It's fun, it really is.
I have had a secret plan, secret no more, I guess, to develop an evening series of classes on modern physics for the non-physicist. It would not have any mathematics, or any other hard stuff, but deal with some of the remarkable consequences of what physicists know, and don't know about our world. Actually, the course would have "hard stuff", and that would be conceptual, requiring you to absorb new ideas about our world.
Small stuff
Our perception of the small keeps getting
smaller. In historic time people knew about atoms, then we learned about
protons, neutrons, and electrons that make up atoms. They are very small.
Then scientists found out that those particles, and many more, were made
up of quarks, which are really small. They are pretty interesting.
There are eight types in four pairs, Up & Down, Strange & Charm, and Top
& Bottom. They also have "color", Red, Blue, and Green, which has
nothing to do with color as we know it. The particles of ordinary matter
are combinations of Up and Down quarks, while the other four quarks are
constituents of more exotic short-lived particles.
"Gluons" act like rubber bands that hold the quarks together. But that doesn't explain everything. Particles really behave like vibrating strings. They are really, really small, about 10-13 cm in length. Recent theories show that the strings are really small loops about 10-32 cm in diameter. The way they vibrate determines what kind of particle it is. Not only that, but mathematical evidence is emerging that the loops are actually membranes, or surfaces.
Dimensions
How many dimensions are there anyway?
Three? Four including time? Well it turns out that some of the recent
theories show that there are 10 spatial dimensions, plus time. Seven of
the ten are curled around themselves so tightly they don't show up in the normal
world, leaving us with the three we see. In fact, they have never have
shown up, they are only proposed to exist because the most current mathematical
descriptions of matter require that they exist. The membranes mentioned above
exist in yet another dimension.
What is really amazing is the range of size from the cosmological to the sub-nuclear. Soon I will put a discussion here that I hope will dramatize the range.
Mathematics
Physics is really tied closely to math, and the math
required in modern physics is probably the most difficult math ever
developed. I have often wondered why there is such a link. Does that
mean that if something is mathematically true, it must be physically true?
Well, no. The math must explain the phenomenon we observe. The math
was not always so complicated. When F = Ma was
discovered, that was an example of explaining physical observations through
math. When Albert Einstein came up with E = Mc2, that was another example. The trouble is that now
the equations are much more complicated, and sometimes required the development
of complete new types of mathematics. But that is not new either.
Sir Isaac Newton had to develop "The Calculus" to explain the motion of planets
in our Solar System. A mathematical model is really useful when it
predicts observation that have never been made before. The bending of
light around a star or a black hole is a good example of that.
Explaining Everything
Finally we get to the search for the "Theory
of Everything". This would be a theory that unifies all forces that we
know of, and there are four: The Strong, Weak, Electric, and
Gravitational. These govern the reactions between matter, whether it be
something as small as quarks, or as large as galaxies. The hardest to
include with the others is gravity. The closest we have gotten to the TOE,
is supersymmetry, which postulates that for every matter particle, there is a
force partner and for every force, there is a corresponding particle. The
energy required to see most of these effects in an experiment is so large that
we haven't conceived of how to demonstrate all of these pairings. We have
experimental evidence of some, though.
Matter and Antimatter
Why is there matter? Why is
anti-matter so rare? The symmetry principle of modern physics say that, in
general, matter and anti-matter are created in equal amounts from energy.
We know that when matter interacts with anti-matter, they annihilate each with a
burst of energy. If that is so why hasn't it all been annihilated by
now? Well, it turns out that at the instant of the "Big Bang" everything
was so hot and dense that symmetry was violated, and just a little bit
more of matter than antimatter was created. For every 30 million particles
of anti-matter created there were 30 million and one particles of matter.
Less than 0.000001 percent. This happened when the universe was about one
billionth of a second old. Well, what we and the whole universe are made of, is
that little bit of leftover matter. Everything else was annihilated in a
short amount of time after the big bang. The rest is energy from the
annihilation and makes up the background radiation of the universe.
Relativistic Effects
Coming soon... or a little later.
Really fun.
Links
Here are video trips to unusual objects, in which the
gravitational effects on light, and other relativistic effects are dramatized.
Virtual Trips to
Black Holes and Neutron Stars Page
Here are some other links I have found recently:
Here's a discussion of The Big Bang by Michael Guidry of the University of Tennessee, and Oak Ridge National Laboratory.
Here's a link to a NASA page discussing their planned Microwave Anisotropy Probe which should tell us a great deal about how the universe developed. Introduction to Inflation
Here's link to a very interesting set of links by Hugh Blackmer. Quantum Mechanics. Many of the items are heavy going though.
More from Hugh Blackmer Physics, Fractals, Computer Science. These are more fun.
More to come.
Basic Physics
The best book on superstrings, hidden dimensions and the quest for the ultimate theory: