The first day of physics 101 the students were told to expect at some unannounced point in the course to hear a lecture from a Doctor Starling, just like the bird starling, who was not on the faculty and who was not actually even a professor of anything. He was the harmlessly insane son of a wealthy benefactor, and to get the big big money the college allowed Starling to present guest lectures when Doctor Farris was ill. Starling thought he was a famous astrophysicist and this was Princeton.
We were instructed that while polite questions were encouraged, long discussions and out-of-class contact was not. We were to accept everything he said at face value, and under no circumstances would we cackle or smirk if he dropped the names of his good pals Hawking or Sagan.
We were excused from his lectures at our own discretion, but certain upper classmen convinced me that it was worth hanging around for an hour. That if I skipped his lecture, curiosity would get the best of me and I'd end up asking my classmates about it and would not be satisfied with their descriptions.
When he finally showed up it was a damn disappointment. The guys who told me Doctor Starling was eccentric were more than a little out of round themselves and I was looking forward to a right smart Daffy Duck display. I walked into class and saw this guy at the blackboard, pushing maybe forty. His tie was snugged to his throat, but you could tell his collar beneath was unbuttoned. He still had enough hair so nobody would call him bald or even balding and there was a horizontal bloodshot streak in one eye as if he'd been punched in the eye long ago and it had never healed properly. He didn't twitch or bark or throw clams at the moon as he wrote on the board, "Mister Starling."
"Hello, my name is Mister Starling. Doctor Farris is ill today and I'll be presenting a lecture on the subject of gravity. It is not part of your curriculum and you will not be tested on the material. Any of you who wish to be excused may leave now."
I thought about leaving, and I guess everybody else did, too. He looked about as bizarre as the manager of a Wendyburger, which is to say, not the least bit bizarre. I turned around to see if anybody else was leaving and saw that there were in fact extra people in class that day, centrifugally stuck to the back walls. Some I recognized. Some I didn't.
I started thinking right about then that this was a practical joke they played on the freshmen. I had heard stories about fraternities at this place. They'd entirely empty some guy's room and reassemble it in the street. Over a freezing cold weekend, somebody had covered a dorm floor with an inch of jello and left a window open so it would jell.
Maybe Doctor Starling was the faculty taking their shot at the students. That would explain the extra faculty members that showed up. They wanted to see the fun. They wanted to see how these freshmen reacted to whatever stunt was about to be played. A lesson on gravity? Were we going to find ourselves knocked to the floor, or was something going to fall on us from the ceiling? Everybody else was staying, so I stayed.
I missed a lot of the lecture because I was anticipating some kind of disruption. There was no disruption. It was just a lecture by a sincere, well-meaning goofball who had apparenty picked up his knowledge of gravity from the back of a cereal box, and the gist of what he told us was this:
Gravity is actually particles. It's not a field. It's not a force. It's not a property of matter. Matter is described in terms of gravity rather than the other way around. Mass is related to the number of gravity particles (Doctor Starling called them "gravitons") that are stopped in a volume of space. If a thing is so small that gravitons only hit it sometimes, then it only has mass sometimes and will seem to vanish and reappear to instruments that detect very tiny masses.
These gravitons, according to Starling, are inconcievably tiny and inconcievably numerous. They travel in straight lines at the speed of light and penetrate practically everything without affecting it, passing through the vast empty spaces between subatomic particles like dust through a solar system. When they do hit something solid, they impart their energy to that thing as the property we've been brainwashed into thinking of as mass. As best I can remember, these gravitons are rod-shaped sausages of math and they are identical except for their motions. There were four basic motions, the graviton allegory of earth, air, fire and water. One type moves like an accordion stretching and contracting. Another wobbles like a rubber dog bone shaken in the middle. Another tumbles end over end. The fourth spins on its long axis.
These four "oscillations" combine in pairs to make sixteen other distinct things that are sometimes found to appear and disappear in particle detectors. These sixteen things have names like charm, strange, up, down, dasher, dancer, prancer and I just didn't write them all down, okay? I'll admit to being left utterly behind through most of the hour and taking some comfort in the fact that the guy was dotty. So when I tell you something that Starling said, that doesn't mean that I'm telling you what he said. I'm telling you my best guess about what he said. And you know, although it was a hundred percent .999 fine gobledegook and doubletalk, it didn't seem any more far fetched than the real stuff; and if I had applied myself to homework on this fancy, I might have become conversant in graviton theory the way people become conversant in the fancy of the Tolkein universe.
Imagine a motionless ship becalmed on an endless flat sea. The sea only seems flat to the captain because he doesn't have senses sharp enough or instruments delicate enough to examine the surface closely enough to see that the sea is a raging tumult of an inconcievably large number of inconcievably small waves moving in every direction at once. Since all that energy is hitting the ship from every direction at once, the ship sits still and the captain has no reason to suspect that there might be an inconcievably large number of inconcievably small waves pounding at him from all directions.
One day the "sun" comes "up" and the captain sees there's another ship on this utterly calm sea. By and by the ships drift together and collide even though neither captain can detect any wind or any current. They observe that things floating in the utterly calm sea tend to gather together in clumps and are attracted to each other with a force related to their size. This attraction, this force, they call gravity and attribute it as an internal property of the stuff that floats in the utterly calm sea.
Look again at the two ships as they sit a few yards apart. Each ship blocks some of the submicroscopic waves that would otherwise hit one side of the other ship. Now the forces hitting the ships are no longer equal on all sides. There's a kind of gravity low-pressure area in between the ships and they slide into it and into each other. The closer they get to each other, the more intense the low pressure area is, and they accelerate toward one another. No matter how you position two objects on the utterly calm sea and no matter what initial force you apply to them they are going to seem to have a mutual attraction mathematically related to their distance apart and their size. Put in three objects and the math gets fancier, but the relationships of distance, size and force still hold.
That was Starling's explanation of gravity. We had not found gravitons because we had not looked. We had assumed gravity to be one thing and had not examined this other possibility. Like air pressure, gravitons are only in evidence when there are localized regions of scarcity, and even then the effects can be perfectly interpreted in ways that mask the true nature of the phenomenon.
One of the implications of graviton theory is that there is such a thing as maximum gravity. If you could gather a mass dense enough to block ALL the gravitons coming from one direction, then maximum gravity would be exerted in the opposite direction on the blocked side and could no longer be increased by increasing the mass of the attracted object. Starling said that this maximum gravity is probably going to be found when astrophysicists get together over coffee and ask each other, "Why does this big number keep turning up in our calculations?" He further said that we should not assume that there is enough mass in the universe to stop all the gravitons even in a small space.
At this point, Doctor Starling told a joke about black holes. I didn't then and don't today understand either black holes or the joke well enough to relate it properly. The students laughed politely at what we hoped was the proper moment, and when I glanced at the visiting physicists leaning against the back walls, they grinned and nodded, momentarily flashing the whites of their eyes in a sign held secret among physicists. "We now share a secret," they seemed to be saying.
If I had written this joke down, maybe I would understand it today and share in the secret, but it confused me from premise to punch line. I do remember the punch line, though. If any of you know the rest of the joke, I'd be interested to here it again. So here goes.
Punch line: "If that's the black hole, then what did I just do with my car keys?"
Another implication of Starling's graviton model is that if you could create an area in which there were no gravitons, anything entering that area would have no mass. Yet it's the scarcity of mass created by the blocking of gravitons that describes mass, so the absence of gravitons in a space can represent no mass or maximum gravity, depending on the cause of the region of scarcity.
If you could make gravitons disappear above your head and simultaneously reappear moving at the same speed and direction under your feet, you could suddenly be moving through space without accelerating. Every particle of mass between the disappearing gravitons and the reappearing ones would instantly achieve a velocity without having to build speed and without being subject to the forces of acceleration. A space ship could be made of flimsy stuff and be launched from earth with no more smoke and thunder than a hot air balloon. The astronauts could spend the launch sitting in deck chairs or even standing.
The distribution of gravitons, or if you prefer, the properties of gravity, seem to be very even and constant only because the human race is making all of its observations from the same place; and over most astronomical distances that we've been able to observe across, the distributions of gravitons and their vectors are for all practical purposes even and constant and so gravity still seems to be related to mass only.
But gravitons, like everything in the universe, came into existence at a single spot and spread outward with the rest of the universe like a dumpster full of bb's poured out on a gym floor. So gravitons are relatively thinly spread at the outside of the universe and relatively closely packed toward the center of the universe.
So the universe will keep expanding forever. There are no gravitons "out there" pushing back at the mass, but there are lots of gravitons "in here" pushing stuff out.
That also implies that while gravitons will push masses together, on balance they will push masses apart, especially as they get very far apart and especially as they get way out toward the edge of the universe. Not only will those distant galaxies keep receding into the distance, they will perpetually accelerate until there are no more gravitons behind them pushing. The gravitons push masses together only in local situations, when the edge of the universe is so remote that the scarcity of gravitons there is overwhelmed by the local scarcities.
And so that was that. The lecture ended. Everybody went about their business. I never saw Doctor Starling again, and at the time I didn't think I had even witnessed anything all that unusual.
RTJ -- 10/15/03