The Speed of Light, the Dating of Rocks, and the Earth’s Strata

“How Old Is the Earth?” series (post #6)

What I’m going to do with this post is list three pieces of evidence that get offered up by physicists, scientists, and geologists in their attempts to prove that the earth is billions of years old and the universe is even older. Then I’m going to provide the counter explanations the young-earth-creationists use to explain how each piece of evidence can align with a universe and earth that is less than 10,000 years old. My goal here is simply to give you a small taste of how the ongoing “chess match” between these two groups plays itself out. Obviously, I’m not suggesting that these three pieces of evidence are the only ones the groups debate. The fact is, there are hundreds of pieces of such evidence. Again, I’m just trying to give you the gist of how the debating goes.

Evidence #1: The Speed of Light

Physicists tell us that light travels in a vacuum at a speed of 186,000 miles per second. In layman’s terms, that means it takes light one year to cover a distance of six trillion miles. You say, “Fine, but what does that have to do with estimating the age of the universe and the earth?”

I’ll explain by using starlight. If we can stand on the earth and see light that originates from stars, and if we can reasonably figure out how far those stars are from the earth, then we can possibly assume that the universe is at least as old as the time it takes for that light from those stars to reach the earth. Get it?

Okay, the most distant objects we are currently able to observe are quasars, and by doing the math we learn that the travel time for the light coming from these objects is more than 10 billion years. So, that means that the age of the universe must be at least 10 billion years, right? Actually, it must be even older than that because those quasars certainly aren’t the innermost extreme of the universe. This, you see, is how physicists think.

But how do young-earth-creationists respond to this evidence from the speed of light? First, many of them contend that God created the entire universe as fully mature and “in motion” right from the start. For example, God didn’t create Adam as a baby; He created him as a fully mature man. Also, He created the fruit trees of the garden of Eden as fully grown trees that bore ripe fruit right from the moment they were created. Summing things up, the Bible indicates that God created the universe and the earth with “age” already on it, even though it was freshly created.

Applying this idea to the universe, it would mean that any light from space was already well on its way to the earth from the moment the object from which the light emanates was created. Young-earth-creationists point out that proof of this can be found in the fact that God specifically said that He created the sun, the moon, and the stars on day four of the creation week to give light on the earth (Genesis 1:14-18). You see, if the light from the sun, the moon, and the stars didn’t actually reach earth on that fourth day, God would have been a liar.

A second explanation that young-earth-creationists offer to the evidence of the speed of light is this: Perhaps that speed hasn’t always been what it is now. The idea is that it’s possible that God greatly increased the speed of light in the early days of creation and then slowed it down sometime later. If this was the case, light from celestial objects could have traveled to the earth in a fraction of the time it would now take it to reach the earth.

Evidence #2: Radiometric dating

Scientists tell us that radioactive isotopes decay from an unstable to a stable form at measurable, fixed rates. These rates are based upon the amount of radiation each isotope gives off as it moves from unstable to stable. Therefore, if you know the specific kind of radioactive isotope found within a substance, you can backtrack the math and calculate the age of the substance.

So let’s talk about igneous and metamorphic rocks, for example. These are rocks which were once extremely hot and then cooled into solid rock. Basalt (a type of solidified lava) is a type of such rock. By measuring the amount of radiation within a basalt rock, you can presumably calculate how long it has been since that solid rock was in its previous liquid state and thus deduce the rock’s age. Such methods of dating have resulted in data that leads scientists to proclaim that the earth itself must be approximately 5 billion years old, with the universe being much older.

But how do the young-earth-creationists downplay the accuracy of such methods of dating? They do it by casting serious doubts upon three assumptions that must hold true for the methods to be reliable. Here’s a crash course in those assumptions.

First, it is assumed that the decay rate of the radioactive isotopes has never changed since the dawn of creation. Well, maybe it hasn’t, but then again maybe it has. And if it has, all the data is unreliable.

Second, it is assumed that no contamination took place throughout the entire process by which the rock transformed from liquid to solid. This is a major deal because any such contamination would heavily skew the results. But who’s to say that contamination didn’t take place? Even though scientists do their best to find uncontaminated specimens to study, perhaps there aren’t any such specimens.

Third, it is assumed that the original quantity of the radioactive isotopes in the rock’s original liquid state was zero and that the only such isotopes within the rock were formed there as the rock moved from liquid to solid. But the problem with this assumption is that it doesn’t always stand up to real-world testing. Specifically, the solidified rocks from volcanic eruptions and lava flows that are well known from relatively recent  history have been tested and found to be many thousands of years or even millions of years old. Clearly, using radiometric dating methods to date rocks and in so doing date the earth is highly suspect.

           Evidence #3: The  Earth’s Strata

Geologists tell us that the earth’s strata are layers of soil that are originally laid down as sediment and are changed into rock, over the course of much time, by pressure, heat, and chemical reactions. One layer is gradually laid down atop the previous layer as time progresses, and the end result is more or less a vertical stack of layers, with the oldest layer being the bottom one and the newest layer being the top one. In other words, the deeper you dig into the ground, the deeper you dig into the layers of earth history. At least that’s the general premise.

Stratigraphy is the study of the layers of the earth’s strata, and by engaging in such studies geologists have come to the conclusion that the layers of the earth’s strata were laid down progressively and systematically over the course of hundreds of millions of years. They reach this conclusion by using radiometric dating, carbon dating, and other such dating methods to date the age of the rocks found within each layer of strata. Incidentally, this is also one of the ways by which they date any fossils found within a layer.

But how do young-earth-creationists explain the earth’s strata in light of the fact that they believe the earth is less than 10,000 years old? They do it by asserting that the layers of the earth’s strata were not laid down slowly and gradually, but were instead laid down relatively quickly — within a year or so — as a byproduct of Noah’s flood. That flood, after all, was caused not just by rain but by “all the great fountains of the deep” being broken up (Genesis 7:11). This speaks of incredible seismic activity beneath the ocean floors. Consequently, the process set into motion by such seismic activity, as well as the subsequent “waters receding continually from the earth” (Genesis 8:3), could have left us with not only the planet’s stacked layers of strata but also the entire fossil record of animals killed by the flood.

One famous example that young-earth-creationists cite concerning the earth’s strata is known as The Great Unconformity in the Grand Canyon. Basically, this is a gap in the accepted timeline of the strata where two formations that were supposedly formed one billion years apart are nestled right atop one another. This unconformity showcases one of two things. One, either a billion years passed between the two formations and no sediment was laid down for that entire billion years (an option that seems unimaginable). Or, two, a short period of time passed between the forming of the two formations. You can guess which option us young-earth-creationists favor.

Well, as you can see from these three categories of examples, if you want to believe in a universe and an earth that are less than 10,000 years old, you have some Christian physicists, scientists, and geologists out there fighting for your cause. I don’t pretend to be such an expert, but I can certainly read what these experts write and take encouragement from their conclusions. That is what I do, and let me go on record as saying that I greatly appreciate the awesome work these men contribute in defense of the Bible and its account of God’s creation week. I only wish they didn’t have to fight so hard against a lost, unbelieving, academic world that wants nothing to do with God or His written word.

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