Hard Evidence That Supports the Big Bang
The Fresh Perspective Podcast - Episode 11
How’s it going everyone? I’m Nick and you are listening to the Fresh Perspective Podcast.
In this episode, we will look at five strong reasons that scientists have to accept the big bang as the most accurate model to explain the shape, expansion, and composition of our universe. What does the evidence actually show? Is the big bang really the best explanation for what we observe? We will get right to it, in just a moment.
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The word “theory” in science doesn’t mean “guess” or “hypothesis.” A Scientific Theory is a rigorously-tested model, system, or idea that can explain several observed phenomena at once. It is the highest form of Scientific Certainty, the best explanation in its field so far. A theory explains the facts, which are based on the best possible evidence.
The Big Bang, for me, is one of the most bizarre of the most prominent Scientific Theories. It seems too strange to be science-fiction, but also too outlandish to be scientific fact. Things like evolution by natural selection, thermodynamics, germ theory, and Newton’s laws of motion, once understood well enough, mesh very well with our every-day experience. But this is a moot point, isn’t it? The universe really doesn’t care about making things easy for us. It doesn’t have to be at-all intuitive. Science isn’t about what can be comfortably understood. Rather, it seeks to uncover the facts of nature, whatever they may be.
Many of its opponents describe the big bang theory as a type of conspiracy, drawn up by atheists to contest against a belief in a god. This is ironic to me because many fundamentalist creationists have claimed the prospect of a big bang as a “win” for their argument that the universe had a beginning, and was not merely eternally present. At the time of its conception, as is still the case for many theologians today, the big bang was seen as the smoking gun of creation, leaving egg on the face of all of the scientists who were more content with a static universe model.
But as I said, the universe itself really doesn’t care about our theological, epistemological, or philosophical debates. Real science has never been about scoring points for your ideological team. Real science happens when we take our beliefs, presumptions, and prejudices and stuff them in the sock drawer. Only then are we ready to see things as they really are. Of course, this is easier said than done. Even Albert Einstein, whose theory of general relativity predicted an unstable universe with a beginning, personally favored the static and eternal model for the universe. However, true to form, the scientific community has been confronted with strong empirical data and evidence and has shifted its position, now declaring the big bang theory to be the most accurate representation of the past and present state of the universe.
What pieces of evidence could possibly have swayed an entire world of cosmological experts? How could such a bizarre theory become so mainstream? Well, I’m glad you asked. Here are five examples of strong evidence that support the big bang:
1. The Hubble–Lemaître Law and Red-Shifted Galaxies
Let’s turn back to the early 1920s. The United States was becoming a world power, flappers danced the lindy-hop, and every astronomer understood that we were surrounded by stars and smudgy nebulae, bright clouds of space dust, found all over most of the universe, a universe that was generally understood to be filled, mostly, by the galaxy, the Milky Way.
In 1924, in an observatory in California, Edwin Hubble made two groundbreaking discoveries that would change our view of the cosmos forever.
First – He observed that those blotches and smudges in the night sky weren’t just dust clouds. You see, an astronomer and computing genius named Henrietta Leavitt had discovered that certain stars (known as Cepheid variable stars or “standard candles”) had a known absolute magnitude, allowing astronomers to calculate their distance. Hubble was able to find these stars in the blotchy nebulae around us, and found that they actually belonged to entirely different galaxies, millions of light-years away at the very least! Hubble had solid proof that ours was only one of many galaxies in the universe.
Second – Hubble noticed something strange when calculating the distance between us and other galaxies. They were all moving away from us. The light from these galaxies was all slightly red-shifted. In fact, the further away they were, the faster they were moving. These observations must have been puzzling. Luckily, a Belgian Catholic priest and physicist named Georges Lemaître (a man who is usually credited as the first proponent of the big bang) could explain what Hubble observed.
Lemaître was a fan of Einstein’s theory of general relativity. On that foundation, he was able to calculate that in the past, the universe must have been much smaller, only to have expanded. This would explain why Hubble and every single astronomer after him (with sufficiently powerful hardware) can detect that the galaxies are, in fact, still moving away from one another.
Today, we understand that what I just said is actually a little off. You see, the galaxies are not moving away from each other on their own. In fact, it is the space between them that is stretching out, like water currents moving two floating leaves away from one another. Perhaps the best metaphor for this comes from a simple demonstration you can perform at home. Take a new balloon and, with a marker, create dots all over it. They will appear to be close together. Now, when you slowly blow-up the balloon, take note on how each dot seems to fly away from its neighbors. This is a 2D surface that behaves similar to how the fabric of space-time is indeed stretching and warping between the galaxies of the universe.
But what is all this talk about red-shifting? The reason why this is such a big deal is because red-shifting is exactly what we would expect the light from distant stars to do if they were traveling through space-time that is indeed stretching. If you stretch-out light, it becomes red-shifted. If the universe was collapsing, like a deflating-balloon, then all of the light from distant galaxies would be blue-shifted.
The red-shifting of light waves is similar to the collapsing or stretching of soundwaves. We can hear this happen when a noisy ambulance flies past us.
You may remember talking about this “Doppler Effect” in science class. The pitch of the sound is warped based on our position relative to the ambulance, its speed, and its direction. Light behaves in a similar way.
Put simply, the first big form of evidence for the big bang is the red-shifting of galaxies, all of which are observably moving away from us. It then logically follows, that if we could look back in time, we would find that all of the stars and galaxies of the universe were closer together. The further back we go, the closer together they would be.
2. The Ratio of the Elements Found in the Universe
Sir. Fred Hoyle coined the term “Big Bang” as a derogatory term for Lemaître’s theory. They were rivals to one another. However, his theories and observations would later prove to support the Big Bang Theory! One major part of his argument comes from the periodic table you see in your chemistry textbooks. If you thought that every element on that table shows up in nature in roughly the same amounts, then you would be wrong. Oddly enough, the smaller elements vastly outnumber the elements further down the table. The drop-off is pretty dramatic. About 75% of all of the baryonic matter in the universe is just Hydrogen. About 23% is Helium. 2% is all that is left for the rest of the periodic table, but the pattern still continues. The lighter and smaller elements tend to outnumber the heavier ones in that same asymptote-like trend.
This pattern is exactly what would be expected for Stellar Nucleosynthesis, a process that is central to the Big Bang theory and inflation.
3. The Structure of the Cosmos Itself
The Hubble telescope was named after the astronomer, Edwin Hubble, and it was a break-through in humanity’s ability to see the universe. It orbits our planet, past the interference of our atmosphere, and could, therefore, give us the clearest pictures of the farthest objects we could see at the time. Its first pictures, sent to us in the early 1990s, could have torn the Big Bang Theory to pieces. After all, Einstein’s theory of General Relativity, as well as the Big Bang Theory, made some testable predictions about the shape, size, and distribution of matter throughout the cosmos. The space between galaxies, the size of galaxies, the spaces between stars in galaxies, the conditions surrounding the birth and death of distance stars, as well as the distribution of things like quasars and black holes, all needed to fit within the predictions of the Big Bang for it to survive.
Did they? They did in the 90s, and they still do today. Every observation made of the universe so far, from every telescope to every computer model, has not refuted or discredited the big bang theory. Granted, the theory has been adjusted as we have received more data. The addition of the dark-energy dominated era comes to mind, but we are a long way from being able to replace it.
4. The Discovery of the Higgs Field and Fundamental Particles
The Large Hadron Collider (LHC) is the world’s most powerful particle collider. Underground, near Geneva, Switzerland, lies this massive tunnel system built for one purpose: to smash! If I were a Marvel Comics writer, this is where I would have Bruce Banner work! But the things we find there, I think, are far more astonishing than the misadventures of the Incredible Hulk. When it comes to particle physics, reality really is stranger than fiction.
In particle colliders such as the LHC, our understanding of particle physics, quantum mechanics, and the Big Bang singularity itself, are constantly tested. You see, this is how scientists can claim to know anything about the first seconds of our universe. The possible conditions of the early universe are simulated and small bits of matter are accelerated to near the speed of light, only to be obliterated when smashing into one another. It is like we are smashing a clock or a treasure-chest open in order to see what is inside. From these experiments, subatomic matter, anti-matter, and hitherto unknown particles have been observed. Particles such as positrons, neutrinos, and the Higgs-boson were just ideas until they were actually seen in this lab or in other similar labs. When we break down the complex parts of the universe, its simpler ingredients are revealed. We can then speculate about what the conditions the early universe had to have been in order to produce what is observed today.
This is all to say that if literally ripping the pieces of the cosmos apart hasn’t yet disproved the Big Bang, I am not sure what will.
5. The Cosmic Microwave Background Radiation
I wanted to save what, in my opinion, is the most powerful form of evidence for the Big Bang for the end of my list. But let’s take a step back. If you were highly skeptical of this theory, you may make the argument that scientists are making a “self-fulfilled prophesy” when it comes to the CMBR. From one point of view, scientists predicted that the cosmic microwave background radiation should exist, and then they claim to have found it. Isn’t that what is going on here?
Such an argument would hold some water if it weren’t for a few of the details about how it was discovered. Also important to consider, is how it is still being found and researched by many teams all over the world, building upon decades of discovery.
The Cosmic Microwave Background Radiation was first predicted in 1948 by cosmologists Ralph Alpher, Robert Herman, and independently by Robert Dicke. They basically predicted that there would be a time in the early universe when it cooled down enough for stable atoms to form for the first time. This would make the universe transparent for the first time while also letting free a great deal of energy in the form of light. If that indeed happened, some of that light should still be traveling out in the distance, right? For about 15 years, this was all academic. Different teams from different schools were trying to scoop each other, each trying to be the first to find evidence for this ancient light. So who won? Well, a team of engineers working for a phone company, that’s who.
In 1964, Arno Penzias and Robert Woodrow Wilson were trying to solve a problem for AT&T. Before, their company had no problem converting sound waves to electrical signals. That is how conversations were transmitted over telephone lines for decades. But AT&T wanted to take things a step further. They wanted to take sound waves into a receiver, convert them into electrical signals through wire connected to a radio dish, convert the signals into radio waves, and then reverse the process to receive them again.
This was a great idea, except that it had one annoying problem. No matter how hard they tried, Penzias and Wilson could not account for a constant hissing and buzzing of extra static and noise that was being picked up by their state-of-the-art radio signal detection hardware. Was it coming from a far-away galaxy? Was it resonating from the core of the earth? Was it the result of military testing across the ocean? No matter where they pointed their radio dishes, this background interference cold be detected everywhere! They even spent years fine-tuning and cleaning off their equipment just to make sure that it wasn’t their hardware that was causing the problem. A weak background signal in the form of radio waves that came from every direction? Who could explain it!
Well, Ralph Alpher, Robert Herman, and Robert Dicke could explain it. Penzias and Wilson had just accidentally discovered the CMBR! Years later, this radiation was explored in greater detail and first mapped by the COBE and WMAP satellites. The images that these satellites produced gave us something like a shadow of the early universe. You may have seen a render of this information, looking like a blurry pink and blue oval. The data shows us a universe with all of its matter and energy spread-out evenly, except for slight clumps here and there that would become the first stars.
In fact, even today, every time you drift between the stations and channels in an old radio or television set, about 1% of the static you hear belongs to that background radiation.
This changed everything. This was literally a baby picture of our universe. It fit all of the other evidence we had perfectly, like the piece in the center of a puzzle. The Cosmic Background Radiation is predicted by the kind of fundamental particle interactions demonstrated by the Large Hadron Collider, it shows the expected structure of the early universe, giving us a “transitional fossil” from the big bang to today. It supports Stellar Nucleosynthesis and what we would predict of the elements present after the big bang. And it is in the form of radio-waves, red-shifted over time and the stretching of the cosmos, similar to what was observed by Hubble, decades ago.
That is all I have for you today, but the conversation continues across social media and in the comment sections below. Do you agree with today’s message? Am I mistaken about some detail? How can I better elaborate on this topic in the future? Feel free to share your perspective!
Written By Nicholas Burk, Executive Board Member © 2019 Free Thought Initiative