With apologies to Inigo Montoya, you killed the word theory; prepare to die.
Heh heh, okay, a little more seriously, let’s talk about the word theory and what it means in science. You often see the word bandied about in discussions, with the inevitable “that’s just a theory” thrown in to try to cut off further discussion. Generally speaking, the person throwing that little hand grenade into the conversation is doing so incorrectly. Not very sportsmanlike.
As you’re no doubt aware, the word “theory” has multiple meanings. The common, popular meaning is a statement that is not backed up by sufficient proof. People deride another’s arguments by throwing the word “theory” around to describe someone’s hunch. Unfortunately, this is exactly opposite the meaning of theory in a scientific context.
A theory in the context of science is a comprehensive explanation of some part of the natural world that is supported by a large amount of data and evidence. So, no, not a hunch; not even close. “Natural world” goes beyond the earth to include the rest of the universe. Many theories not only explain what can be observed in the natural world, but also make predictions as to what else can be observed.
The Scientific Method
To better understand what a theory is, we first have to understand the scientific method (SM). The SM is the best way we know of to understand the workings of the world. (And again, “the world” means the universe, as well.) The SM has a number of steps:
- Make an observation.
- Conduct research.
- Form hypothesis.
- Test hypothesis.
- Record data.
- Draw conclusion.
So, let’s start with the first one – you see something in the world that intrigues you. Why is this like this? How does it work? It could be, “Why do baby animals look like their parents?” (theory of genetics), or “Why does Spain and the rest of Western Europe look like it fits in neatly with the Caribbean and the eastern shore of the United States?” (theory of plate tectonics). It could be anything. Maybe you have a deep and abiding interest in pain. Whatever interests you.
You research the subject more – do baby animals really look like their parents, or was I just undergoing a confirmation bias there? Does Spain really fit into the Gulf of Mexico?
You come up with a hypothesis: a statement that is a proposed explanation for a system, which forms the basis for further investigation and experiment. For example, baby animals look like their parents because both groups carry the same sets of instructions for how to construct themselves; Spain fits into the Gulf of Mexico because they used to actually be right next to each other, and now they’ve slowly drifted apart over many millions of years. Kind of like an old married couple where one’s a miracle worker and the other’s an old witch.
You figure out a way to test the hypothesis – a test that is repeatable by others. You record the data to see if it confirms or negates your hypothesis. Lather, rinse, repeat – one test isn’t enough. You figure out alternative ways of testing, ways that will poke holes in your hypothesis. If the data that you collect does not confirm your hypothesis, then the hypothesis has to be changed/reworked – the original can no longer stand. The data that you’ve collected can serve as the basis for a new, better hypothesis, but not the one you originally drew up.
Finally, after a long process of testing and collecting data, if your testing and collection is repeatable by others, and after a significant period of peer review by others in the field, where others are trying to poke holes in either your hypothesis, or your experiments, or your data collection procedures, then, and only then, does the hypothesis finally become a theory. That process takes many years, because not only does everything in this paragraph have to happen, but the scientific community as a whole has to come around to accept the new paradigm.
In terms of a negative example, in 1989, two chemists, Fleischmann and Pons, announced that they had discovered cold fusion. That is, the ability to obtain energy from a nuclear reaction at or near room temperature. However, their results – obtaining excess energy from a very simple setup – were not repeatable. Other scientists tried to replicate their results and failed. The result is that there is no “theory of cold fusion”.
Let’s look at a couple of different theories, shall we? Why yes, let’s! (heh heh)
Theory of General Relativity
Before Einstein proposed his theory of relativity, one of the problems that had developed using Newtonian principles of gravity was that Newton couldn’t explain the precession of Mercury’s perihelion. Y’know, because he was dead. Okay, he was mostly dead. If he were all dead, there’d be only one thing you could do: go through his clothes and look for loose change. But I digress. In its simplest terms, there was something weird about Mercury’s orbit that no amount of Newtonian physics could explain.
In more complicated terms, every time Mercury orbited the sun, it would not return to the same spot – the spot it reached moved slowly around the sun. Like this:
In 1915, Einstein proposed his Theory of General Relativity. Plato, Aristotle, Socrates? Morons. Einsteinian gravity not only explained the precession of Mercury’s perihelion (closest approach to the sun) neatly in his formulas, but the math also made a startling prediction. Because of the sun’s gravity, the stars nearest the sun during a total solar eclipse would appear out of the position in the sky from where they were supposed to be, due to the light coming from those stars being bent due to the sun’s enormous gravity.
So, here’s the beauty of an actual, scientific theory – either the math is right, or it’s wrong. Not much gray area. Yes, as discussed above, if it’s wrong, maybe you can go back and rework the math or the hypothesis to make it right, to cover the circumstance where it was wrong, while still covering all other circumstances. But as the theory stands, without the correction, it is wrong. A theory can therefore be disproven.
You probably know how the story turns out. Nothing could be done with regard to checking out Einstein’s prediction while World War I was raging. After the war, in 1919, a British astronomer, Arthur Eddington, took a bunch of astronomical equipment to the path of totality. During the eclipse, he took a photo of the sun, and more importantly, the star field surrounding the sun. The photo showed that the stars were out of position from where they were supposed to be, deflected by the sun’s gravity.
But what if the stars were not out of position? Humiliations galore. The theory would be proven wrong – instantly, and it would have been back to the drawing board for Einstein. Notably, Einstein actually was wrong with his Theory of General Relativity – he had made a mistake in his calculations. He had divided by 2 where he shouldn’t have, so that the predicted deflection was half of the actual deflection. He found the “divide by 2” and corrected the mistake – and the theory has held up to repeated tests ever since. (Einstein, while an absolute friggin’ genius, wasn’t quite as good when it came to actually doing those complicated equations. You know, the ones you’ve seen in movies that take up an entire blackboard.)
Big Bang Theory
Yeah, no, not the show with all the annoying characters. In the 1950s, there were two competing explanations for the origin of the universe. In the 1950s, astronomers knew from the work of Hubble in the 1920s (the dude, not the scope), that the universe was expanding.
One explanation for the state of the universe was the Big Bang hypothesis that we’re now all familiar with: that the universe originated with the explosion of a singularity, creating everything. Not only creating matter, but creating space and time as well. A singularity is a point of infinite density, much like a black hole. This explosion (expanded would be a more accurate term, but the visual image you get from the word exploded communicates the idea more effectively) caused the universe to rapidly expand outward from that singularity, continuing to expand today. The Big Bang hypothesis was put forward by a Roman Catholic priest and astronomer, Georges LeMaitre, in 1927.
One of the direct implications of the Big Bang hypothesis is that there is a beginning to not only space, but to time – there is, so to speak, a creation point, a time back beyond which you cannot go further. This was anathema to the other prevailing hypothesis at the time, the Steady State hypothesis. This was put forth primarily by a cosmologist named Fred Hoyle, its chief champion, in a paper in 1948. This model of the universe acknowledges that the universe is expanding, but states that as the universe expands, matter is continuously created in the space created. This means that a view of the universe in any direction would continue to look the same even though the expansion would have the tendency of thinning it out.
Back in the Fifties, there was no way to prove or disprove either competing model. However, the proponents of the Big Bang version were able to start with the expansion rate of the universe, which was known (it’s called the Hubble constant), work backwards from that to estimate the age of the universe, use incredible amounts of math to calculate the initial conditions of the universe, and then use those same amounts of math in reverse to calculate what the current conditions in the universe should now be. They’re so smart.
In other words, just after the singularity exploded, the universe was at a particular temperature – and an extremely high one, at that. Something like 10 to the 32nd power. That’s a 10 followed by 32 zeroes. Pretty hot. Much hotter than, say, the fire swamp. In the intervening billions of years, as the universe expanded to its current size, the universe cooled – that temperature inevitably dropped. Incredibly, with enough math and physics, that current temperature can be calculated, and that’s what they did. They came up with a current temperature of the universe of about 2.7 kelvin – that intergalactic space had a temperature of just 2.7 degrees above absolute zero. (EDIT – one of my 11 loyal readers has correctly pointed out that a kelvin is a unit itself, like a meter or a liter, and does not take the word degree with it. Thanks.)
Well, this is all well and good, but how are you going to measure that, to test that prediction? How are you going to take the temperature of intergalactic space? Without any proof, or any hope of getting any proof, it seemed like the Big Bang model would just have to languish.
Along came Arno Penzias and Robert Wilson, two researchers for Bell Labs. In the early Sixties, there was this background noise, this low hum, that you could hear on telephone calls. The very smart people at Bell Labs worked very hard to try to eliminate it, but try as they might, they couldn’t.
Penzias and Wilson thought that this hum might be coming in the form of some sort of radiation from a nearby source in space. So, in 1964, they used a special type of antenna, a horn antenna, to search for a source.
They pointed the antenna here; they pointed the antenna there; but wherever they pointed it, they still found this low hum. They thought that the hum might be caused because of pigeon droppings – pigeons had nested inside the horn. So they got up in there, and cleaned out the droppings, as well as “clearing out” the pigeons, much like a brute squad would do. Still, it hummed, no matter where in the sky they pointed the antenna.
What could this be, this universal hum coming from all directions? They consulted with some colleagues at nearby Princeton University. Based on the strength and frequency of the signal, and that it was coming equally from all directions, they figured out what it must be – the cosmic microwave background radiation, the fingerprint of the Big Bang. Because it has been so long since the Big Bang, the background radiation left over from it is very cold. It only shines in the microwave portion of the electromagnetic spectrum – giving us the cosmic microwave background radiation.
Further investigation, with the Wilkins Microwave Anisotropy Probe (WMAP), the Cosmic Background Explorer (COBE), and the Planck Satellite, has all confirmed this, leading to this heat map of the universe:
That map shows the Big Bang – or more accurately, the cosmic microwave background radiation left over from the Big Bang – showing that the universe is still radiating at about 2.7 degrees above absolute zero no matter where we look.
Incredibly, we now know that you can see the cosmic microwave background yourself. Remember when you were a kid, and you would switch the station to a channel that had no signal? So, let’s say there was a Channel 2 and a Channel 4, but no Channel 3. When you switched the channel to Channel 3, you’d get that static, that gray and white and black snow:
Yup, you can actually see the evidence for the Big Bang yourself, right on your TV.
This one is my bugaboo, the one that really chaps my ass. As you may know, there is a divergence between Einstein’s relativity theories and quantum theory. Einstein’s theories deal primarily with gravity, the large scale of the universe, while quantum theory deals with the minute, the microscopically small scale of the universe. As they stand now, they are both simultaneously correct, and they are both irreconcilable. Each theory works fine – better than fine, they work incredibly great! – in its own domain, but each completely break down in the other. Einstein’s equations break down at the small scale and are inapplicable, and the same is true with quantum theory at the large scale.
“String <cough>Theory<cough>” attempts to be a “theory of everything”, to reconcile the two incompatible realms into one grand unified theory (GUT) that works both at the small scale and the large scale. You could not ask for a more noble cause than that. And I don’t have the chops to be able to even begin to try to explain it. However, after well over 30 years of intensive research into it by many of the best and the brightest, it is no closer to being solved: there is no GUT as of yet. Some have estimated that we’re still about three Einsteins away from a GUT in terms of the fundamental breakthroughs needed in physics to get us there. As some have put it, “String Theory” is “not even wrong” – meaning, it is so far out there that it doesn’t even make any sense. It is not testable; therefore, it isn’t even science.
For example, some versions of “String Theory” require 10 dimensions to work; others require 26 dimensions. This is as opposed to the 4 dimensions we live in: the three spatial dimensions: length, width, and height; and the dimension of time. These extra dimensions are wholly and forever undetectable, meaning that any formulation of “String Theory” cannot ever possibly be disproven.
Then why is it called “String Theory“? Because it is pure mathematics. And in mathematics, as opposed to in science, a set of equations that form a body of research in some field is called a “theory”. Ugh. Gee, thanks, math.
The “not even wrong” formulation is not my own. Like I said, I couldn’t explain “string theory” if I had a gun to my head – or tell you why it’s wrong. Rather, it is from Peter Woit’s book of the same name, describing the research into “string theory” as being a colossal waste of time, energy, resources, and brain power. Delving deeper, the phrase originally comes from theoretical physicist Wolfgang Pauli in the 1930s: “That is not only not right; it is not even wrong.”
In any case, if you ask me, it should be called String Hypothesis. Nothing has been proven, because the entire framework, by definition, is unprovable, untestable. Inherent in “String Theory” is that we will never be able to detect these extra dimensions necessary to make it work. So the term “theory” is – or at least to my mind, should be – inapplicable.
Got all that? No? OK, let me explain. No, there is too much. Let me sum up:
Please don’t throw the word theory around in regular conversation like it means an unsupported hunch. It has a specific scientific meaning that we should use instead in relation to a large body of evidence that has been thoroughly tested and reviewed that comprehensively explains some natural phenomenon. If you must use a word for that kind of unsupported hunch, then be sure to use the word hypothesis instead. And when your mathematician friends start using the word theory, tell them to drink a nice tall glass of STFU.