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The Light from Distant Stars, Part 1

One of the biggest problems for young-earth creationism (YEC) is the light from distant stars. Because light travels at a constant rate, if we can calculate the distance to another galaxy, we can determine how long its light has been traveling to reach us. The existence of galaxies whose light has traveled thirteen billion years would seem to be an insurmountable problem for YEC. Jason Lisle of Answers in Genesis, however, argues that this distant starlight is not evidence of an old universe, and that it is in fact rather a problem for the big bang theory.

In an article titiled Does Distant Starlight Prove the Universe Is Old?, Lisle challenges what he deems the unwarranted assumptions of cosmologists, and attempts to replace them with his own young-earth assumptions.

At today’s rate, it takes light (in a vacuum) about one year to cover a distance of 6 trillion miles. But has this always been so? If we incorrectly assume that the rate has always been today’s rate, we would end up estimating an age that is much older than the true age.

Note how Lisle casually drops the phrase "older than the true age" into the sentence. A young earth is not his conclusion, but his starting point. But even Lisle acknowledges that a variable speed of light is just not consistent with the observed universe.

However, the speed of light is not an “arbitrary” parameter. In other words, changing the speed of light would cause other things to change as well, such as the ratio of energy to mass in any system. Some people have argued that the speed of light can never have been much different than it is today because it is so connected to other constants of nature. In other words, life may not be possible if the speed of light were any different.

Lisle also questions what he calls the "rigidity of time". Using Einstein's discovery of gravitational time dilation as a starting point, Lisle argues that it is not impossible to see ancient light even if the universe is only 6000 years old.

Since time can flow at different rates from different points of view, events that would take a long time as measured by one person will take very little time as measured by another person. This also applies to distant starlight. Light that would take billions of years to reach earth (as measured by clocks in deep space) could reach earth in only thousands of years as measured by clocks on earth.

I don't really follow the mathematics behind this (and I suspect Lisle doesn't either) but it would be quite a coincidence if the light took billions of years to reach earth, but appeared (from earth's perspective) to have only taken 6000 years. And it still wouldn't explain why earth telescopes consistently measure the age of the universe at 13.7 billion years.

Finally, Lisle attacks the assumption of isotropic synchrony conventions. He starts this section with an analogy of an airplane flight across time zones.

If the plane left Kentucky at 4:00 p.m. local time, it would arrive in Colorado at 4:00 p.m. local time. Of course, an observer on the plane would experience two hours of travel. So, the trip takes two hours as measured by universal time. However, as long as the plane is traveling west (and providing it travels fast enough), it will always naturally arrive at the same time it left as measured in local time.

A two-hour return trip leaving Colorado at 4:00 p.m. would arrive at 8:00 p.m. in Kentucky. The flight time is isotropic—the same amount of time in each direction—but the departure and arrival times are anisotropic due to the differences in local time.

Lisle argues for a cosmic equivalent of time zones—an anisotropic synchrony convention. Lisle's argument is both complex and subtle, and it relies on one of the surprising implications of the laws of physics. According to Einstein's theory of special relativity (SR), space and time are not absolute. This results in some strange effects. Casper Hesp discusses some of these in a post for Biologos.

A common SR textbook problem concerns the question of trying to fit a 20 feet ladder in a 10 feet barn: “How fast do you have to run while holding the ladder so that there is a moment at which the ladder is fully contained in the barn?” There is an actual quantitative answer to this question based on something called Lorentz Contraction.

Hesp considers SR's implications for Lisle's anisotropic light synchrony. Suppose you were sending a beam of light to a friend who is very far away. Your friend has a mirror to reflect the light back to you. If you send the beam at 1:00 and receive it back at 3:00, then it took two hours to make the round trip. If your friend's clock is synchronized with yours, they should have seen the beam arrive at 2:00.

Now comes the trick. Instead, one can choose the synchronization of clocks in such a way that the clock of your friend reads 3:00PM at the moment of reflection. Since on your own clock, the light signal left at 1:00PM and came back at 3:00PM, it seems like the ray of light took two hours to arrive at your friend, but zero hours to come back. This means the measured one-way speed of light is two times slower in directions away from you and infinite in directions towards you. This is allowed within SR, since synchronization is essentially a matter of convention.

With this background, let's look at Lisle's argument.

Since God created the stars on Day 4, their light would leave the star on Day 4 and reach earth on Day 4 cosmic local time. Light from all galaxies would reach earth on Day 4 if we measure it according to cosmic local time. Someone might object that the light itself would experience billions of years (as the passenger on the plane experiences the two hour trip). However, according to Einstein’s relativity, light does not experience the passage of time, so the trip would be instantaneous.

In this way Lisle gets starlight that theoretically could have traveled any distance but still reached earth on the right day. But is this science, or sleight of hand? We'll look at the implications of Lisle's ideas in the next post.

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