What's a matter?

January 2006

Abstract:
Of the evanescence of elementary particles. Soon the theories of physics may coalesce into one where matter no longer matters, because it isn't really there.

• An eighteenth century Newtonian physicist might say that two solid bodies (the marble and the Earth)  in a perfectly elastic collision transfer momentum to each other proportionate to their masses.  Thus the marble bounces up, while the somewhat larger Earth barely budges.  The solid bodies may be (he might say) composed of indivisible "elementary" particles called atoms.
   
• A nineteenth century physicist might answer that the molecules involved are thought to be mainly empty space; but the atoms composing them, no longer indivisible, are made up of solid, indivisible protons, neutrons, and electrons, held together by electric and other forces.  They behave like solids because of tight bonding and rapidly spinning electrons.  So solidity is still there, indivisibility is still there, but they're at a more fundamental level than in the last century.
   
• A twentieth century physicist might explain that the atom's protons and neutrons are built up of solid, indivisible elementary particles called quarks, held together by nuclear forces.  So solidity is still there, indivisibility is still there, but they're at a more fundamental level than in the last century.  The atoms' and molecules' various forces interact to create force fields that present themselves to our perception as solid bodies, reflecting even photons of light.  One set of force fields (say, the sidewalk's) will not permit the intrusion of another – the marble's, and so they reject each other, exchanging momenta proportionate to ...  etc, etc.
   
• And a contemporary physicist might hold to the "superstring" theory, in which the quarks have yielded to even smaller component "fundamental" particles, this time vibrating "strings" billions of times smaller than even the quark.  But what is the "string"?  In the view of modern physics, it's a particle, solid and indivisible like all the others.  So solidity is still there, indivisibility is still there, but they're (again) at a more fundamental level than in the last century.

And thus, solid matter has been on a long retreat in physics, fighting a losing theoretical battle against fields of electromagnetic energy.  The comfortable reality of what once was thought to be solid matter has vaporized in modern physics, the solidity proving to be merely electromagnetic force fields surrounding a few quirky quarks.  Matter is now seen to be 99.99999... (you could add a hundred 9's) percent empty space.  When we studied the atomic theory in school, we learned about tiny negatively charged electrons whizzing around the atomic nucleus at fabulous speeds.  Well, the electron may not be there any more.  It has been dismissed by some physicists and physical chemists;  put under a cloud, as it were.  All that's left of it is an electromagnetic field with probabilities of partial negative charges at indeterminable locations around the atomic core.  Turns out that almost everything about chemical bonding makes more sense if the electron is not particulate, is not "matter" at all.  Yes, it still registers on our most sensitive detectors as a track that we call a "particle", but that may say as much about our detectors as about the electron.

But at least the nucleus is still intact.  Isn't it?  Elementary particle physicists are hanging on to their solid particles for dear life, be they quarks or "strings".  This last bastion of solidity, the atomic nucleus, must not be allowed to go the way of the electron!  What would become of Relativity Theory, what of Einstein's  e = mc²  (whose centennial we've just celebrated)  if there is no matter; if there's no "m" to relate to "e"?  It would be reduced to gibberish.  No, we will insist on the solidity of particles!

But do physicists really have any evidence for the "solidity" of any particles?  No, not really.  It's just an assumption, arrived at through a gradual retreat from the earlier belief in matter's total solidity, then taking refuge in a belief in the solid mass of at least protons and neutrons, and now taking the same view of the newer component "elementary" particles.  Our senses and sensors of a hundred-odd years ago would have registered my coffee cup as a solid object, but it lost its solidity, as it were, during the 20th century.  But though our sensors have improved, are we any more justified in interpreting our current photo images (of tracks from "particle" scattering) as evidence of elementary solid bodies?  Not at all;  it's a leap of faith that's unwarranted, no matter how strong the physicists' need for belief in the existence of solid matter;  and it may have been leading physics down a blind alley during the past few decades.

What then if physicists' assumption of particle solidity, i.e., the existence of actual "matter", isn't correct at all?  What if, analogous to the "electron", the proton – or the quark, or the string – is just a densely localized positively charged electromagnetic field, fairly stable because it is in equilibrium with the negative charges of the "electrons"?  Then what we call matter is nothing but electromagnetic fields, there is no matter left, all is energy, the equivalence of matter and energy would be a triviality, Einstein is right but tautological in E=mc² (as we indicated in the the above-referenced essay), gravity becomes a feature of electromagnetism, antimatter is just electromagnetic fields with reversed polarity, and a Unified Field Theory becomes child's play.

The disappearance of solid matter could initially be a psychological blow to humanity.  It's bad enough to know that we're 99.99999... percent empty space (though few actually know that);  knowing that we're all empty space might send us over the edge.  Imagine the Pope's first disgusted gut reaction to this heresy.  But soon a bright junior Cardinal would explain to him that this new discovery confirms the Church's ancient teaching:  Our bodies are ephemeral;  our real essence is immaterial and spiritual, and our eventual reunion with the Creator will be as souls  ( – and don't we here have the ultimate definition of the "soul":  a personalized electromagnetic field! – )  and not as bodies.  Which, I suspect, will be a relief to a lot of people.

The response of the scientific community will be, I think  –  after the initial skepticism of elementary particle physicists who have spent a career chasing and naming their particles  –  one of relief. 

Seems like a natural progression, doesn't it?  The atomic nucleus disappears, just like the electron, and all is twisted space.  Turns out then that Newton's laws of force and motion describe the behavior of electromagnetic fields.

Naturally no self-respecting physicist (nor any of the other sort) has proposed such a theory in print  – though there may be those who have mused over it –  so it's left for us amateurs to take this giant leap for mankind.  I believe that gives us the right to name the theory.  Let's go with "MERGE" theory, named for what the theory would unify:  Matter, Energy, Relativity, Gravity, Electromagnetism.

Perhaps this whole business won't make any real difference to us.  The child's marble still bounces on the sidewalk . . .  Or will it lead physicists to find more subtle ways to harness the limitless energy around us, thus multiplying endlessly our possibilities as a species?  That should be a hopeful thought at this New Year.  But things being as they are, hope may properly be mixed with apprehension.