The Uncertain Universe: How Science Discovers its Truths


Science explores the universe, and one of it’s main tenants isn’t to explain everything exactly. No, it’s to try to validate explanations (and ideas) through experiments, or to put in other words: any idea someone has devised to explain an event in our universe, that idea must be validated through experiment in order for it to be considered a scientific fact. This is perhaps the most basic definition of science, but as we shall soon see, science is a bit more complicated than this definition would lead us to believe. First let’s take a look at what our universe is actually like.

We live in a universe ruled by uncertainty on the tiniest scales. There’s a good reason for this, and part of that explanation is summed up in how the atom is structured. One of the most notable features of an atom is how much space it has. The center of it contains a small, densely packed nucleus, where protons and neutrons cluster tightly together. There’s a cloud of electrons in orbit around the nucleus. For all those who have taken or read about physics, one may already know about how plus (positive) charges attract minus (negative) charges. This is easily proven with magnets, where the north pole and south pole are opposite charges and thus attract one another. Now, protons and electrons are also opposite charges, and thus they do attract one another, but what is stopping them from being piled atop the nucleus?

Part of that is due to the uncertainty inherent within our universe. According to Quantum Mechanics, we cannot know both the position and the momentum of a particle. Richard Feynman has an excellent lecture about this very topic, and I’ll quote his explanation here:

Quantum mechanics has many aspects. In the first place, the idea that a particle has a definite location and a definite speed is no longer allowed; that is wrong. To give an example of how wrong classical physics is, there is a rule in quantum mechanics that says that one cannot know both where something is and how fast it is moving. The uncertainty of the momentum and the uncertainty of the position are complementary, and the product of the two is bounded by a small constant. We can write the law like this: ΔxΔp≥ℏ/2, but we shall explain it in more detail later. This rule is the explanation of a very mysterious paradox: if the atoms are made out of plus and minus charges, why don’t the minus charges simply sit on top of the plus charges (they attract each other) and get so close as to completely cancel them out? Why are atoms so big? Why is the nucleus at the center with the electrons around it? It was first thought that this was because the nucleus was so big; but no, the nucleus is very small. An atom has a diameter of about 10−8 cm. The nucleus has a diameter of about 10−13 cm. If we had an atom and wished to see the nucleus, we would have to magnify it until the whole atom was the size of a large room, and then the nucleus would be a bare speck which you could just about make out with the eye, but very nearly all the weight of the atom is in that infinitesimal nucleus. What keeps the electrons from simply falling in? This principle: If they were in the nucleus, we would know their position precisely, and the uncertainty principle would then require that they have a very large (but uncertain) momentum, i.e., a very large kinetic energy. With this energy they would break away from the nucleus. They make a compromise: they leave themselves a little room for this uncertainty and then jiggle with a certain amount of minimum motion in accordance with this rule. (Remember that when a crystal is cooled to absolute zero, we said that the atoms do not stop moving, they still jiggle. Why? If they stopped moving, we would know where they were and that they had zero motion, and that is against the uncertainty principle. We cannot know where they are and how fast they are moving, so they must be continually wiggling in there!)

The interesting part about this discussion is that experiments have validated the above numerous times. We literally cannot precisely know both position and momentum of any given particle at any given moment. This is why scientists often quip that no one truly understands Quantum Mechanics, because of this uncertainty principle and because of another interesting aspect of the theory: wave-particle duality, where light (and matter when examined on a tiny, tiny scale) are both particles and a wave simultaneously. Although we cannot ever precisely measure both position and momentum, what we can do is calculate the probability of the most likely event within the system we are examining, and then in experiments, validate if that calculation is correct the majority of the time or not.

What does this mean on a philosophical level?

For one thing, quantum mechanics shows how we cannot ever be absolutely precise. All experiments result in statistical findings, where the finding is an average of what happens. The important point here is that there is no knowing exactly what is going on, but we can determine to a high statistical probability what is going on. This is how scientists over time have been able to determine general laws about the universe. All of these laws have been validated through experiments that show that the majority of the time these laws are correct. Has there been experiments that disprove a general law of physics? Not necessarily. For example, the law of conservation of energy states that the total energy in a closed state cannot change, as in it’s conserved, and thus cannot just randomly disappear. If one calculates out the probability of a violation of the conservation of energy, the possibilities of that violation do exist, but they are statistically fairly tiny percentages. So it can be safe to assume that in our lifetimes, we probably won’t see a violation of the conservation of energy. Experiments thus far seem to validate that idea. (This is of course a simplification of the example, but a more detailed explanation is beyond the scope of this post.)

This bothers some people because they want everything to be cut and dried, either/or, black and white. Either we know it exactly or we don’t, but nature just isn’t like that. Nature is complex, convoluted, and full of wonderful surprises. There’s a lot of probable events that can happen, and are fairly likely to always happen, but there is also the remote possibility that other events could happen instead. All we can do is examine the data and extrapolate and refine theories with what we have available within that data. Scientists examine what they can observe and test, and that data provides a framework for which theories are developed.

It’s also nice to note that on a macro level — as in if we’re examining things on a large scale — the odd effects of quantum mechanics are fairly minuscule, and so we can predict events with very high probabilities. Science is never about trying to find the exact answer to everything. As Richard Feynman puts it so well, “The sole test of the validity of any idea is experiment.” So any idea that people have about the natural world needs to be validated by experiments and observations. Does someone’s idea align with what we actually see and experience within nature? If it doesn’t, well that idea is rather useless for explaining what is actually happening, and so the idea is thrown out and a new idea is examined in its stead. Through this long process of examining various ideas and validating them through experiments and observations, the general laws of physics has been developed. These laws, although they hold some degree of uncertainty, are still very good with predicting what is the most probable idea of what is happening within nature. These laws tend to be called laws because they have withstood many experiments and have been validated by the results of those experiments and observations. That validation shows that these explanations are the most probable and most accurate explanations we have for describing our universe. So although our universe is based upon uncertainty on its most minuscule level, that doesn’t mean we still can’t come to understand how things happen.

Science, as a tool, is a very useful tool and can help explain a lot of what we experience within our universe, but it also is a slow process. It takes time to go through the process of experiments in order to validate the ideas people put forth to explain nature. As much as our universe can be harbor uncertainty, we still can come to understand it through science. All the technological advances you see today — and if you’re reading this on your computer, that’s a good example of technological advance! — stems from research in science, where people have undergone the long process of validating ideas and determining explanations for how various parts of the universe work. This is also why breakthroughs in science often are surprises, where experiments sometimes finds something unexpected, and thus new ideas are born and then tested for their validity. As slow as this process can be, because of it, it’s lead to the technology and medical advances we have today.

It’s also why I truly think that science literacy is very much needed within our culture. Because of our reliance on technology, we need to understand the basics of science, how science works, how science progresses, how technology is developed, and so on and so forth. Why? Because if we want to be active citizens within our country, we need to be science literate so we can make sound decisions on policies about technology, science, and our futures. To be science literate doesn’t mean you need to run out and get a degree in physics or anything. What it does mean is an openness to learning about science and the various research being conducted, and learning a bit about the history of science and its impact on our society. There’s a lot of great books out there written specifically to help people understand science, technology, and how it all works without requiring you to get a degree or perform any complex mathematical calculations.

For those interested, I’ve provided a list of where to start if you want to learn more about all of this:

A Short History of Nearly Everything by Bill Bryson is a marvelously well written book that tackles the history of science in nearly all fields of science. It’s a fun read, and definitely great for learning more about the history of science.

A Strange Wilderness: The Lives of Great Mathematicians by Amir D. Aczel is another great history book that focuses more on mathematics, which is often crucial to many fields of science. This books details the lives of mathematicians throughout history, especially ones that made a huge impact within the fields of math and science. It’s a fun book with a vast and interesting cast of real people.

Any book by Michio Kaku. He has written numerous books about science and technology, and writes it in an easy to read and understand manner. There’s no need for any prior knowledge of science or math to read his books.

Daily Storyline of Science is a great series of blogs written by scientists in various fields. It also has a weekly roundup of interesting scientific articles in various fields: http://www.scilogs.com/

Astronomy Picture of the Day provides stunning photographs of our universe with a short explanation below it: http://apod.nasa.gov/apod/astropix.html

This website is all about exploring various topics within physics and news concerning the latest research: http://www.physics.org/

In regards to the History of Science, this website provides a comprehensive Bibliography of the many articles and books written about the history of science: http://www.hssonline.org/publications/current_bibliography.html

Science Daily provides news about the latest research in various fields of science: http://www.sciencedaily.com/

Phil Plait, an astronomer, maintains this excellent blog about science. He also does a great job of tackling bad psuedoscience and various myths about science: http://www.slate.com/blogs/bad_astronomy.html

An important aside:

For those who are wondering, the biggest difference between psuedoscience and actual science is that psuedoscience cannot be validated through experiments. For example: anti-vaccine proponents often use psuedoscience to try to make a claim that vaccines are bad, but when scientists tried to validate their ideas, the data proved their ideas to be wrong and unsubstantiated. Another example is with climate change. Some people may deny that global warming is happening or that the Artic ice is “rebounding,” but the truth is their claims cannot be validated by known data and what is actually being observed and tested. Artic ice is actually melting faster than expected, and as it melts, the darker ocean waters absorbs more energy from the Sun, which in turn warms the Artic waters and causes more ice melt. Again the data doesn’t validate the claims made by the climate change denialists, and thus their idea just doesn’t work for explaining what is actually being observed and tested within nature. This is another reason why being science literate is useful: it helps you weed through the bad claims and find the actual truth within debates.

If there is one thing science definitively teaches is that it’s always good to have a healthy dose of skepticism when regarding claims about how things work in our universe. Seek out experiments that attempted to validate the claims, and see if they did or didn’t. One study or experiment isn’t generally enough to validate any claim — numerous ones are often needed. The above links I provided are great places to start.

Our universe is a fantastic and beautiful place, and science is a great avenue for exploring and experiencing that beauty. I hope the above helps others understand how science works and how much fun it can be.

Categories: Physics, Science, WritingTags: , , , ,

3 comments

  1. “Because if we want to be active citizens within our country, we need to be science literate so we can make sound decisions on policies about technology, science, and our futures.”

    Wow a good reason no doubt. People don’t realize how important will be a good understanding of science from now on. Things will change like never before in this century.

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