Posted on 01/17/2002 4:06:29 PM PST by Ernest_at_the_Beach
In my layman's-level grasp of things (someone more qualified can always clean up my mess later on):
In the quantum scheme of things, a field is a region of space in which some property is altered. In the case of gravity, it's the geometric curvature. In the cases of electricty and magnetism, it's the permittivity and permeability, respectively.
When the object creating the fields is moved, it exchanges virtual particles--"vector bosons" of the force--with the surrounding space so the fields can change. (This gets around spooky "action at a distance" ideas of Newtonian/classical physics.) Virtual particles differ from their real cousins in that they're free. They don't really have to be accounted for in the mass/energy balance sheet of things because their energy is small and they don't exist for long. They're basically quantum hiccups.
Electric and magnetic fields are aspects of the force of electromagnetism; thus the vector boson is the photon. The presumed vector boson of the gravitational force is the graviton. Why it is presumed to propagate at photon speed, I'm not sure, but it probably has to do with relativity theory.
Perhaps its because the Intelligent Designer won't give him a bigger allowance. (It's a slow day.)
What are we talking about here and have you any links?
Yes, but you forgot it has proportionately more mass to accelerate, so it falls at the same rate.
If you do a Google search on "quantized redshift" you will be amazed.
ROFL!!
Oh, I see what you're driving at! OK. Deep breath. Let's see whether I can make this clear.
Imagine that you and I are standing at the end of a long hallway. I'm throwing superballs at you, and you're catching them. Whenever you catch one, you count it.
Our game is fraught with problems, however. One problem is that I throw like a girl. Sometimes I throw things straight up, and sometimes I throw things straight ahead. Another problem is that the ceiling is very sticky. Whenever a superball hits the ceiling, it gets stuck and it never makes it to you. Fortunately, you can move the ceiling up and down.
If you could see the superballs bouncing, you'd notice that they always seem to bounce to certain specific heights. But you can't see the superballs. All you know is how many I throw, how many you catch, and how high the ceiling is.
If the ceiling is too low, none of the balls make it through. That's because no matter how I through the balls, they always bounce to at least a certain height. You move the ceiling a bit higher, and still see nothing. A bit higher, still nothing, and so on, until you put the ceiling high enough to let the least-bouncy balls through.
Suddenly, you are counting a significant number of balls. "OK," you think, "since I believe the balls can have any old energy above the minimum, I expect that there will be some more balls bouncing only a little bit higher than the minimum. I'll raise the ceiling a little bit, and I'll catch a few more of the balls." So you raise the ceiling a bit, but you still see balls coming down the hallway at the same rate. So you raise it a bit more; still you get the same result. So you raise it more and more, and you realize that the rate at which balls make it down the hall has plateaued as a function of ceiling height.
Then you raise it a bit more. Suddenly, the rate of the superballs makes another big jump! This is because you're suddenly admitting the next energy level: the ceiling has been raised higher than the fixed height to which balls of this energy can bounce.
In the case of the experiment (which uses neutrons instead of superballs, a neutron absorber instead of a sticky ceiling, and a neutron detector instead of a fancy West-coast lawyer), they clearly resolve the first jump, the plateau, and the second jump. There is weak evidence for a second and a third plateau, but the finite resolution of the detector washes them out. But I'd say that they have two discrete energy levels firmly in hand.
"through" = throw
Yes. The bouncing neutrons can't have zero energy; there's a minimum energy they can have. You see the population of neutrons having that energy with the first jump. The subsequent plateau tells you that there are no other neutrons with a slightly higher energy.
(It's tempting to think of the plateau as representing the first energy level, but that's wrong; remember, it's a plateau in counting rate, not in energy. The first jump represents the first energy level.)
And if so, what is the second level they've found?
The sudden increase of neutrons after the first plateau represents the sudden acceptance of a second population of neutrons having a higher energy. If these neutrons had not a single energy, but a distribution of energies, you'd see the population slowly ramping up with absorber height after the first plateau, but that isn't what's seen. The counting rate jumps up sharply after the first plateau.
And then finally, when Stockholm calls you, will you get me a ticket to the ceremony?
Stockholm keeps calling me, but I won't accept the call as long as they keep reversing the charges!
That's probably Ingrid. She's 23, single, very lonely, and she gets excited discussing cosmology. I gave her your number.
I suppose it's not, now that I reread it. It's not the clearest piece of science journalism.
I read the paper on www.nature.com (courtesy of Penn's sitewide license). The first plateau is clearly defined on the data plot (which tells you that the jumps up to it and from it are sharp). The second plateau is more of a shoulder.
How thoughtful of you to recall our discussion from many months ago.
You should also recall that I stipulated up front in that discussion that the quantum world was discrete.
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