The Basic Structural Components of the Universe

A recent poll by the Pew Research Center shows that while the public has a generally positive opinion about science, there are areas in which the general public and scientists disagree. For instance, 87% of scientists but only 32% of the general population believe humans and other organisms evolved by natural means. 84% of scientists but only 49% of the general population believe that global warming is a consequence of human activity. 82% of scientists but only 69% of the general population believe that vaccinations of children should be required.

These differences can certainly have an effect. Former Playboy bunny, Jenny McCarthy has popularized the idea that mercury-containing thiomersal preservatives in vaccines has led to the increased incidence of autism. Numerous scientific studies show this not to be the case. For one thing, the incidence of autism continues to rise even though thiomersal is no longer used in vaccines. Despite the convincing evidence of science, the McCarthy’s protestations to the contrary have led many parents to the conclusion that it is best to withhold vaccines from their children. According to one estimate, this has resulted in over 46,000 cases of preventable illness and almost 200 preventable deaths. Considering that they have all involved young children at the beginning of their lives, this is a sad story indeed.

Who is to blame for things like this? One idea is that scientists and educators do a poor job of explaining their ideas to the general public and students. Another idea is that America is saturated with pure wackaloon bullshit from its very core to its outer fringes. I don’t see these hypotheses as being mutually exclusive. I suspect they are both correct.

I have been trying to get a business adventure off the ground and there have been a lot of unforeseen problems. That has kept me very busy and my mind has not been much on blogging. But things are beginning to settle down a bit. So I hope to resume a more regular science blogging schedule. I cannot prevent the wackaloons from spouting off their crap. I do not have the power or the moral right to do so. But I can do a little something by trying to explain scientific concepts to the best of my ability and challenging specific instances of scientific misrepresentations.

I want to resume my science blogging by try to present some of the basics of science as I see and practice it. I am a reductionist scientist. I like to take a “bottoms up” approach. I think that the best way to understand something is to have a good foundation of the principles that underlie that phenomenon. I am a biologist. But biology is not the foundation of science. Biology is based upon chemistry and chemistry is based on physics. Physics is the foundation of science.
Thus, I believe that a strong foundation in physics helps one develop a good scientific understanding of the universe. To get that strong foundation I want to ask the question … “What is the ultimate structural component of the universe?”

Let’s take an historical approach to the question. Early Greeks were the first to ask that question. The question was, of course, formed a bit differently. They did an Einstein-like thought experiment. Suppose you had a knife as sharp as a knife could possibly get. Suppose you take a piece of matter and cut it in half. Then you take one of those pieces and cut it in half. Suppose you keep doing that until there is nothing left for you to cut. What would you end up with?

Some argued that you would never “end up”. They were the mathematicians. To them you could go on forever cutting things into smaller and smaller pieces. Others, most notably the philosophers Democritus and Lucretius, believed that you would ultimately end up with a piece of matter that you could no longer bisect. This would be the ultimate ground of the universe. They called that piece of matter the atom.

There is beauty in that idea. If it were true then matter would be made of a single substance. You can’t get much more elegant than that, can you? But it had problems, even then. If matter is made up of a single substance, how do you get things as intricate as a snowflake and as amorphous as raindrop, or as organized as living bird and as simple as a rock? How could a single basic building block produce so many different forms with so many different properties?
In order to explain this people came up with the idea of “essences”. According to this paradigm, matter was made up of different proportions of four essences; earth, air, heat, and water. So instead of having a single atom, you essentially had 4.

The difference between a base metal like lead and valuable one like gold lay in its relative compositions of earth, air, heat, and water. If one could add or subtract the right amount of the 4 elements, lead could be converted into gold. Such a discovery seemed like a sure fire get-rich-quick scheme. Indeed, it spawned the field of alchemy.
As science progressed, it became obvious that the earth/air/heat/water idea would not work. Matter seemed more complicated than that. There were a large number of things did not seem to be able to be converted into anything else. And that included both lead and gold.

The Russian, Dmitri Mendeleev, showed that you could make some type of sense of these things if they were arranged in a pattern. That pattern is what is now called the Periodic Chart of Elements. Mendeleev’s periodic chart was by no means complete. There were numerous holes in it. Here is where Mendeleev’s genius showed through. He predicted that we would eventually fill those holes and what we would fill them with would have certain predictable properties. He was right!! As new elements were discovered they fit in the periodic chart exactly as Mendeleev had predicted.

That is always very satisfying. But there was a problem. It presented a very muddled picture. Where Democritus and Lucretius’ atom had the universe made of a single type of atom and the “essence” theory had 4, Mendeleev’s picture (if you look at a modern periodic chart) has the universe made of between 111 and 118 different types. That’s not particularly elegant.

Well science progresses. All of Mendeleev’s atoms showed properties of electromagnetism. Perhaps these atoms were not the ground of the universe. Perhaps they could be broken down into smaller substances yet … substances that carried electrical charge. Perhaps, … but then if that were the case, why could no one actually break them down?
Well, they already had … they just didn’t know it. The scientific piece of equipment that had done so was the cathode ray tube. The thing that would one day morph into television screens throughout the world.

Cathode ray tubes emit a beam of particles. These particles can be deflected by an electromagnetic field in such a way that suggests they have a negative charge to them. In 1896 British physicists, J. J. Thomson, John A. Townsend, and H. A. Wilson, made careful measurements on the charge needed to bend the cathode ray beam. By doing so they could estimate the mass of the particles in the beam and their charge. They found that the charge was about the same as that of the smallest ion known (the hydrogen ion) but the mass was over a thousand times less. This was way too small to be an atom itself. It was the first “subatomic” particle discovered. It was the electron.

So, if there were a negatively charged electron, there should be positively charged particles as well … right? Everybody thought so. And they even had a good idea about what it was. The smallest particle known to contain a positive charge was a hydrogen ion. Nothing smaller had ever been seen. Furthermore, its positive charge was equal in magnitude to the unitary negative charge carried by an electron. Thus, it seemed that a hydrogen ion was likely to be the elementary positive charged particle. But proving that was not easy. It was not until 1918 that Ernst Rutherford succeeded in doing so.

Rutherford worked with newly discovered radioactive compounds. When they spontaneously decayed they would shoot out an alpha particle. Rutherford invented a device to detect these particles. It was a scintillation detector which was a device filled with nitrogen gas. Whenever, an alpha particle hit a nitrogen molecule it would cause the nitrogen to fluoresce. Rutherford showed that during the fluorescence, there was an unmistakable signal of hydrogen ion present. Where did this hydrogen ion come from? The only place was from the nitrogen. Thus, within a nitrogen atom were hydrogen ions. Thus, Rutherford reasoned hydrogen ions were indeed the elementary positive charged particles. He called them “protons”.

So, the universe suddenly became a lot more elegant. No longer were there over a hundred types of elementary particles, there were only 2 … electrons, carriers of negative charges, and protons, carriers of positive charges.

Alas, there were problems. All seemed fine for hydrogen. It made sense. The atom being electrically neutral had a single electron and within its nucleus was a single proton. The calculated weight matched exactly as predicted. With electrons weighing so little, virtually all the mass of the hydrogen atom was in its proton. Thus, when the atom lost its electron and became a positively charged ion, all that was left was a proton. Great … right?

Well it was great for the hydrogen atom. The problem, however, lay with all the other elements. Every one of them were heavier than they were supposed to be. For example, oxygen has eight electrons and eight protons. So it should weigh the same as eight protons … right? Wrong! It weighs about the same as sixteen protons … twice as much as it by all rights should.

What was going on? The best people could come up with was that perhaps within the nucleus of an oxygen atom were eight more protons that had somehow combined with eight electrons to be electrically neutral. Was there a better answer?

Again the answer had been seen but not yet realized. It was well known that when radioactive elements emitted an alpha particle, if that alpha particle hit certain light elements (lithium, beryllium, and boron) a high energy radiation was produced. At first physicists thought that this was probably some type of strange gamma radiation. In 1932, James Chadwick showed that this radiation was particle-like, had about the same mass as a proton, and was electrically neutral. Thus, the third particle of matter had been discovered – the neutron.

We now know that most oxygen atoms have 8 electrons, 8 protons, and 8 neutrons. Neutrons solved the problem of the extra mass in atomic nuclei. It looked like a pretty satisfying picture of the universe. Matter was composed of three different types of particles, electrons, protons, and neutrons.

Well, not so fast. Cracks began to appear in the three particles of matter theory. Each day the earth is bombarded by numerous cosmic rays. These are very high energy particles that come smashing into our atmosphere. When they do that they can create subatomic particles. It had been noted that on rare occasions these events would be recorded on scintillation detects. Some of these events seemed to be a little strange.

In 1936, physicist Carl Anderson, decided to study these events. He must have spent quite a bit of time looking at his scintillation chamber. He eventually collected enough observations that he could make some calculations. There was a particle that would occasionally enter his scintillation chamber that behaved almost like an electron. It was negatively charged like an electron. It’s negative charge was the same as that of an electron. However, it was more massive than an electron. What could it be?

Scientists were busy inventing particle accelerators. Particle physics was about to become an important field giving us valuable clues about the ultimate ground of matter that no one had ever dreamed of before. With the advent of particle accelerators, particles like Anderson had seen were produced in abundance and on demand. Their mass was almost 200 times that of an electron … which is still much smaller than that of a proton. So where did this fit into the scheme of things? It didn’t. In fact, its discovery prompted one physicist to remark, “Who ordered that?” But in any case, another subatomic particle, the muon, was discovered. The number of subatomic particles now jumped up to 4.

Well, it turned out particle accelerators produced all sorts of subatomic particles. All of a sudden, things did not look so elegant. Instead of 3 elementary particles (or even 4 with the inclusion of the muon) there were dozens and dozens with no reason to suspect there might be an end. Perhaps the subatomic particles were themselves composed of particles that were more basic than themselves. In agreement with that was the finding that many of these subatomic particles could be changed from one into another. So what were the fundamental building blocks of matter?

For an answer to that question we can thank Buddhism and the novel Finnegan’s Wake. Or more accurately we can thank physicist, Murray Gell-Mann. Gell-Mann found a way of arranging a class of subatomic particles (spin ½ baryons) into an order he called The Eight-fold Way (after the Buddhist Eight-fold Path to reach nirvana). Gell-Mann’s method involved arranging these baryons into conceptually into octets. By doing so, baryons with similar properties grouped together very well.

Furthermore, the principals he used to group the spin ½ baryons could be used to group spin 3/2 baryons as well. In doing so this class of baryons should group into decuplets (groups of 10). However, when he did this, there was a bit of a problem. One member of the decuplet was missing. It had not yet been found.

As it turns out this was not so much of a problem as it was an opportunity. By looking at the space such a particle should fill, Gell-Mann was able to predict that a particle with those exact properties should be found. Particle physicists were more than happy to test such a prediction. All they had to do was fine tune the accelerator to the energy level that Gell-Mann said the particle should have and see if the particle was produced. And OUILA! There it was … just as Gell-Mann predicted.

Another thing that one could derive from Gell-Mann’s theory was the idea that protons and neutrons must be made of 3 more basic particles tightly bound together. Gell-Mann called these particles “quarks” (from a line in the novel Finnegan’s Wake -- “Three quarks for Muster Mark!”).
Gell-Mann’s Eight-fold Way has evolved into the Standard Model of Particle Physics. In this model matter is made up of 16 different particles. There are 6 quarks (up, down, charmed, strange, top, bottom); 6 leptons (electron, muon, tao, electron neutrino, muon neutrino, tau neutrino); and 4 force carriers (photon, gluon, Z and W boson)

That is where the state of scientific knowledge is today concerning the basis for matter. In many ways it is a satisfying picture. It covers everything that we know and no observation has ever contradicted it. It reduces the number of elementary subatomic particles from several dozen down to 16.

Or does it? In point of fact, it is actually twice as bad as that. We now know that for each of those matter particles there is a corresponding anti-matter particle. So the real number of elementary particles is 32. Thirty-two particles! Why so many? Couldn’t the universe have started out with fewer? Remember that Democritus and Lucretius wanted there to be a single one.

There is a practical point as well. If the universe came into existence on its own, as most scientists think, then does this model mean that 32 different subatomic particle species had to spring into existence together?

Physicists have been looking for a more elegant solution to the question for a long time. Perhaps they have already found it. The solution that is most favored by physicists today is “String Theory”. String theory postulates that these 32 particles are all formed from a single type of particle … a very tiny vibrating string.
So how could a very tiny vibrating string give rise to the “particle zoo” of the Standard Model? The only way is for the strings to be vibrating in different dimensions.

We live in a world of 3 spatial dimensions. Take a piece of paper. Draw a line in any direction you want on that paper. That represents one dimension. Then from an end point of the line you have just drawn draw another line that is perpendicular (90^o ) to the first line. That represents the second dimension. Then from the point where those two lines intersect, hold a pencil that is straight up or perpendicular to the other lines. That is the third dimension. For everything we normally do, that is it. There are no more spatial dimensions.

One problem with string theory is that to produce the particle zoo, three spatial dimensions are not enough. One needs nine, or even more likely ten. For there to be 10 spatial dimensions there would need to be a point at which you could visualize 10 different lines coming off in which every line is perpendicular to every other line. That is something I certainly cannot visualize. And I don’t think anybody else can either.

String theorists tell us that simply because we cannot visualize these extra dimensions do not necessarily mean that they don’t exist. Perhaps, 7 of the 10 dimensions are folded up. Another way to think of it is that when the universe expanded during the Big Bang, that expansion involved only 3 dimensions and the other 7 never expanded at all.

Quantum physics tells us that there is a limit to how accurately it is possible to observe the universe. As we look at smaller and smaller spaces we become less and less able to make out details such as the energy that resides within that space. At some point our uncertainty about the energy within that space approaches infinity. This distance is called planck’s length. It is equal to about 10^-35 meters. This is a very small space, much smaller than a proton (the nucleus of a hydrogen atom). This is the level where string theorists postulate the other 7 dimensions arise. It is also the size of the vibrating strings.

The beauty of string theory is that it is consistent with what we already know. Furthermore, it reduces the particle zoo from an inelegant 32 to an elegant 1. It may even be true. But at this time, despite the fact that many scientists are working on it, I do not consider it science.

Why not? The reason is, up to this point, string theory has not made a single verifiable prediction. It COULD be true. But it may not. Until string theory does make a verifiable prediction it lies outside of science’s ability to test it. That means it is not yet properly science.

We cannot look at things directly at the level of planck’s length. Indeed, we will NEVER be able to do so. By definition at that level things become infinitely uncertain. In order to verify string theory we will have to look at things much larger than the strings themselves. What offers us the best chance of doing so?

The answer to that question is more powerful particle accelerators. The most powerful one ever designed (the Superconducting Super Collider which was at one time being built in Texas) unfortunately did not survive a Congressional line item budget cut. The Swiss-built Large Hadron Collider (LHC) is coming on line and having its bugs worked out. Will it be able to produce high enough energy collisions that would allow us to detect events close enough to planck’s length to verify string theory? Not without a further clarification from string theorists about what we should expect to see. Will they be able to do that? I frankly don’t know. I don’t rule it in or out. But I look forward to seeing what new things at finer and finer levels the LHC will show.