Skeletons in the Physics Closet
Cleaning Our Own House
The neutrino and energy conservationhttp://www.ethbib.ethz.ch/exhibit/pauli/neutrino_e.html
Prof. Scalise discussed a few weird things about modern physics. There are a few skeletons in the closet here, too.
The study of matter and energy is a principal part of physics. The goal is to understand how matter and and energy behave and, hopefully, how it all works. Matter is interesting stuff. It seems solid enough, but is really almost entirely empty space. If you could magnify an atom so its electron shells were the size of Texas Stadium, the nucleus would be the size of a baseball at the center. Everything in between is empty.
In the nucleus you find protons (positively charged) and neutrons (not charged). They were long thought to be solid particles, although very tiny.
Prof. Scalise used an example of the phenomenon called scaling. Consider a ball of red yarn. Completely ordinary ball of yarn maybe 4 inches in diameter. If you view it from a mile away it will appear as a red point. Move in to 20 feet and it is a red sphere. Get closer, like 5 feet, and the yarn becomes visible; it looks like a 1-dimensional string all wrapped up. At 1 foot you can see that the yarn actually has diameter; it is a long cylinder all rolled up. Now really close in on it, getting 2 inches away from it. Now you can see the individual tiny threads in the yarn.
The appearance of the yarn ball changes as you get closer (magnify it more). It goes from point to sphere to textured sphere to rolled-up line to rolled-up cylinder to many threads. Such an object does not scale.
So what does this have to do with protons? In 1969, some physicists did an experiment, smashing tiny electrons into protons at increasing energies. The way the electrons bounced off, plus the production of heavier versions of the electron and the proton, revealed that the proton is not solid but has three parts. These parts were christened quarks.
Over a wide range of energies (magnifications) these quarks look like points without any internal structure.
There are six types of quark: up, down, top, bottom, charm, and strange. The names are physically meaningless - they just refer to 6 different quarks. A proton is made of two ups and a down, while a neutron is two downs and an up. This work was good for a Nobel prize in physics.
Current Strangeness (not quarks)
We were just talking about an experiment - "real physics" to many. But there's more to physics today. Mathematical theory is quite prominent. There are three primary areas of this.
- String theory
Supersymmetry postulates that for every ordinary atomic particle there is a heavier symmetric partner. The only problem is that the supersymmetric partner particles have NEVER been seen in experiment. The masses of the partner particles is predicted to be large but seems to be quite uncertain.
Formalism, the third area, is work beyond the current model of particles.
These three theoretical areas have one property that many physicists don't like: they cannot be tested with experiments. Some (including Scalise) argue that these areas should be classified as mathematics.
The final strangeness lies in the National Science Foundation's funding for physics research.
- 24% String Theory
- 23% Supersymmetry
- 17% Beyond Standard Model
Books and Articles:
- The Trouble With Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next by Lee Smolin
- Not Even Wrong: The Failure of String Theory And the Search for Unity in Physical Law by Peter Woit
- The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory by Brian Greene