Why the Big Bang isn’t what you think it is
[Editors’ note: This is part of America’s space issue, commemorating the 50th anniversary of the Apollo 11 moon landing. Click here to find our other stories that are out of this world.]
What is the Big Bang? If you think it is something like an explosion that started the universe, then you would be in the same boat as most people. As far as I can tell (and I have done a lot of asking around because it is kind of my job as an astrophysicist who communicates to audiences in all sorts of venues and media), that is about as close to the most common public perception of the Big Bang as you can get.
If you do think of the Big Bang like that, I do not want you to take this personally, but just about every word in that description is dead wrong.
What is the Big Bang?
Why are there so many misconceptions about the Big Bang? There are likely several reasons, but the most likely culprit is simple cultural patterns. Many people grow up learning or hearing about this particular version of the theory and spend most of their lives not needing to fact-check it. And if they do, any reference is likely to be chock full of nearly-incomprehensible jargon, so the original notions stick.
I am highlighting the Big Bang because, to me, it perfectly encapsulates a breakdown in communication between scientists and the public.
The Big Bang is not a theory of the origins of the universe. I will say it again just to be clear: The Big Bang is not a theory of the origins of the universe. In fact, we have no scientific theory of the origins of the universe.
The Big Bang is not a theory of the origins of the universe.
The Big Bang is a model of the early history of the universe based on abundant observations. The simplest and most powerful observation was made in the 1920s and revealed that galaxies are, on average, flying away from us and from each other. So over time, the distance between galaxies grows larger. This means that in the past (and I am sure you can follow my logic here), the galaxies were closer together. And in the distant past, they were all really smooshed together. And in the extremely distant past, they were really, really smooshed together.
The general theme is that in the past, our universe was smaller and hotter and denser, and in the future, it will be larger and colder and less dense.
That is the Big Bang. Seriously, that is it. I mean, of course, there are a lot of details in that story to flesh out and a lot more observations to back up those details, but that is the Big Bang in a nutshell.
Ultimately, science is a story of evidence. Scientists build mathematical models based on our observations to describe and understand the natural world around us. This construct naturally places a barrier between science and the public (since science is performed in a rather unnatural language for most people), but that is still about as neutral an activity as you can get. Sometimes the scientific process may produce statements that are in conflict with personal beliefs. Even the more refined understanding of the Big Bang outlined above may cause you a little bit of internal friction. That is fine. Science will just keep on doing its thing.
There are many scientists with deeply held religious views, of all sorts of faiths. There are also a bunch of atheists running around in scientific circles. They all seem to be able to sleep soundly at night, and they all seem to have come to a personal reconciliation of their faith with their work. As best as I can tell, when it comes to the relationship between science and faith and any possible friction you might encounter, it’s nothing personal.