Sunday, February 10, 2019

God and the proton

The proton is remarkable. It is the perfect electrical counterpart to the electron, having exactly equal but opposite charge, thereby enabling the stability of neutral matter (atoms). And yet, the two particles could not be more different 1. The electron is (as far as we know) fundamental (non-composite) while the proton is a right-royal mess. 2 Naively thought of as three quarks (a picture that is woefully inadequate) a proton is actually complicated interacting soup of quarks and gluons, and its properties arise from the aggregate effects of this subatomic quagmire. Its fundamental characteristics are only beginning to be unraveled. 3

Our universe gives the appearance of being fine-tuned to create heavy elements, the ingredients of rocks and of life.4 These heavy elements are forged inside of stars. The scientific theist would indeed agree with Genesis that we are made of dust—star dust to be precise, the (providential) remnants of an exploding star.

The existence of stars is not, by any stretch of the imagination, a foregone conclusion. It depends on a detailed balance of the initial conditions of the big bang. A change in any number of factors (e.g., the absurdly small value of the cosmological constant, the baryon density, etc.) and we could have easily had, just post big bang, too fast or too slow of an initial expansion. If too fast the universe would be too diluted to form stars, and if too slow there would be a rapid reversal into big-crunch. In either case: no rocks and no life. So stars themselves are rather unexpected, should you merely pop a universe into existence via a big bang of random initial conditions and physical constants.

But even given, on a silver platter, a universe that produced stars, you would not be home free. For the nuclear fusion furnace inside of stars is a veritable house of cards as it synthesizes heavier and heavier elements.5 The fusion chain relies on the relative strengths of fundamental forces, on fortuitous excited states of nuclei that permit the process to proceed at a decent clip, and yet quantum selection rules to prevent it from occurring too rapidly, lest all the material get converted to iron leaving the star with no lighter elements like carbon and oxygen (those are kinda important!) to seed the universe with when it obligingly explodes. (The explosion itself relies on some rather happy coincidences.)

As you dive deeper into serendipity of heavy element production (creation?)  you always end of at the same place—the remarkable properties of the lightest nucleus—the proton, viz.6 Its mass relative to its sister, the neutron. The fact that it just barely binds with the neutron, and doesn’t bind with another proton, both features necessary to avoid catastrophe. Its infinite or effectively infinite stability to decay.

I could go on. There is a laundry list of proton properties that are necessary if the universe is to produce the building blocks of rocks. And life.

My much smarter colleagues at Jefferson Lab have uncovered a new property of the proton. In the center of the proton there exists an outward pressure a hundred times greater than that found inside of neutron stars, cosmic objects (end of life stars) that are almost black holes; typically about 20 km in diameter and more massive than our sun, neutron stars that are so dense that a single teaspoon would weigh about a hundred million tons. Consider that for a moment: the humble proton, the building block of all normal matter, has at its tiny center an outward pressure greater than that of a neutron star. And yet—it is stable. Very stable. It doesn’t “explode.”

I think about my friends and I applaud and marvel at their achievement. I know that along with them I find it remarkable and beautiful. And yet I think (I don’t know for sure) we reach different metaphysical conclusions. I immediately think of Psalm 19:1. While I guess they are more of the Laplacian: Je n'avais pas besoin de cette hypothèse-là.

I don't know how to explain that. It just is.

1 Given the electromagnetic force is about 1037 times stronger than gravity, if matter were not neutral the electrical forces would dominate, and there would be no large scale universe; no galaxies, stars, or planets.

2 The present upper bound on the size of the electron is about 10-18 m. (There is no experimental lower bound, so the electron could be much smaller than the present upper bound.) All current theories postulate it to be a point-like fundamental particle, i.e. it is not made of smaller constituents. The proton does have a discernible radius of about 10-15 m, small but roughly 1000 times bigger than the upper bound of the electron size. Furthermore the proton, far from being fundamental, is complicated composite of quarks and gluons.

3 And Jefferson Lab is at the forefront of much of the investigation.

4 The term fine-tuned is agnostic about the question of whether there exists a sentient fine tuner. Anyone who complains about the term fails to realize that we often anthropomorphize terms in science. We say things like: “the electron knew which slit to pass through” and “nature hates changing the magnetic flux.” Fine tuning is merely descriptive of the fact that the existence of stellar nuclear furnaces where the ingredients of rocks (and, as a happy byproduct, life) are forged appears to be so sensitive to the values of the physical constants that many believe the only non-supernatural explanation is the multiverse. Of course, if you are a theist there is nothing stopping you from taking the term more literally (and why wouldn’t you?). But even the theist should acknowledge that the phrase was not coined to be supportive of a universe designer.

5 Up to iron. The heavier elements, many of them ingredients of life, are created during the explosion (supernova) of large stars.

6 The proton is (is also?) the nucleus of the simplest element and consummate nuclear fuel: hydrogen.


  1. I am a muggle, but this is really cool.

  2. Another good one. A great reminder of the work of the Intelligent Designer. (I'm not a great fan of the ID movement, if that matters.)