No, the distant starlight problem is not the same as the horizon problem

The featured image in the header of this post shows two colliding galaxies, formally known as NGC 4676, or more colloquially, as “The Mice.” It comes from NASA’s Astronomy Picture of the Day website.

They are about 300 million light years away, more than 100,000 light years across, and colliding with each other at somewhere in the region of 200 miles a second. The “tail” of the right hand galaxy is the result of tidal forces stretching it out across vast reaches of space as it collides with its partner. A quick back-of-the-envelope calculation tells you that that tail must have taken at least one hundred million years to get spread out like that.

Distant starlight is a massive problem for the young-earth timescale. Not only must light have taken billions of years to reach us from distant galaxies, but when it arrives, it shows clear evidence of processes that must have been going on for millions of years already. Astronomy PhD student Casper Hesp has a series of posts on the BioLogos website where he examines the evidence from distant starlight in considerable detail. Another example that he cites is relativistic galactic jets.

Artist’s impression of the Milky Way. The red circle represents a distance of six thousand light years from the sun; everything outside of it is the distant starlight problem.
Image source: Wikimedia Commons

On a related note, the oft heard YEC claim that galactic spiral arms could not persist for billions of years is not true. Spiral arms have been well understood since the 1960s to be waves of high densities of stars within a galaxy: a theory that has been confirmed by computer simulations showing them to be extremely stable. The Wikipedia article on density wave theory has some animations showing clearly how it works.

How can we see distant starlight in a young universe?

If you read the attempts by YEC organisations such as Answers in Genesis, the Institute for Creation Research, Creation Ministries International and others to address the problem of distant starlight, you’ll find that they all claim that standard Big Bang cosmology has exactly the same problem:

It’s interesting to note that big bangers have exactly the same problem. That is, the background radiation temperature is almost uniform, to one part in 100,000, at about 2.725 K, even when we look in the opposite directions of the cosmos. Since the big bang would predict hugely different temperatures, how did they become so even? Only if energy was transferred from hot parts to cold parts. However, there hasn’t been nearly enough time for this to occur even in the assumed time since the alleged big bang—see the instructive article Light-travel time: a problem for the big bang by Ph.D. astrophysicist Jason Lisle.

There are just two problems with this argument.

  1. It doesn’t answer the question.
  2. It isn’t true.

This problem, also known as the horizon problem, is indeed a real one. But it isn’t even remotely similar to the distant starlight problem. The only thing that the two have in common is the problem of light travel time. Beyond that, the differences are so massive that to call them “exactly the same” is absurd.

The first, most obvious difference is scale. The horizon problem concerns distances of billions of light years: the size of the visible universe. The distant starlight problem, on the other hand, concerns distances of just six thousand: a fraction of the size of our galaxy. That is a difference of six orders of magnitude. It is the difference in size between a mountain and a molehill.

The two involve completely different eras of cosmic history, and completely different laws of physics. The horizon problem only concerns the first 0.002% of the age of the universe (300,000 years). The distant starlight problem concerns the entire history of the universe almost right up to the present day. The horizon problem operates at scales where the laws of physics are not fully understood, and that lie at the very limits of what we can explore experimentally and what we can theorise about. By contrast, the distant starlight problem concerns laws of physics that are well established, far more readily accessible to astronomers, well within the capabilities of modern measurement, and mathematically far more straightforward.

Omphalos, oh omphalos

The other big difference between the distant starlight problem and the horizon problem is that the distant starlight problem requires the creation of evidence for a history of events that never happened. The horizon problem does not.

Young-earth astronomers have made several different attempts to solve the distant starlight problem. These include Barry Setterfield’s c-decay; Jason Lisle’s anisotropic synchrony convention; and Russell Humphreys’ white hole cosmology. All of these make predictions that are not observed in nature; some of them descend into absurdity; and none of them can account for features of the cosmos that show evidence of a lengthy history, such as galactic collisions and relativistic jets.

Now the horizon problem does have a possible solution in cosmic inflation, which proposes that in the first 10-32 seconds after the Big Bang, the universe went through a period of dramatic expansion. To be sure, inflation is a bit of a mind-bender, and it does sound a bit whacked out, but it is a valid solution to the Einstein field equations, and many (but not all) cosmologists believe it to be the correct one.

But even if inflation turns out to be wrong, the universe can be explained in terms of the Big Bang being very finely tuned. Many scientists find that a bit of an ad hoc explanation, but there’s nothing theologically objectionable about it, and in fact, it would be compelling evidence for design. But there is no false history involved, the universe remains the same age as it appears to be, and the integrity of the Creator is upheld.

A comparison between the distant starlight problem and the horizon problem.
Source: Casper Hesp, BioLogos.

The fact remains that, far from being the same as the horizon problem, the distant starlight problem is in a completely different league altogether. To claim that the two are the same, when they are separated by six orders of magnitude, is patently absurd. It simply doesn’t make sense.


On evolution

Most of what I’ve said on this blog has been about the age of the earth and dating methods, and I haven’t had much to say about evolution itself. This is partly because I’m not a biologist, but also because I’ve never been entirely sure exactly what position I should take on the matter.

I can fully understand why many Christians struggle with evolution. It’s very much become a hot potato in the culture wars, with New Atheists and mockers pitting it against the Bible, and Christians taking the bait and becoming creationists in response. It does also pose some theological questions, such as what to make of Adam and Eve and the Fall. Some Christians (myself included) believe that the two can be reconciled; others believe that they can not, and that we must therefore reject evolution.

I’m not going to tell you that you have to accept evolution, or to what extent. That’s for you to decide. But if you decide to reject it, whether in whole or in part, you still need to make sure your facts are straight about it. It’s also important to be able to articulate exactly which aspects of the theory you are rejecting and why.

Make sure you are critiquing what the theory of evolution actually says.

You will only make yourself look clueless and ignorant, and quite possibly dishonest, if you attempt to debunk a cartoon caricature of evolution that no real scientist actually teaches. Portraying it as being about cats turning into dogs, or asking why there are still apes if humans evolved from apes, or likening it to dropping a bunch of Scrabble tiles on a table and coming up with Shakespeare, will all prove nothing more nor less than that you haven’t a clue what you are talking about. The theory of evolution does not work like that.

This is not evolution.
(Image source: Answers in Genesis)

Make sure that you understand what is actually meant by “evolution” in the first place. The formal scientific definition of evolution (taken here from Wikipedia) is very precise and refers to a specific process: change in the heritable characteristics of biological populations over successive generations. Make sure in particular that you understand the concept of common ancestry, because that is what you have to debunk — not shape-shifting, ridiculous hybridisation, or birds crawling out of dinosaur skins as if they were the Slitheen from Doctor Who. BioLogos has a couple of videos (here and here) explaining how evolution works and clearing up a lot of these misconceptions.

A lot of confusion comes about because young-earth creationists use the word “evolution” in a much broader sense than the scientific definition, conflating the process itself with its overall results (molecules to man), the timescale involved, dating methods, and a whole raft of philosophical or theological considerations that they perceive to be associated with it. More informally, they often use the words “evolution” and “evolutionist” as a passive-aggressive umbrella term for anything and everything in science that they don’t agree with. You may hear, for example, about “evolutionist” models of how the earth’s magnetic field works, even though how the earth’s magnetic field works has nothing whatsoever to do with biological evolution. Sometimes they even use the words “evolution” and “atheism” interchangeably.

To be fair, there is a tendency on the “evolution” side of the debate to de-emphasise the broad sweep of history in the definition of evolution (the frequently used definition of “change in allele frequencies over time” is an example of this), while evolution is also sometimes cited as justification for various atheistic or humanistic philosophies. But to react by turning it into a derogatory term for vast swathes of unrelated science and philosophy just causes confusion and muddies the waters. If you’re doing this, stop it. Just stop.

Then there is this expression “neo-Darwinism.” I have no idea what that even means.

Be careful not to misrepresent the evidence.

Before you confidently say that “there is no evidence for evolution,” or “there are no transitional fossils,” please remember that your audience all has smartphones, and they can type “evidence for evolution” or “transitional fossils” into Google as you talk. Every hit that they get for these searches will be a hit to your credibility.

The fact remains that evolution is not “just a theory”; it is an evidence-based, scientific theory. You may wish to argue that the evidence has been misunderstood, and that other interpretations are possible, but to pretend that it doesn’t even exist when quite clearly it does will just make you look like you’re sticking your head in the sand.

Are there any good scientific arguments against evolution?

You’re not going to falsify evolution, in the mainstream scientific sense of the word, in its entirety. The basic processes — descent with modification, mutations, natural selection, and even speciation — are readily observed both in the laboratory and in the wild. Furthermore, the fossil record shows indisputable evidence that these processes have been going on for billions of years, while genetic evidence such as endogenous retroviruses at the very least give humans and animals the appearance of being related. Either this is another example of “appearance of age,” or else it represents real history. You decide.

The Intelligent Design community looks for limits on what evolution can explain. To this end, they have come up with a number of concepts such as irreducible complexity, which claims that certain structures such as the bacterial flagellum could not have come about through an evolutionary process. Not being a biologist, I can’t critique irreducible complexity in much detail, but I get the impression that they’re jumping the gun by declaring it to be a done deal. I would have thought that irreducible complexity would be extremely hard to prove, because it’s not sufficient to show that one specific evolutionary pathway is impossible; you have to show that no alternative evolutionary pathways are possible either.

It’s often claimed that evolution contradicts the Second Law of Thermodynamics, or that mutations can not produce new information. Unfortunately, these arguments are based on a fundamental misunderstanding of the concepts of entropy and information. Entropy is often illustrated in the popular press by comparing it to teenagers not tidying up their bedrooms, but this is a gross over-simplification that doesn’t accurately reflect what entropy actually is, how it works, or what it does and does not apply to. Simplifications such as this can be useful in illustrating broad general principles to the layman, but you should never try to argue a point against them because the complexities and nuances of the subject that they gloss over will almost certainly render your argument wrong. Some properties of entropy and information are actually quite counter-intuitive: for example, it turns out that Shannon information and entropy are one and the same thing. Consequently, the Second Law of Thermodynamics means that mutations should produce new information.

There may be some other approach yet to be discovered, of course. I personally believe that at the very least, evolution must have required some “coaxing” to get us to where we are today, and I don’t believe that it was an unguided, random process. But even if Intelligent Design does get proven, that won’t necessarily falsify common ancestry, and it certainly won’t take us back to six thousand years.

In the end of the day, what you make of evolution is up to you. But whatever conclusion you come to in the end, it is important to be honest about it. Like everything else, make sure that you know what you are talking about, and that your facts are straight.

How much evidence is there?

Many debates about creation and evolution fail to appreciate the staggering amount of evidence that there is out there. Joel Duff, a Christian biology professor at the University of Akron in Ohio, has written about this on his blog, The Natural Historian, which examines the evidence from the fossil record in some detail, along with young-earth creationist responses to it. He points out, for example, that:

Estimates such as these are examples of Fermi problems. By coming up with some educated guesses (or known values) for the relevant quantities, we can then come up with an estimate for, say, the amount of kinetic energy in a hurricane. Overestimates and underestimates usually cancel each other out, and the end result will typically be well within an order of magnitude of the true figure.

How much radiometric data is there in the scientific literature?

It’s possible to estimate this value in a similar way.

First, how many geologists are there in the world? According to this blog post, about 500 geology students graduate in the USA every year. In China, on the other hand, there are probably about 40,000-50,000 geology students at any one time. This means that China must be graduating about 10,000-15,000 geologists every year.

I shall assume that the figures for the rest of the world per head of population are similar to those of the USA. Since the USA’s population is about 320 million and the rest of the world’s population is about 6 billion, this would suggest that about 10,000 further geology students graduate every year. Thus, there must be about 20,000-25,000 new geology graduates a year.

Now let’s assume that just one in ten of these graduates end up working as professional geologists, and that their average career length is about 40 years. This means that there would be about 80,000-100,000 geologists worldwide.

So how many radiometric dating results would they be churning out? In the first five years of his career, young-earth creationist geologist Andrew Snelling is listed on Wikipedia as having published an average of one paper per year in the scientific literature, most of them with one or two collaborators. Your average geologist is probably more productive than that, but I shall assume that this figure is fairly typical. I shall also assume that each publication in the literature contains an average of one radiometric result — some will contain more than one, but others will not contain any.

80,000 geologists, working in teams of an average of 2.5, publishing an average of one radiometric result per year, would mean about 32,000 new results per year. This means that in the last thirty to forty years or so, about a million new radiometric results could easily have been published.

Checking this estimate with Google Scholar

After writing the first draft of this post, it occurred to me that there is another way to estimate how much radiometric data there is in the literature: Google Scholar. We can do some simple searches for the most common radiometric dating techniques such as K-Ar, U-Pb, Rb-Sr, and so on.

A search for “K-Ar” (excluding citations and patents) returns about 360,000 results, with about 4,990 in 2016 alone. A search for “U-Pb” returns about 503,000 results, with about 11,200 in 2016. A search for “Rb-Sr” returns about 217,000 results, with about 6,170 in 2016. Even allowing for duplicates and false positives, it seems from these searches that my Fermi estimate came within a factor of two or so of the actual end result. It’s quite clear that we’re talking about hundreds of thousands of results, with tens of thousands of new ones being added every year.

Next time, we’ll ask a related question: how reliable are these hundreds of thousands of results?

What does oil exploration tell us about the age of the earth?

Is the scientific consensus on the age of the earth entirely the product of presupposition and an a priori commitment to uniformitarianism, evolution, and philosophical naturalism, as young-earth creationists claim?

We can be pretty sure that anything that comes from the oil industry won’t be for starters. Petroleum geologists have to come up with results that are correct, not results that are ideologically convenient. If they really were adjusting their geology to line up with their theology, they would send the oil companies on a wild goose chase drilling in all the wrong places, and wasting vast sums of money and a lot of political good will in the process.

So, what does the oil industry have to say about the age of the earth?

According to Answers in Genesis, nothing. A couple of years ago, Ken Ham wrote a blog post in which, among other things, he quoted Andrew Snelling, AiG’s resident geologist, as claiming that the ages of the rock strata are irrelevant to oil exploration:

Successful oil and mineral exploration and discoveries do not depend on believing the strata are millions of years old. In fact, the supposed ages are irrelevant, both to the exploration techniques used and to successful discoveries.

Jonathan Baker, a Christian geochronologist, responded to this claim on his blog, Age of Rocks. In a post titled “Can Young-Earth Creationists Find Oil?” he explained that anyone who has ever tried baking a cake should realise that Dr. Snelling’s claim is simply not true.

I know exactly what he’s talking about. My first attempt at baking a lemon drizzle cake was a disaster. I had the oven turned up too high, and as a result the outside of the cake ended up burnt to a cinder while the middle was still completely soggy and hadn’t even started. This was because the chemical reactions that take place when baking a cake are dependent on both time and temperature, so if the outside of your cake overheats while the inside is still warming up, you’ll end up with the same results as I did. In fact, chemical reaction rates are governed by an equation called the Arrhenius equation. For many common chemical reactions, the rate doubles for every 10°C increase in temperature.

As Dr. Baker points out, exactly the same thing is true for oil.

Lemon drizzle cake. Image courtesy of Daniel Hadley.

Once petroleum geologists have identified a location for a potential oil deposit, they need to determine not only how old it is, but also its thermal history. If it hasn’t been “baking” long enough, it will be “premature,” still solid, and impossible to get it out of the ground. On the other hand, if it has been “baking” for too long, or if the temperature’s been too high, it will be “post-mature.” At best you’ll get a lot of natural gas and much heavier, more viscous substances such as bitumen or asphalt, which are much more difficult to extract from the ground. At worst, you’ll find it all baked away into oblivion.

In other words, petroleum geologists have to get the ages of the oil deposits right. And they can’t afford to let their theology influence their geology either. There’s no room whatsoever for any kind of presupposition — atheistic or otherwise — in the oil industry.

I have not yet seen an adequate young-earth response to Dr. Baker’s post. Answers in Genesis does have an older article which attempts to poke holes in the conventional explanation for the origin of oil, and to come up with a young-earth alternative, but the fact remains that the conventional, old-earth models have proven to be very successful in their ability to predict where oil deposits can be found. Young-earth models have not even attempted it.

The message from the oil industry about the age of the earth is clear. Long ages are not an atheist conspiracy, they are not based on presupposition, they are not a religion, they are not any kind of “compromise,” they are not an attempt to make time for evolution, and they do not depend on your worldview. They are the clear and unambiguous conclusion indicated by evidence that can not be interpreted any other way.