I took my last physics course (on classical thermodynamics and statistical mechanic) 50 years ago. I never had former courses in quantum mechanics or general relativity theory beyond what I pick up from newspapers and magazines. Since then my own research and further learning had little to do with the physical (vs. the man-made) world. Thus, knowledge-wise I am a caveman when compared to a professional modern physicist. Consequently, it is gratifying that I caught 2 one hour programs of the most entertaining and understandable kind of  TV documentary on the Science Channel the other day. They are 1. The Big Bang Machine, and 2. What on earth is wrong with gravity? The star/author is Professor Brian Cox of the University of Manchester, England. After the two hours of viewing, I feel I had a consistent understanding of the big picture of modern physics of the past 50 years. If DVD of the programs is available in China, I urge every scientist/engineer to buy or rent it for viewing.

 

Here is a summary of what I learned about modern physics of the past 50 years. I sincerely ask any physicist reader of ScienceNet to correct any wrong impressions I have gathered.

1.                  At the atomic level, we learned that there are 16 fundamental particles (not protons as I was taught in college physics then) that make up atoms. A “Standard Model” of these particles exist to explain all the experimental evidences we learned when we smash protons together (you smash protons together to find out what they are made of) http://en.wikipedia.org/wiki/Standard_Model.

2.                  However, this standard model has two known “defects”:

a.       It does not explain where the “MASS” of a particle comes from

b.      The mathematics of the standard model requires pages and pages of formula. Scientists universally believe that a correct theory is basically simple and elegant. E.g. E=mc^2, or Newton’s law of gravitation.

3.                  A conjectured answer for question 2a is provided by Scottish scientist Peter Higgs (http://en.wikipedia.org/wiki/Higgs_boson) who predicted the existence of an elementary particle called the “Higgs Boson”. However, to date it has not been observed. The Large Haldron Collider (LHC,the big-bang machine of program 1 above; costing many billions of dollars to built) in Cern , Switzerland that will be fully operational in late 2009 and supposedly can answer experimentally the existence question. Should this fail, the correctness of the standard model and several Nobel prizes awarded in the past 50 years may be called into question. Note added 8/9/09: The Sunday New York times "review of the news this week" section had a lead article this morning about the delay and setbacks at the LHC machine (the big bang machine mentioned above) that raises doubt concerning if it will ever answer the question we all like to know.

 

4.                  If the Higgs Boson can be proved to exist, then the mathematics of the standard model can be greatly simplified and doubt 2b above can be put to rest.

5.                  Einstein’s relativity theory had been further verified more accurately (beyond the famous sun eclipse experiment of the early 20^th century) after the moon landing and gain in knowledge of the cosmology of the early universe 7 billions years ago. Most interestingly, I learned that the clocks in the 30 some satellites that constitute the GPS system used in modern autos would be off by 10 kilometers per day if they are not corrected according to Einstein’s general relativity theory of space and time (The clocks in the satellites actually runs a bit slower than clock on earth. Thus, they have to be re-synchronized every hour with the earth-based clock for position determination purposes).

6.                  Einstein’s theory is very elegant and explains much of modern cosmology. However, when it is applied at the atomic level, the theory breaks down. Thus, it is incompatible with quantum mechanics. We need a “Theory Of Everything”. Einstein himself realizes this and spent his last 30 years of his lifew tried but failed to do it. The modern and still controversial “String theory” is a leading candidate for TOE. It throws away the concept of elementary particles and postulates that the most fundamental thing in the universe is vibrating strings. Different vibrating frequencies of the string create different particles which constitutes the standard model.

7.                  The String theory is controversial because mathematically it is still not elegant and simple enough. There are too many “fudging constants” and require the existence of many extra dimensions and possible parallel universes - concepts difficult even for scientists to accept readily and cannot be tested experimentally at present.

8.                  All these efforts are directed towards the ultimate question – “how did the universe begin and where did it come from?”

9.                  These two programs also eloquently answer the question why we and the government spent money to do basic research with no obvious direct benefit to society?