In the previous article, we introduced what is often called the distant starlight problem. Given the enormous distances to galaxies, and given the known speed of light, it seems that light would take billions of years to traverse such distances. Yet, the fact that we can see these galaxies suggests that the light has indeed traversed these distances. Hence, our observations of distant starlight are often taken as evidence that the universe is much older than the biblical timescale would allow. We previously discussed some of the proposed solutions and found that they do not stand up to scrutiny.
In this article we will continue to explore additional proposed solutions to distant starlight. Creation astronomers and physicists do not currently have a consensus position on the solution to this perceived problem. Some creationists are bothered by this fact, but it is the nature of science that we don’t know everything and therefore we make hypotheses to be tested. Furthermore, science advances only when multiple models are presented and then systematically eliminated on the basis of observations until only the most probable model remains. In this spirit, I will here present some of the positions held by creation scientists, along with the strengths and weaknesses of such proposals.
CDK
One of the earliest proposed solutions to the starlight problem involved the suggestion that the speed of light may have been much faster in the past. After all, our estimation of the amount of time light takes to traverse cosmic distances is based on its current speed (in vacuum) of 186,282.3974 miles per second, or one light year per year. Hence, it would take ten billion years to reach earth from a galaxy ten billion light years away.[1] But if the speed of light were much faster in the past, then perhaps it could have traversed most of that distance in only a few thousand years when light was much faster, only recently slowing to its current value. This model is known as cdk as a shorthand way of writing “c-decay” where c stands for the speed of light. So the proposal is that the speed of light has been decaying (slowing) since creation, or perhaps since the curse.
The main strengths of this model are twofold. First, it is very easy to understand. The computation of light needing ten billion years to traverse cosmic distances is based on the assumption that it has always traveled at the same speed we observe today. Clearly, if that speed were much faster in the past, then the time it takes to traverse such a distance would be drastically reduced. No knowledge of physics is needed to understand this. And so this answer could be very useful in apologetics – if it were true.
Second, the model rightly questions a uniformitarian assumption. Uniformitarianism is the belief that rates and conditions are generally the same over time. Secular geologists assume that large canyons take millions of years to form because they have assumed the annual erosion has been about the same over time. The creationist geologist rightly points out that such an assumption is false; we know from recorded history that a global flood occurred approximately four and half millennia ago. The runoff from such a flood would produce catastrophic erosion at rates far in excess of those observed today.
Likewise, secular age estimates obtained from radiometric dating are often vastly inflated because they assume that radioactive decay rates have not changed over time. However, the RATE research initiative found compelling evidence that such rates were orders of magnitude faster in the past. By falsely assuming that decay rates have always been as slow as they are today, the secular age estimates are inflated from the true age by a factor of millions.
Could the same be true of distant starlight? It is very reasonable to ask the question, “Has the speed of light always been as (relatively) slow as it is today? Could it have been much faster in the past?” Advocates of cdk have even argued that there is evidence from early estimates of the speed of light that c has dropped by a measurable amount in the last few centuries.
It was a neat idea. But there is extremely compelling evidence that cdk is not the right answer to distant starlight. Namely, there is compelling observational evidence that the speed of light in vacuum has not changed over time. Consider the following example.
There are some situations where we can actually observe the (tangential) speed of light in deep space, which according to the cdk proposal was emitted in the past, and we can confirm that it traveled at the same speed then as now. Consider SN1987A. Astronomers observed a supernova – an exploding star – in the year 1987 in the Large Magellanic Cloud at a distance of 168,000 light years. So, in the standard secular view, this event actually happened 168,000 years before the year 1987, and took that long to traverse the distance. According to cdk, the event actually happened less than 6000 years ago, but light was able to traverse the distance in 6000 years because the speed of light was at least 28 times faster when the supernova occurred (168,000 / 6000).
However, only a small fraction of the light from this explosion was directed toward the earth. Some light went off in other directions and reflected off of the surrounding gas which then redirected the light toward earth – a “light echo.” This light arrived after 1987 because it took time to go from the supernova to the surrounding gas. By measuring the distance between the supernova and the surrounding gas, and dividing by the time between the two events, we can compute the speed of light when the supernova happened. And we find it is consistent with the current value of c and is not 28 times faster. In fact, as astronomers continued to collect images of the echo over the years, and playing these images in sequence (see the figure) we can actually see the light traveling away from the supernova position at the current speed of light (c).
Second, since light is a wave, any change in its speed over time will result in a change in frequency. Frequency is the number of wave peaks that pass a threshold per unit time. An increase in the speed of light would therefore produce an increase in frequency; conversely, a decaying speed of light would produce a drop in frequency resulting in a redshift. The change in frequency would be proportional to the change in the speed of light. According the cdk model, light has been able to traverse a distance of 10 billion light-years in 6000 years, implying a change in the speed of light by a factor of over 1.67 million. Therefore, the light from the most distant galaxies would be redshifted by this factor. But this is not observed. Instead, the highest redshifts observed in the most distant galaxies is a factor of around 11. Such observations are wildly inconsistent with the cdk model.[2]
Third, the speed of light is very special and unlike other speeds. It essentially sets the relationship between space and time, the relative strengths of magnetic fields to electric fields, and the relationship between matter and energy. But our very existence depends on these things being essentially constant. The famous equation E=mc2, for example, shows that the amount of energy contained in a mass is proportional to that mass multiplied by the square of the speed of light. Therefore, if the speed of light changes, then either the mass or energy (or both) of everything in the universe must also change.
And since cdk requires the speed of light to change by a factor of over a million, this means the energy of everything in the universe would have to decrease by a trillion (the square of a million due to the c2 term), or the mass of everything would increase by the same amount. Either result would be catastrophic. Consider the earth’s orbit. If its orbital energy drops by a factor of a trillion, the earth would fall into the sun. Alternatively, if the mass of the earth and sun increase by a factor of a trillion, then the gravitational force between them would again cause the earth to fall into the sun. The same effect would happen with all planets in the universe.
So, these observations rule out cdk as a viable solution to the perceived distant starlight problem. But notice that these refutations require a basic knowledge of astronomy and physics, whereas the cdk proposal itself does not. This may explain why the idea is still attractive to some.
Gravitational Time Dilation
Another model was proposed by creation physicist Dr. Russ Humphreys. The model is explained in his 1994 book Starlight and Time. The proposal makes use of relativistic physics – the branch discovered by Albert Einstein. One of the strange consequences of relativistic physics that was predicted by Einstein and subsequently confirmed by experiments and observation is called gravitational time dilation. This is the fact that all physical processes are equally slowed in the presence of a gravitational field. For example, clocks tick slower on earth than they do in deep space because earth has gravity. The closer to the source of gravity, the slower clocks tick. Hence, clocks on mountain tops tick slightly faster than clocks at sea-level. The effect is very slight, but has been confirmed using atomic clocks.
The model advocated by Humphreys proposes that the solar system is near the center of the universe; that the number of galaxies in the universe is finite, forming a roughly spherical distribution with our solar system near the center of this distribution. (Note that this is not geocentrism – the belief that the earth is the stationary center of the solar system.) If the universe is indeed structured like this, then the solar system would be in a gravitational well. This doesn’t mean that we would feel any extra gravitational force. Rather, it means that it would take energy to pull objects near the solar system to the perimeter formed by the most distant galaxies, and conversely, objects in distant space would gain energy if they moved toward our solar system. As such, clocks on earth would tick slower than clocks in the distant universe.
Humphreys proposed that this effect would be so severe that the distant universe could age millions of years while only thousands of years elapsed on earth. Hence, light could indeed take vast ages to traverse cosmic distances, but earth would experience only a few thousand years during that time due to gravitational time dilation. This model is based on well-established physics, and was embraced by many creationists in the 1990s.
However, over time, difficulties with the model became apparent. First, it is based on an untested assumption: the model only works if the galaxies in the universe are indeed finite in number and distributed in a roughly spherical pattern centered around our solar system. There is currently no proof of this; however, neither is there evidence for the contrary.
More importantly, the model works qualitatively, but not quantitatively. That is, given the estimated mass of all the galaxies in the universe (including dark matter), the amount of time dilation experienced on earth relative to the distant universe is very small, not nearly enough to account for our ability to see distant starlight within the biblical timescale. So, for example, suppose that earth clocks are slowed by 2% relative to clocks in the most distant observed galaxies. Then light from a galaxy 10 billion light years away would take only 9.98 billion years to traverse that distance as measured by clocks on earth.[3] It does reduce the time from our perspective, but not nearly enough to solve the perceived starlight problem.
Secondly, if the gravitational time dilation were strong enough to slow the passage of time on earth by a sufficient amount to solve the starlight problem, it would produce observable effects. Not the least of these would be a universal blueshift. Since processes in galaxies at tremendous distance from earth would happen much faster than processes on earth, light from these galaxies would have a much higher frequency – millions of times higher. We would therefore observe a blueshift proportional to distance. This is not observed. In fact, we observe the opposite – a universal redshift.
So the gravitational time dilation model seems to be eliminated on the basis of both theoretical computations and observations. Even Humphreys has abandoned this model, along with a subsequent model. The last time I chatted with him, Dr. Humphreys was working on a third cosmological model. Although the original model did not pan out, it was a brilliant attempt and helped to advance study on this topic by including the effects of the physics of Einstein – an extremely important consideration.
Dasha
Dr. Danny Faulkner published a paper in which he proposed a potential solution to the distant starlight issue which he calls the Dasha model. You can read his initial paper on this topic in the Answers Research Journal here. The paper also briefly summarizes other proposed solutions to distant starlight and their relative strengths and weaknesses.
So, what is the Dasha proposal? Faulkner states, “As a part of God’s formative work, light from the astronomical bodies was miraculously made to ‘shoot’ its way to the earth at an abnormally accelerated rate in order to fulfill their function of serving to indicate signs, seasons, days, and years” (Faulkner 2013). So Faulkner suggests that the light from distant stars really does come from those stars, and was able to reach earth quickly because God made the light move at “an abnormally accelerated rate.” In other words, the light moved much faster then than it does now.
This sounds strikingly similar to the cdk model, in which the speed of light is proposed to have been much faster in the distant past. However, Faulkner is careful to distinguish his proposal from cdk. He states, “I emphasize that my proposal differs from cdk in that no physical mechanism is invoked, it is likely space itself that has rapidly moved, and that the speed of light since Creation Week has been what is today” (Faulkner 2013). So, rather than light moving through space at a much faster rate than today, it appears that Faulkner is suggesting that space itself is somehow moved at incredible speed, and the light is simply carried along without changing its speed through space (c).
Faulkner compares this rapid “shooting” of the light from the stars to the earth with the miraculous rapid growth of the first plants that God created on day 3. God commanded the earth to “sprout” plants bearing fruit, which they did by the end of the third day (Genesis 1:11-13). The Hebrew root word translated “spout” is “dasha” from which Faulkner derives the name of his proposal.
Faulkner is very clear that his proposal requires a miraculous act of God, something not observable in the present. Since this act allegedly happened during the creation week when God was doing all sorts of miraculous acts which He is not doing today (e.g. the creation of new kinds of animals and plants), we must concede that such an act is possible.
However, appealing to a past miraculous action which is not specifically recorded in Scripture, is of an unspecified mechanism, and which makes no specific predictions about present observations, is not likely to advance our thinking on the topic. There may indeed be validity to the comparison of God “shooting” the light from stars to earth with God “sprouting” the plants on day 3. But comparing one miracle with another doesn’t really explain either. Suppose I said, “I have a model to explain how Jesus rose from the dead.” As you eagerly await my explanation with due skepticism, I then say, “He did it the same way He raised Lazarus from the dead.” My answer may well be true, but have I really explained either miracle?
The fact that God both created and sustains His universe does not impede our ability to quantify some of the ways in which God acts; in fact, it enables such an ability. For example, Isaac Newton certainly believed that God was responsible for the motion of the planets. But this didn’t inhibit Newton from discovering the systematic way in which God caused such motion: namely, the laws of motion and gravity. Newton wasn’t satisfied to simply say, “God makes the planets move somehow.” On the contrary, Newton’s conviction in the orderliness of God motivated his discovery of the laws of motion and gravity which allow us to compute the positions of planets far into the unobserved future.
Likewise, Faulkner’s Dasha proposal, without giving a specific mechanism (even a miraculous one), seems to be equivalent to saying “God did it fast somehow.” While no biblical creationist would disagree, the proposal “God did it fast somehow” is not a model or a solution, but merely a restatement of the perceived problem. The closest Faulkner gets to an actual mechanism is to suppose that space itself was rapidly moved or stretched by God, thereby carrying the light along. This is an interesting and legitimate idea. But Faulkner does not then go on to explore what the consequences of such a mechanism would be, nor what observable effects would remain today in evidence of the sudden transition from the moving of space during day 4 of the creation week to its current state. The equations of general relativity describe exactly what happens when space itself is moving, and should still be useful even if the cause of that motion is miraculous rather than natural.[4] But until such calculations are done, Dasha cannot be considered a model since it provides no mechanism and makes no testable predictions.[5] However, the premise is interesting, and perhaps a model will be developed in time.
Looking Forward
During the creation week, God was doing things that He does not do today – speaking new things into existence. Then, God ceased His work of creation by the seventh day (Genesis 2:2). However, God continues to work today in sustaining that which He created (Hebrews 1:3, Colossians 1:17). Science is the study of the systematic way that God currently upholds His creation. As such, the tools of science allow us to discover the way God currently sustains His creation, but are very limited in their ability to discover the way in which God created since we do not have observational access to the past.
However, even during the creation week, God sustained that which He was creating. Therefore, some aspects of the creation week were natural (the same way God works today) and others were supernatural (unique and unlike the way God works today). Those aspects which are natural can be probed and discovered by science since they are still in effect today. However, those aspects of the creation week which were supernatural cannot readily be discovered by science today.
Under which category do we place the effect of distant starlight reaching earth? I suggest that it actually falls under the category of natural law. That is, even in the present it is possible for starlight from the most distant galaxy to reach earth in less than 24 hours, or even instantly. To understand this issue will require some discussion of the nature of space, and time, and the concept of simultaneous. More to come.
[1] For the sake of clarity, we will here neglect relativistic effects. This includes the multiple definitions of distance (co-moving, luminosity, etc.) that are convenient to use in the context of an expanding universe.
[2] The redshifts we observe are most commonly interpreted as being due to expansion of the universe since this also would produce a redshift proportional to distance. If instead, the redshift were due to a drop in the speed of light, then the speed of light would have been only 11 times faster when the light was emitted. In other words, this would allow us to see stars up to 66,000 light years away, but no farther. Yet, even the nearest galaxies are more distant than this.
[3] This is a light-travel-time distance.
[4] Andrew J. S. Hamiton & Jason P. Lisle (2008) “The river model of black holes” Am. J. Phys. 76 519-532
https://aapt.scitation.org/doi/10.1119/1.2830526
[5] Just to get the ball rolling on this front, one effect that I would expect if light were rapidly made to reach earth by the stretching or moving of the intervening space, is an enormous redshift. Light is a wave and therefore has a wavelength. This wavelength is determined by the source of the light, and in the case of stars is determined by their surface temperature. But if the space in which the beam of light exists is stretched, then necessarily the wavelength of the light is stretched, resulting in a redshift. The degree of redshift would be proportional to the stretching of space, which (in order to bring light from distant stars to earth within two days) would have to be a factor in excess of a trillion. But such an extreme redshift is not observed.