Physics and reality
(Talk for Charleston Unitarian fellowship, July
By James A. Haught
As you know, I give science talks to the kiddies - and now I'm doing it for the adults. The message I want to make clear, if I can, is that physics has profound philosophical implications. In fact, it may be the single best clue in shaping a person's grasp of the existence that engulfs us.
We all know what reality is. We're born into
it. We live in it. We die in it. We have physical bodies. We eat physical
food. We drink physical water. We breathe physical air. We wear physical
clothes. We enjoy physical sunshine and blue skies and green hills. Reality
is so all-encompassing that we rarely think about it.
However, if you study physics, as some of us
in the adult discussion circle do, you begin to see that reality isn't quite
real, after all. It's a mirage - a fiction - a fantasy. The deeper you go
into physics, the more you come to a spooky awareness that nothing is what
Take matter, for instance. (RAP PODIUM) That's
solid, isn't it? Hard knuckles on hard wood. But wait - it isn't solid at
all. It's an illusion of electrical charges. The negative electron clouds
in the atoms of my knuckles repel the negative electron clouds of the wood
atoms, creating a false impression of hard contact.
The same rule applies to virtually all matter.
(STOMP) When you step on the floor or sidewalk - or sit in a chair - or
lie in a bed - you feel tangible firmness only because of negative electron
If you could shrink to atom-size, to examine any of these "solid" things, you couldn't really find them. Approaching an atom, you'd come to a blur of whirling electrons. (Of course, you couldn't SEE them in the usual sense, because they're smaller than the light waves that register on our retinas.) But if you could somehow detect the electron haze, you couldn't find the nucleus at the heart of the atom, because it's incredibly smaller. It boggles your mind to realize how empty an atom it is. If an atom were the size of a 14-story building, the nucleus would be the size of a grain of salt. It's like the sun at the heart of the far-flung solar system. Looking inside an atom would be like looking into the night sky, with its remote planets. That's how far apart the subatomic particles are, relative to each other. So, if you could approach any "solid" material at the atomic level, you'd find only emptiness, like the vast gulfs of the solar system.
(Many years ago, I heard the bizarre theory that our atoms might be solar systems of an unthinkably smaller universe - and that our solar system might be an atom of an unthinkable bigger universe. Once, the great astronomer Harlow Shapley made a talk at West Virginia State College. As a gawky young student, I hung around afterward and asked him: What's the name of this theory that atoms might be solar systems? He stared at me and said: "The name of it is damn nonsense." Well, I later learned that it's called the Subatomic Universe Theory - but I think Shapley was correct.)
I tossed that in to show how astounding physics can be. For example, it's now fairly clear that everything on this planet is made just from four matter particles - electrons, up-quarks, down-quarks and neutrinos - which react to four force particles such as the photon. But what are they? Maybe they aren't particles at all - only waves. And the new superstring theory says they're all the same thing: tiny loops of string, vibrating in different ways. In truth, nobody knows what the subatomic particles are. One physicist called them "the dreams of which stuff is made."
Getting back to the vast emptiness inside atoms: It's so awesome that you can't comprehend it. The only way to grasp it is to see what happens when the emptiness is "squeezed out" by gravity, and the particles are compressed down close to each other. This happens in several steps under immense gravity in a collapsing star.
First, you must realize that the matter in a star isn't like matter on earth. Here, we have three states: solid, liquid and gas. Solids occur when atoms lock onto each other in what is called a crystal lattice. Liquids occur when heat makes the atoms so agitated they break out of the lattice and slide around each other. Gas occurs when more heat makes them so jumpy they break loose and ricochet wildly in open space.
But stars have a fourth state of matter: plasma. Intense gravity compresses the atoms so much that the pattern of orbits around a nucleus is crushed. The electrons are squashed into a dense "soup" dotted with roaming nuclei. Without orbits to shield them, the nuclei collide with each other and fuse. This nuclear fusion is what makes stars burn (and makes hydrogen bombs). Its incredible power derives from a tiny amount of matter converted into pure energy under Einstein's famous formula: E=MC2. Any mass of material, if it's big enough for its own gravity to squeeze it into plasma, becomes a star. The planet Jupiter is almost large enough. In fact, astrophysicists think a tiny amount of fusion is occurring in Jupiter's heart.
Now, back to the step-by-step elimination of emptiness inside atoms: When a collapsing star is of a certain size, its gravity squeezes the plasma ferociously, until the electrons push back with enough resistance and prevent further collapse. This is a "white dwarf" star - and its substance is astounding. It's 10,000 times denser than steel, and weighs 10 tons per thimbleful. Nothing on planet Earth is remotely like that. Can you imagine a thimble that couldn't be lifted by 100 strong men?
But that's only the first stage of collapse. A brilliant Indian teen-ager, Subrahmanyan Chandrasekhar, figured out that if a collapsing star has mass 50 percent larger than our sun, the electron resistance will be overwhelmed. What results is a pulsar (neutron star). The mass's huge gravity crushes the electrons into the protons of the nuclei and makes a solid mass of neutrons. The matter in a neutron star weights 10 MILLION TONS PER CUBIC CENTIMETER. Think of it: a bouillon cube weighing as much as the Empire State Building.
Next, a collapsing star more than 3.4 times the mass of our sun won't stabilize at the pulsar stage. Its gravity is too colossal to stop there. It proceeds to total collapse, into a black hole, which is utterly beyond human understanding. The dimension at which compressed matter becomes a black hole is called the Schwarzchild Radius. For Planet Earth, this radius would be the size of A PEARL. Can anyone imagine this entire planet squeezed down to the size of a pearl? But that's what matter is without empty space between particles.
All this shows that matter is 99.99999 percent void - just an illusion of whirling electrical charges. If a c.c. of matter from a pulsar weighs 10 million tons, how much actual matter is in a 200-pound person like me? If the empty space were squeezed out, there wouldn't be enough to see with a microscope. We think we have substance, but we're composed of NOTHING.
However, regular, everyday matter is the only reality in our lives. Atoms in steel may be as empty as the night sky, but a steel knife can cut you. Even though it isn't real, it's extremely real to us.
Consider a bass string on a piano: a long wire coiled into a tight spring. It's so rigid that it will hold its stretch for many years, vibrating at the prescribed pitch. Yet the atoms of that wire are clouds not touching each other, merely attracted by the valence gaps in their electron shells. How can untouching clouds make hard metal that no person can pull apart?
Meanwhile, physics reveals many other bafflements:
-- Although electrons peacefully occupy every atom of your body, they're violent when detached. Lightning bolts are cascades of electrons.
-- Electrons have a quality called "spin"
(but it doesn't mean whirling) - and it can be used to suspend railway trains
in the air. In most atoms, electrons are in pairs with opposite spin, neutralizing
them. But in iron-type atoms, some electrons aren't paired, and the unbalanced
spin makes each atom a magnet. When an electrical current causes all the
atoms to line up in the same direction, the result can be an electromagnet
strong enough to make "maglev" (magnetic levitation) trains float
-- Last year, a new astronomy study established
that the Milky Way galaxy is rotating at such a rate that our solar system
is moving 135 miles per second. This means that we West Virginians are traveling
about 800 miles an hour with the rotation of the planet, 67,000 mph in the
orbit around the sun, and 486,000 mph in our trip around the galaxy - yet
we have no awareness of moving. (In comparison, a bullet goes 3,000 miles
-- Also last year, a NASA study pegged the age
of the universe at 12 billion years. When we look at some stars, we're seeing
light that left them hundreds or thousands of years ago. They've moved -
and perhaps exploded - since then. Our eyes see the past.
-- Relativity says that time slows and dimensions
shorten as speed increases. This seems impossible, but many tests have verified
-- Einstein's great equation, E=MC2, showed the
colossal power that's released when matter turns into energy. An amount
of matter smaller than a dime changed into energy at Hiroshima in 1945.
-- Each human cell (except red blood cells) contains
about six feet of DNA, and you have many trillions of cells, so your body
contains SEVERAL BILLION MILES of DNA.
Well, the point I'm trying to make in this long
spiel is that we live our entire lives in what we THINK is reality - but
physics shows us that it's at least partly an illusion. Nothing is real
in the way we think it is. And that has awesome philosophical significance.
Let's go to questions.