The Big Bang – Common Misconceptions

Update: Due to the popularity of this post I’ve made a few changes. The first was to remove an undeveloped definition of “explosion” which excluded some events I had not previously considered. I also added a bit more information on the CMB and the WMAP results.

Update 2: Since a few people have commented regarding my strange headings in which I switched between stating the misconception and the correct representation, I have revised all the headings so that they all state the misconception.

Recently, I’ve been hanging out on some message boards and realized that, just like with evolution, there’s a lot of really uneducated people that are being very vocal about their strawman version of the Big Bang. I began to notice that their entire argument was founded on these common misconceptions and thus, I figured it was about time to make a list of the really big ones and attempt to clear them up.

This is in no way a comprehensive list, nor is it meant to present all the evidence supporting the Big Bang, but instead, only to hit the highlights.

1) The Big Bang was an explosion
This seems to be a really big one. I’ve been told that I contradict myself because I point out that the Big Bang wasn’t an explosion so I obviously don’t know what I’m talking about. The term “Big Bang” was originally given to the theory (originally called “primeval atom”) by Fred Hoyle on a radio program in which he was mocking the theory. However, the misnomer stuck and has been causing confusion ever since.

Let’s first look at what the Big Bang theory really states: “Our universe began in a hot dense state which began, and still is expanding. In this initial event, all the matter in our universe was created with approximately 80% hydrogen and 20% helium.”

That’s my personal paraphrase, but after reviewing a great number of sources, it seems to be the most comprehensive one I can come up with. So let’s analyze it. You’ll notice that nowhere do we find the word “explosion.” Instead we find the term “expansion.”

The frequent picture people seem to have is matter flying outwards from a single point (like an explosion). However, the matter is all actually standing still while space itself expands dragging the matter with it.

The general analogy for this is having a series of paperclips on a rubber band. As the rubber band is stretched, the paperclips appear to move away from one another even though they are in fact holding still with regard to the rubber band. Similarly, galaxies hold still more or less (there are small movements due to gravitational interactions) while they are carried by the expanding universe.

So again, there was no “explosion” but instead, an expansion which is carrying all the rest of the universe away from us.

2) The Big Bang theory doesn’t explain what caused it

This is another big one I see a lot. If the Big Bang was the beginning, then what could have caused the Big Bang? You’ll notice my paraphrase above didn’t include anything about this. Pretty big hole eh?

Not really. The Big Bang theory doesn’t say anything about what caused it because, well, it doesn’t need to. Theories don’t try to explain everything, just what evidence is available and pertinent. Asking the Big Bang (and Evolution) to do more than this is a double standard. After all, the theory of Gravity doesn’t explain where mass came from. The Germ theory of disease transmission doesn’t explain where germs came from. Electro-magnetic theories don’t explain where charge comes from. Atomic theory doesn’t state where atoms come from.

So while it might seem like a piece of the puzzle is missing, as far as this single theory is concerned, it’s not really important. The origin of all these other pieces requires separate theories, with their own evidence, which are being worked on, but often times, are still in their infancy (ie, brane theory to explain the precursors to the Big Bang, Abiogenesis to explain the first life…)

Additionally, the Big Bang doesn’t go all the way back because it really can’t. As I pointed out earlier, when you start going back to far, things become fuzzy. The physical laws we’re all familiar with start to break down under such high energy densities. Really weird stuff starts to happen, like different fundamental forces ceasing to exist and merging with one another.

Thanks to work in particle accelerators, which can recreate such high energy densities for brief fractions of a second, we’re starting to get a feel for how physical laws operate under these conditions, and thus, are slowly working our way backwards. But there comes a point where we just don’t have a good enough handle on things to be able to say how things work back to pretty early (10^-35 seconds), but things were happening so fast and furiously, there’s still a long ways to go before we can uncover what happened to cause the whole mess.

Perhaps as better particle accelerators come on line, we’ll be able to work back even further, but this will require new theories about how matter and energy behave when shoved that close together, including a theory which has proved difficult for nearly a century, describing how gravity fits in with the other three fundamental forces into something known as the Grand Unified Theory (GUT).

3) There’s no evidence for the Big Bang

Sadly, yes, I have actually seen this one fairly often. I have no idea where people get the idea that scientists make things up without having good evidence behind it (oh wait… we’re out to disprove God because all scientists hate God or some crap like that).

The Big Bang theory does have a good amount of evidence behind it. So we’ll take a look at the three biggies.

a) Cosmological Redshift: As I explained in my earlier post, we can use spectroscopy to determine the rate at which galaxies are moving away from us. Additionally, since it takes light time to travel, the further away we look, the further back in time we are looking.

What we find, is that all galaxies in the universe are moving away from us. The further they are, the faster they’re moving away. So if we play the whole thing in reverse, all the galaxies will come back together at a single point in time. This point in time is what we call the Big Bang.

b) The Cosmic Microwave Background (CMB): Figuring that if you played everything back in time like this that all that energy would be crammed into a smaller space, that means the temperature would go up. And also since galaxies couldn’t have formed yet, we’d expect a gaseous sort of universe early on. As I discussed earlier, hot dense gasses emit photons at a peak wavelength corresponding to their temperature. Unfortunately, since things were so dense, photons couldn’t get very far.

However, with the available information, astronomers were able to determine at what density and time, photons would finally be able to get far enough that we could observe them. This is called the “surface of last scattering” and has a very specific temperature. So we should be able to look for photons with energy (wavelength) corresponding to that temperature.

But due to redshift, they will appear at a different wavelength. This radiation should appear from every direction. This was a prediction made by the Big Bang theory that was later confirmed by Penzias and Wilson who stumbled on it accidentally!

No other theory of the universe has ever been able to make such a profound prediction to the degree of accuracy the Big Bang did in this instance. Making such amazing predictions is one of the highlights of a good theory. None before or since have ever been able to pull off such a feat.

But the successes of the CMB prediction don’t stop there. Another important piece of the puzzle lies in that the CMB couldn’t be completely even. If it were, then galaxies couldn’t form since there would be no “seeds” with higher mass and thus a stronger gravitational pull to form around.

Thus, the Big Bang theory had to predict that the CMB would not be completely homogeneous. It should have some variations to it, and those variations would have to be of a specific size in order to get the universe we see today.

Early results for the Big Bang didn’t look too good for this prediction and threatened to sink the whole ship. However, the devices used were not actually sensitive enough to pick up these minute variations. But recently, with the Wilkinson Microwave Anisotropy Probe (WMAP), these perturbations have been discovered precisely as predicted.

Score two strong predictions for the Big Bang. Zero for any others.

c) Distribution of Elements: With the conceptual framework intact thanks to the first point, it was also possible to calculate how much of each element should be formed in the initial event. It should be obvious that, given a bunch of protons, electrons, and neutrons, hydrogen should be the easiest to form. Indeed, stick a proton and an electron in a room together and they’ll automatically hook up due to their magnetic attractions.

Additionally, with such high energies, it would be possible to fuse some of this hydrogen into helium and even a little bit of heavier elements. Since astronomers had a good handle on the energies, it was possible to calculate how much of each there should be. If that number didn’t match up with observations, the Big Bang theory would be shot.

Fortunately, the predictions do match up pretty closely. I stated a value earlier of 80% hydrogen, 20% helium, and neglected the rest since it would be statistically insignificant. In the universe today, we observe 75% hydrogen, 24% helium, and 1% everything else. This discrepancy is easily accounted for by nearly 14 billion years of stars cooking hydrogen into helium and other heavier elements.

So there’s three major pieces of evidence for the Big Bang, any one of which, if it had turned out any other way, would completely discredit the theory. Fortunately for the Big Bang, it has passed all of those tests, and not a single other theory has yet been able to adequately explain such things, or many anywhere near as profound of predictions (or any successful predictions for that matter). This is why the Big Bang stands alone as the premiere theory in cosmology today.

4) The Big Bang doesn’t leave room for God

This isn’t a scientific argument, but rather a philosophical one which is completely beside the point. However, since I see it used frequently, I’ll go ahead and address it.

The Big Bang, like all science, doesn’t have any implications either for or against God. What it may do, it place constraints on how God did things and these may run contrary to scripture. However, there’s two important questions here:

First off, is the scripture right in the first place? And, second, assuming it is, are you interpreting it correctly?

The first one is really beside the point given that it would be folly to approach such a topic, but the second is worth addressing. Many Christians have absolutely no problem interpreting scripture in a manner that’s completely compatible with scientific observations like the Big Bang and Evolution. In regards to the Big Bang, many people choose to interpret the “7 days” as a rather metaphorical statement in which days are better understood as “phases” and could have, in reality, been billions of years. Such people also note that Genesis’ account (roughly) follows the order in which science says things happened (although the order does differ on some points).

I think it’s also important to note that the Catholic Church has affirmed the Big Bang and finds no problem reconciling the theological and scientific perspectives on this point. Both Pope John Paul II and the Vatican’s official astronomer, George Coyne, have given strong support for the Big Bang theory. Additionally, the theory itself was originated by a Belgian priest named Georges Lemaître.

So we see, the Big Bang can fit well with scripture so long as one is willing to look at things from the right point of view.


I hope that clears up a few of the misconceptions people have been having, and I’m pretty sure that most people reading this blog were already familiar with all that, but perhaps this has given you a bit more detailed information that you can use next time someone throws out their strawman Big Bang.