claim that “the Bible is wrong” in one area or the other because of what we were told was “assured knowledge,” yet when new evidence came to light, the Bible was shown to be right after all.)
The assumptions that are used in deducing great age from the observation of light from very distant stars are as follows:
Assumption 1 – The vast distances assigned to the stars are real.
The further out one goes, the more indirect do the measuring methods become. However, even if there were a large margin of error for the very distant stars, this is not really relevant, since a Biblical time frame would allow only around 6 to 10 thousand years. Even our own Milky Way galaxy is measured at around 100,000 light-years in diameter. The universe must be very large to accommodate the huge number of galaxies that are visible.
However, an interesting possibility has been presented by physicist Dr. Russell Humphreys, who points out that the real question is “how far away were the galaxies when the light started out on its trip to us?” The Bible indicated 15 times, using three separate Hebrew verbs, that God “stretched,” or “spread,” out the heavens (for instance, Isaiah 42:5, 45:12, 51:13; Jeremiah 10:12). Since these heavens were created before their occupants, the stars and planets (referred to as the “host of heaven”), this stretching presumably refers to the fabric of space itself. According to Dr. Humphreys, there exists a solution to Einstein’s gravitational field equations which may allow a very rapid expansion of space and thus all things in it. Dr. Humphreys theory raises the possibility that the universe inflated to its present size in less than 6000 years. Thus, the light began its journey when galaxies were much closer (and also much smaller and less energetic) than today. Such as expansion would involve all matter symmetrically, and would not be detectable by those “on the inside,” as it were. However, it could account for observed redshifts in the wavelengths of this stretched starlight.
Assumption 2 – We know for certain how light travels in deep space. To insist on this would seem rather presumptuous, particularly when one considers the many awesome discoveries of modern physics (and even the sometimes bizarre theorizing – wormholes, time travel, creation of quantum universes, curved space…) For instance, in 1953, Drs. Moon and Spencer, neither of them creationists, proposed that light from stars traveled along curved pathways in a mathematical framework known as Riemannian space. If this were the case, they argued, then light from the most distant stars would reach earth in substantially less than 20 years (remember, they were not trying to prove a recent creation or support the Bible.)
Such a proposal is obviously difficult to prove, but has been critiqued on observational grounds. In a paper in a creationist journal, V. Bounds argued that if this proposal were true, then one should see multiple images of all heavenly objects. To our knowledge, there has been no attempt yet to rebut this critique.
Assumption 3 – Light has always traveled at the same speed throughout the history of the universe.
Obviously, this assumption is impossible to prove, however reasonable it might seem at first. If light was faster in the past, then it would be possible for stars to be both very distant and very young. This could be achieved either by a direct change in light-speed at some time after creation, or by a yet-unknown physical principle which caused the light velocity to slow down to today’s value (by reaching an asymptotic level, not unknown for physical quantities). The light we now receive from distant stars, though now traveling at today’s speed, would have covered much greater distances in the earlier years after creation.
In this regard, it is interesting that a Russian Professor (Troitskii, an evolutionist) published a paper in the journal Astrophysics and Space Science in 1987 in which he claimed that the observations relevant to cosmology (such as the progressive redshift in starlight and the background radiation, both of which have been used as evidence for a Big Bang) were in fact better understood as having resulted from a change in c (the speed of light). He proposed that c began at a near-infinite value. Such a proposal could not now be directly tested, but could be assessed indirectly to see how consistent it is with present-day observations. Unfortunately, the Big Bang idea, although there is a growing chorus of critics, has such a powerful hold on the imagination of cosmologists that any alternative explanations for these phenomena do not attract much attention by investigators. Troitskii’s work is done within a 20-billion-year framework, but the main point of mentioning it is to draw attention to his claim that changing c does not violate any established physical principles.
Also interesting is a monograph published by creationists Norman and Setterfield in 1987. They have accumulated all the known measurements of c for the last 300 years, and claim that when tabulated, these show that c was not constant in this period, but still declining, seemingly tapering off to a constant level in about 1960. They cite a number of statistical tests which they claim deny the constancy of c in that time.
A radical proposal such as this raises an enormous number of questions and potential problems in many fields of science. Some of these have been satisfactorily answered by proponents of the hypothesis, some have not. Hopefully, future work will clarify matters further, although a paucity of funding for creation-oriented research could mean that it may take several decades. In the meantime, we would advise caution before accepting (or for that matter rejecting) this proposal prematurely.
Assumption 4 – The universe could not have been created “fully functioning,” with people on earth seeing stars with the light already arriving from the beginning. This assumes that God is not a God of infinite power, and so is the most presumptuous of all. Biblical creation by definition is a miracle, using processes which are not now in operation. God is not dependent on the physical laws which we observe in the present, since He instituted these Himself. To say that God could not have created a universe which was both large and very young is thus challenging the very nature of God as revealed in His word, not just challenging the fact of recent creation as revealed therein.
The fact that we cannot easily conceive “how” is a different matter altogether. For instance, it is easy to say that “God could have created the light-beam already in place.” True enough, but it raises a problem. Say we are watching a star in our telescope which is one million light years away, and we notice that it explodes. That means the light reaching us now is carrying the information recording this distant happening. Now trace this part of the light beam (call it “ex” for explosion) backwards in time along the path of the light beam. By the time you get back to the time of creation (6 to 10 thousand years ago) you have reached a point which is less than 1 percent of the distance to the star. This would mean that the “ex” part of the light-beam began its journey from here – and not from the star! Thus, the information recording this explosion had to be “built-in” to the light beam, so what we see as having happened to that star may never have happened at all. The idea that observation of things further than around 10,000 light-years away is not necessarily linked to physical reality would be unsettling from both a scientific and theological viewpoint.
Nevertheless, the universe was created a mature, fully functioning entity. The stars created on the fourth day were created for man – as “signs and seasons.” There is no reason to believe that Adam and Eve had to wait four years for the first stars to “switch on” (the nearest star is about four light-years away). Similarly, we do not see new stars “blinking on,” as if their light had finally reached the earth. The model mentioned earlier by Dr. Humphreys may give us a way of better understanding how light was originally created “on its way” and yet not have this problem of “built-in information.” In a sense, it may also effectively involve a change in (apparent) c (since as the stars recede rapidly, the light beam remains intact), though it would not predict that this would be detectable in historical measurements. We hope that sufficient discussion has already taken place to enable the reader to see that the apparent problem of having young age and great size of the universe has a number of possible solutions. Did light speed change? If so, did it become constant thousands of years ago or has it, indeed, been detected in historic times? Is the solution to be found in the “stretching” of space implied in the Scriptures? Perhaps a combination of these factors? Or was an altogether different method used during Creation Week to create a fully functioning, mature universe, a method which we will perhaps never be able to elucidate? Whatever the answer, faith in the revealed Word of the Creator is the only reasonable starting point for all such inquiry.
Excerpt from The Answers Book, by Ken Ham, Andrew Snelling and Carl Wieland, published by Master Books, 1992.
RECOMMENDED FOR FURTHER READING:
Starlight and Time, Solving the Puzzle of Distant Starlight in a Young Universe, by Dr. Russell Humphreys, Master Books, 1994
Author: adapted from The Answers Book with permission from Answers in Genesis
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