Monday, February 11, 2008

The Speed of Light and the Age of the Universe

Many Christians believe that the Bible obligates them to believe in a universe that is only several thousand years old. Since the discoveries of science show it to be several billion years old, they consider this to be an example of conflict between the Bible and science. I disagree. I believe that the biblical text can easily accommodate a universe billions of years old, and in fact a universe of any finite age. I would only consider science to be in conflict with the Bible on this point if the former showed the universe to be infinitely old.

Some Christians who think the scientific claims contradict the Bible's seek to find loopholes in the arguments that supposedly demonstrate that the universe is billions of years old. I think their motives for this are very honorable: they are trying to be faithful to what they believe the Bible teaches. Nevertheless, this feeds into the claim that science and Christianity are at war with each other, and so we supposedly have to choose one or the other. It's also intellectually irresponsible. Such tactics could be used to criticize virtually any position. It's the stock and trade of conspiracy theories for example.

In this post, I'm going to defend what I think is the simplest scientific argument demonstrating the universe to be billions of years old: the travel time of light from distant objects.

Starlight travel time
While light travels very fast (about 186,000 miles or 300,000 kilometers per second), it still has to traverse the distance between an object and our eyes in order for us to see the object. Thus, when we observe things, we’re seeing them as they were when the light left or reflected off of them. This results in the paradox that we can never actually observe anything as it is in the present, but can only observe things as they were in the past. Since most of the things we look at in our everyday lives are nearby, this distance is traversed, for all practical purposes, instantaneously. But when we observe astronomical objects the distances are huge, and there is a lag between the time the light leaves the object we’re observing and the time that the light reaches our eyes. For example, when we look at the sun (which I try never to do), the light took about eight minutes to travel to us. Thus, we are directly observing the sun as it was eight minutes ago, but we can never observe it as it is in the present. When we look at Jupiter, the sunlight reflecting off of it took 40 to 60 minutes to reach us, depending on our respective positions, so we are directly observing Jupiter as it was about an hour ago.

When we look beyond our solar system, the distances become much more vast. The dog star (Sirius) is one of the closest and brightest stars in the sky. It’s about 8.6 light years away, which means that the light from it took 8.6 years -- about eight years and seven months -- to reach us. Thus, when we look at the dog star we are directly observing it as it was eight years and seven months ago. The Crab Nebula is about 6,000 light years away, so its light took 6,000 years to reach us. This means that today we are directly observing the Crab Nebula as it was 6,000 years ago in 4,000 BC.

But we can’t stop here. With regards to intergalactic distances, the Crab Nebula is ridiculously close to us. The Large Magellanic Cloud is a small galaxy that orbits our own (the Milky Way), and is about 160,000 light years away. In 1987, astronomers observed a supernova in the Large Magellanic Cloud. Since the light from this event took 160,000 years to reach us, these astronomers directly observed a supernova which took place 160,000 years ago. The Andromeda galaxy is the nearest full-size galaxy to us and can actually be seen with the naked eye under the right conditions. Since it’s about 2 million light years away, this means that we are directly observing it today as it was 2 million years ago. Astronomers regularly observe supernovae in galaxies millions and billions of light years away.

The incomprehensible vastness of space and the speed of light combine to form an argument demonstrating that the universe is ancient. In order for us to see an object, the light from it has to traverse the distance between the object and us at the speed of light. Since the light from objects literally billions of light years away can be seen, the universe must be billions of years old. In order to escape this argument we would have to either deny that the objects are really that distant, deny that the speed of light is constant, deny that time is constant, or deny that the light actually traverses the distance between the object and ourselves.

Reliable distances
In an attempt to argue the first of these, some have suggested that perhaps the methods of measuring these distances are faulty. But the distances of objects can be measured by several independent methods which all reveal similar results; therefore, these distances are very certain, and can’t just be dismissed (Ross 1, 161-2; Stoner, 61-2). Moreover, if these objects were close enough for their light to have reached us in just a few thousand years, it would create obvious problems. “If all stars really are near rather than distant, their faintness would indicate that many are tiny, much tinier than the minimum size necessary for stars to burn. If stars were not distant and yet large enough to burn, another problem would be evident: a ‘night’ sky as bright as day -- fine for angelic creatures, perhaps, but deadly for earthly ones and certainly not the condition of Earth’s sky” (Ross 1, 162). Besides which, to try to maintain that the huge number of stars and galaxies that we observe all occupy only the space of a few thousand light years on all sides of us would put them so close to each other that they would be constantly moving and colliding with each other because of the gravitational attraction between them, something we simply don’t see.

The constancy of the speed of light
The second option is to argue that the speed of light may not be constant. This was suggested several years ago by some young-earth proponents when they noticed that our methods for measuring the speed of light today allow us to do so with greater precision than the methods used a few hundred years ago. However, instead of recognizing this as a byproduct of our technology advancing, they interpreted this greater precision as evidence that the speed of light itself was changing (Norman and Setterfield).

The first thing to note in response is that, “When astronomers measure wavelength positions of certain spectral lines in a distant star or galaxy, they are determining the value of the fine-structure constant when the light left that star or galaxy. The fine-structure constant value depends inversely on the value of light’s velocity” (Ross 1, 164). In other words, when we observe light from a distant object, we can determine what the speed of light was when the light left that object. Since we observe stars and galaxies over ten billion light years away and all points between, we can determine what the speed of light has been ever since the light first left these objects. What we discover is that the speed of light has been completely consistent during this time, therefore it has been the same for the last ten billion-plus years.

Moreover the speed of light is directly related to the amount of mass and energy. In Einstein’s equation E = mc2, E stands for energy, m for mass, and c2 for the speed of light multiplied by itself. Any change in the value of c for a particular light source would entail a change in its mass and/or energy output (or luminosity) as well. But everywhere we look -- up to over ten billion light years away -- we observe these ratios in accordance with the same value for c as it is now.

In fact, the speed of light is one of the examples of how the universe has been fine-tuned for life. If it was ever faster or slower, even to a slight degree, biological life could not exist. For example, as just mentioned, it would radically alter the luminosity (and hence heat dispersion) of stars, including our sun, a characteristic that has to be extremely precise for life to survive (Ross 2, 152). Moreover, the speed of light has quite a bit to do with body chemistry. “Certain life-essential proteins depend upon incorporating copper and vanadium, and the process by which these elements are incorporated depends on the stability of light’s velocity” (Ross 1, 165). Both of these considerations lead to the conclusion that if the speed of light was different when the first human beings walked the earth, they would have died instantly upon being created. Thus the constancy of the speed of light is an incredible example of how the universe has been designed by an intelligent agent, but those who argue that it has changed do not have access to it (Ross 1, 163-6; Stoner, 62-76).

The constancy of time
Another attempt along these lines is to argue that time moves at different rates in different parts of the universe. Thus, while seven calendar days transpired in one place, several billion years transpired in another. As such, these positions are sometimes presented as reconciliatory between the old-earth and young-earth positions, since they attempt to argue that both sides are correct. It has been defended recently by two authors.

The first is Gerald Schroeder in his books Genesis and the Big Bang and The Science of God. Schroeder, an Orthodox Jew, argues that from the perspective of a being outside of the universe, it’s possible that only seven calendar days would have passed while billions of years transpired in the universe. My response to this is that Genesis 1:2 clearly defines the perspective, the standpoint from which the events are being described, as the surface of the earth, not outside the universe. In fact, it states this as God’s perspective: “and the Spirit of God was hovering over the waters.”

The position that most young-earth ministries have advocated is that of Russell Humphreys in his book Starlight and Time. In this view, there was once a giant ball of water two light-years in diameter which contained the entire mass of the universe. This water ball then collapsed on itself and formed a black hole, a gravity well from which even light cannot escape. After a few thousand years, this black hole “evaporated” into a white hole, “the aftermath of a black hole so collapsed that all its trapped energy begins to escape via quantum tunneling” (Ross 1, 167).

This white hole is the universe we know. We live in it. Humphreys speculates that, because of Einstein’s discovery that the passage of time is related to velocity and gravity, if the earth were at the center of the white hole, the gravitational effects would cause time to pass much more slowly there than it passes in other parts of it. Six calendar days may have transpired on Earth while billions of years transpired elsewhere in our white hole/universe (Humphreys 1). Specifically, Humphreys argues that our galaxy is at the center of the universe, and so the earth is just approximately at the center. As such, this model is galacto-centric or neo-geocentric.

The problems with this view are many and manifest. “Such a scenario violates nearly every law of physics God established for the cosmos” (Ross 1, 167). First of all, a ball of water two light-years in diameter is physically impossible. The pressure and temperature at its center would ignite nuclear fusion. Second, a black hole takes much, much longer to evaporate into a white hole than Humphreys’s view permits. Hugh Ross points out that the very smallest black hole that the laws of physics would allow would take 15 billion years to become a white hole. The very smallest black holes that have actually been detected (a few times larger than the sun) would take 1066 years to become white holes. Humphreys is arguing that a black hole the size of the entire universe became a white hole. It simply wouldn’t happen in a few thousand years (Ross 1, 167).

Third, black holes get their name because the gravitational forces within them are so powerful that even light cannot escape from them. A white hole has everything so crushed that the energy escapes via quantum tunnelling. Obviously, such gravitational forces would crush anything that existed anywhere within it, and especially anything at its center. This would obviously preclude the possibility of life, and it’s certainly not the situation we find ourselves in.

Fourth, the temporal distortion between the center of the white hole and the rest of it do not add up to the temporal distortion Humphreys is claiming for it. It does not yield a universe billions of years old and an Earth thousands of years old. It yields a universe and Earth both billions of years old, but the earth less so.

Fifth, we simply do not observe time passing at such massively accelerated rates in different parts of the universe. Everywhere we look we see events (such as supernovae, gamma-ray bursts, galaxy rotations, etc.) transpiring at about the same speed. There is the relationship between velocity and time that Einstein discovered, and this does result in the behavior of the most distant objects, which are moving away from us at the highest speed, appearing slightly slower than those nearby. But, as I say, it is slight. Not to mention the fact that in Humphreys’s view distant events would not appear slower but faster; up to a million times faster. We just do not see anything like this.

In support of his theory, Humphreys has argued that “quantized” redshifts show that the earth is at the center of the universe (Humphreys 2). Redshift refers to the wavelength of a light wave being elongated or stretched. This elongation means that the light wave’s frequency is shifted toward the red end of the spectrum. When we observe a light wave’s wavelength being stretched like this, it shows that the object the light wave is coming from is moving away from us; the more elongated the wavelength, the faster away from us it’s moving.

Quantized redshifts (or redshift periodicities) refer to the claim that redshift values are clumped together into groups, that galaxies in certain parts of the universe are all moving away from us at the same speed. Humphreys claims that this proves that all of these galaxies are rotating around our own galaxy.

Again, there are some major problems with this. First, it doesn’t even address the problems mentioned above, and so does not constitute a significant enough argument for Humphreys’s views. Merely being at the center of the universe does not demonstrate that the universe is an exploding white hole with all of the temporal distortions that Humphreys maintains.

Second, I don't understand how the claim that galaxies are moving away from us leads to the conclusion that they are all rotating around us. Indeed, it seems to me that if they are moving away from us, they are not rotating around us. When an object orbits another, it is sometimes closer, sometimes further from the object (unless its orbit is a perfect circle, and the object being orbited is at the exact center). When it is moving further from the object, it is indeed obliquely moving away from it. But that’s only half the picture: it will also move closer to the object during the second half of its orbit. Humphreys’s claim would require that nearly all of the galaxies just happen to be in that stage where they are moving away from the object (us) it is orbiting.

Third, there are other, much stronger scientific evidences that we are not at the center of the universe (Ross 1, 170). In fact it’s worse than this: there is no center of the universe. The universe is an expanding three-dimensional surface on a four-dimensional background. Just as no point on the surface of a sphere is in the middle of it -- just as no point on the surface of the earth is at the center of the earth -- so no point in the universe is at its center.

Finally, the hypothesis of quantized redshifts was very speculative when it was first suggested, was rejected by the consensus of astronomers, and has since been refuted. There is no such phenomenon (Ross 1, 170). Thus, while this view may look impressive because it’s somewhat technical, it just has no basis in fact (Ross 1, 166-70).

Another problem with the claim that the earth is at the center of the universe is that it plays into the science vs. religion metanarrative. We are told that, prior to Copernicus and Galileo, people thought the earth was the center of the universe because they thought that the Earth and its inhabitants must be the most important thing in it. When geocentrism was abandoned for heliocentrism, it demonstrated that humanity must not be as important as Christianity claims. Science is often viewed as progressively demonstrating the insignificance of human beings, and thus contradicting the Christian worldview.

But this story falsely equates geocentrism with anthropocentrism. It assumes that since people thought human beings were at the center of the universe literally, they must have thought we were at the center metaphorically as well. But this is simply not the case. In fact, it was quite the opposite: in the medieval model, the closer you were to the center of the universe, the less significant and valuable, the less esteemed and privileged you were (Danielson 1 and 2). So while they thought the earth to be at the center of the universe, they thought hell was at the center of the earth, and Satan was at the center of hell. Rather than seeing the issue as heliocentrism vs. geocentrism, we should see it as heliocentrism vs. hell-ocentrism, or "diabolocentrism" (Lovejoy, 102).

Yet instead of pointing this out, some Christians have let the secularists dictate their own faith to them: today there are several Christian ministries (here's one) devoted to defending the proposition that the earth is at the center of the universe. And most young-earth ministries are actively promoting Humphreys’s neo-geocentric model in order to get around the problem of starlight travel time. In fact, Humphreys states explicitly that our location in the universe is directly related to how important we are to God, accepting the geocentrism = anthropocentrism equation (Humphreys 2, 102-3). But this is a revisionist history that opponents of Christianity invented in order to discredit it. I submit that we should not let those who deprecate our faith define it for us.

Traversing the distance
So if we can’t deny the vast distances between certain objects and ourselves, and we can’t deny the constancy of the speed of light or the progression of time, the only option left open is to challenge the idea that the light actually traverses the distance between the objects and ourselves. This has been suggested in two different ways, the first of which is the suggestion that light takes some kind of “shortcut” through space. One young-earth proponent argued this by noting the work of two scientists in the 1950s (Slusher, 33-7). These scientists tried to overthrow Einstein’s theory of relativity because it implies that there was a creation event and, hence, a Creator -- a conclusion they were loathe to accept. They came up with a bizarre hypothesis in which the light from distant galaxies would arrive on earth within a few years, and from two different directions. Unfortunately (at least for some), we don’t observe light arriving on earth from two different directions, and the fact that these two scientists were unable to support their theory mathematically, combined with the overwhelming amount of evidence in support of relativity that has become available since they wrote their article, completely repudiates their hypothesis (Ross 1, 166).

The second, and more common, way to argue that the light from distant objects does not actually traverse the distance between the objects and ourselves is the idea that God created the light “in transit” between us and the objects. That is, the light we observe didn’t actually come from the object itself, but is a beam of light God created in a line between us and the object.

This suggestion is an example of the claim that God may create things with a false “appearance of age”. Thus, it is claimed that God created trees with annual rings, polar ice sheets with annual layers, and coral atolls with daily band deposits for days, years, and millennia that never happened. This is a subject in and of itself, but the most obvious point to make against it is that it ascribes deception to God. This is obviously inconsistent with the Bible, which states 1) God cannot lie (Titus 1:2; Hebrews 6:18), and 2) he reveals himself through the universe he created (Psalm 19:1-4; Romans 1:18-20). To suggest that he made the universe in such a way that it looks differently than it actually is would contradict both of these claims.

To return to the case in point, starlight travel, let me just make a few points. First, when light travels through space, it passes through gas clouds, and this results in the light’s spectral lines being broadened, and the continuum (the radiation between spectral lines) becoming redder. The more gas clouds the light passes through, the greater this broadening and reddening will be. When we observe distant objects we observe these effects occurring in direct proportion to how far away the object is. So God wouldn’t have just created beams of light, but would have had to supernaturally alter their spectral lines to make it appear as if they had actually passed through a large number of gas clouds when they really hadn’t. Again, I don’t see how this wouldn’t be ascribing deception to God.

Second, when we observe light from distant objects, they don’t reveal the objects to be just sitting there, immobile. They reveal them to be moving, rotating, undergoing certain chemical and nuclear reactions, etc. In other words, we don’t just observe objects, we observe events. So again, God would be making it appear as if particular events were transpiring when they really weren’t. This can best be illustrated by dramatic events such as supernovae. Take for example the supernova in the Large Magellanic Cloud 160,000 light-years away mentioned earlier. If God created the light from this event in transit to appear as if it happened 160,000 years ago, and the universe is less than 160,000 years old, when did this event take place? The answer is, it didn’t. God would be, in effect, putting scenes in the sky which never really happened. This option is obviously incompatible with the claim that God is trustworthy, and reveals himself through his creation (Ross 1, 162-3; Stoner, 76-80).

Third, if we say God creates beams of light between objects and ourselves, we have opened a door we definitely do not want to go through. Most of our access to special revelation -- that is, reading the Bible -- is dependent on the properties of light. In order for us to see the letters on the page, light has to bounce off the page, and then traverse the very short distance between the page and our eyes. (Obviously, this isn’t the whole story, since the Holy Spirit illuminates the text for us by helping us to understand it. Of course, the Holy Spirit could just communicate to our minds directly all the time if he wanted to, but the fact that he had a few things written down suggests that he chose a more objective way as being more appropriate.)

But if God were creating beams of light between distant objects to make it appear that certain events were happening which really weren't, how do you know he isn't doing the same thing here? That is to say, maybe every time you try to read the Bible, God creates a beam of light (fiat lux!) between you and the page, and alters it to make it seem that the text says something it actually doesn't. If it's a real possibility that God would be doing this with distant objects, it's just as possible that he could be deceiving us about what the Bible says.

Obviously this is absurd. No one could seriously believe this, and especially not someone who believes that God is trustworthy. Indeed, this is a better description of the devil than God. But if God creates things with a false appearance of age, such a situation would be equally plausible. Since it's not, we know that God did not create the beams of light from distant objects in transit. Therefore, the light we observe from them actually traversed the distance between the objects and ourselves.

Therefore, since the light from objects billions of light-years away has traversed the distance between them and us at the speed of light, the universe must be billions of years old.

Works cited
Danielson 1 = Dennis Danielson, "Copernicus and the Tale of the Pale Blue Dot". Unpublished paper. Link.

Danielson 2 = Dennis Danielson, "The Great Copernican Cliché", in The American Journal of Physics 69/10 (2001): 1029-35.

Humphreys 1 = D. Russell Humphreys, Starlight and Time: Solving the Puzzle of Distant Starlight in a Young Universe (Green Forest, AR: Master Books, 1994).

Humphreys 2 = D. Russell Humphreys, "Our Galaxy is the Centre of the Universe, ‘Quantized’ Red Shifts Show", in TJ 16/2 (2002): 95-104. Link.

Lovejoy = Arthur Lovejoy, The Great Chain of Being: A Study of the History of an Idea (Cambridge, MA: Harvard Univ. Press, 1964).

Norman and Setterfield = Trevor Norman and Barry Setterfield, “The Atomic Constants, Light, and Time,” in Stanford Research Institute International, Technical Report (August, 1987). Link.

Ross 1 = Hugh Ross, A Matter of Days: Resolving a Creation Controversy (Colorado Springs: NavPress, 2004).

Ross 2 = Hugh Ross, The Creator and the Cosmos: How the Greatest Scientific Discoveries of the Century Reveal God, 3rd ed. (Colorado Springs: NavPress, 2001).

Gerald Schroeder, Genesis and the Big Bang: The Discovery Of Harmony Between Modern Science And The Bible (New York: Bantam, 1990).

Gerald Schroeder, The Science of God: The Convergence of Scientific and Biblical Wisdom (New York: Broadway, 1998).

Slusher = Harold Slusher, Age of the Cosmos (Santee, CA: Institute for Creation Research, 1980).

Stoner = Don Stoner, A New Look at an Old Earth: Resolving the Conflict Between the Bible and Science (Eugene, OR: Harvest House, 1997). Link.


Tyson said...

Hi Jim,

I preached on Hebrews 11 at my church two Sundays ago. I get the pulpit about once every two months. Anyway, I basically told folks that I didn't care about the age of the universe since the scripture says "By faith we believe that the universe was formed by God's command ... visible from invisible." That verse is where creationism begins and ends, for me.

I do think that God could make things appear old. It wouldn't bother me if I arrived in heaven and found that the case. But it would also seem odd if it turns out we really are descended from ape-like creatures, don't you think? I feel weird about both prospects.

Jim S. said...

Well you have to remember, the issue is not merely whether God could make things appear differently than they are, but whether he could do this and then tell us that these things are a true and clear revelation. Since his creation is revelation, he couldn't make it to look differently than it actually is without essentially being duplicitous.

Let me illustrate this. The Bible is a revelation from God. I know you don't think that God might tell you that there are some lies in the Bible -- not falsehoods that have creeped in through copying, or misinterpretations on our part, but actual lies that God inspired. Why not? Why do you think God wouldn't do this? Because the Bible purports to be revelation from God, and God tells the truth. If there are mistakes, it's on our part, not God's.

Similarly, God's creation is reliable and trustworthy revelation. As such, God did not create it to look differently than it actually is -- to trick us, essentially. He created it so that it cries out that it comes from his hand. That's why I reject the suggestion that God may have created the universe with a false "appearance of age". It's an attempt to muzzle God, and only let him speak to us in ways we have pre-ordained.

As for evolution, I'm not sure whether being descended from ape-like creatures is odder than having been created from the dust of the earth. If God wasn't weird, I'd suspect we were making him up.