Physicists Clarify Exotic Force

Azazel writes "A research group, including Purdue University physicist Ephraim Fischbach, has completed an experiment which shows that gravity behaves exactly as Isaac Newton predicted, even at small scales. Unfortunately for those in search of the so-called "Theory of Everything," the finding would seem to rule out the exceptions to his time-honored theories that physicists believe might occur when objects are tiny enough."

Comments

Gravity at small length scales

[dr. loser]

IAAP (I am a physicist), and here's the deal:

There are suggestions out there that one way to test for the existence of extra "compactified" spatial dimensions (the kind of stuff needed in string theories) is to look for deviations from Newton's 1/r^2 gravity at small distance scales. See, for example, here.

The problem is, it's very hard to measure just the gravitational interaction between two objects separated at micron scales. Gravity is incredibly weak compared to common forces like electrostatics and magnetic interactions, and even more exotic things like Casimir forces (related to the van der Waals interaction).

The Purdue team has shown that the measured Casimir force in their experiment acts just as expected, setting a new limit on how screwy gravity can be at these distance scales.

For what it's worth, there are two other big efforts in this area. The one at Stanford is led by Aharon Kapitulnik, and is so sensitive that their apparatus can detect the different forces on Au and Si in the earth's magnetic field due to diamagnetism (!). The one at Washington is reportedly even more sensitive, and there are rumors circulating that they may have seen something exciting.

The really cool thing here is how table-top solid state experiments may have something profound to say about high energy physics, without any big accelerators.

Re:What?

[jd]

Let's start with the easy one: Is space/time quantized? To test this, you must point a telescope at a great enough distance that the angle produced by the increment is clearly visible and clearly uniform. Have telescopes seen clearly visible and "unnaturally" uniform regions of space? Uh, yes. That's exactly what is seen in the early Universe, despite the obvious problems this would create (such as no way for structures to form). The solution to this problem is to say that we are seeing a small enough region of quantized space that variation is impossible, that we are not seeing the variation that must exist because we aren't looking at a continuun. Ergo, yes, we have observations that can best be explained by quantized space/time.

Now onto the rest of my post: The physicists at Warwick University, for the Einstein Celebration, considered my theories on relativity to actually be pretty good. :) I had produced a summary of the derivation of relativity and from that derived what overall physical phenomena must underpin the entire theory.

The quantization of space/time is guaranteed. Why? Because matter is quantized, and matter and energy are simply different facets of the same thing, energy must be quantized. (Matter is merely condensed energy, it is therefore the same stuff, just in a different state.)

If energy is quantized, then fields must be quantized, as fields define energy. If fields are quantized, then space and time are quantized, as fields are defined over these.

The scale of quantization is extremely small. A Higg's Particle is the smallest unit of matter definable, but in order to have energy to condense, the scale on which a photon itself exists must be smaller still. There may well be smaller particles in the "quantum foam", which is fine as they don't have to be stable. The Higg's Particle is stable and is likely the smallest object that can be stable.

What does that give us for scale, though? Without knowing even the theoretical mass of the Higg's Particle, that is hard to even guess at, but a guesstimate based on existing data would imply quantization of space at around about 10^-50 m, and something comparable for time.

No, you do not perceive gravity as a point source, because you are not a point. That is why objects in a gravity well will stretch. EACH point of you will experience gravity differently and not from "one source" but rather from the composite value.

(If you are between Earth and the moon, you will experience gravity from each. At the right point, you will be held stationary because the interference will produce no net force. If that were not the case, the Universe would be in serious trouble. As would most of physics, as a lot depends on overlapping fields.)

We are talking about energy differentials. It is a grave mistake of the first order to distinguish between phenomena that are, in fact, the same thing. All objects travel at the speed of light, at different angles to space/time. It is the angle that produces relativistic mass, reliativistic length and relativistic time.

This can be proved by simple trigonometry, and is likely where Einstein got the equations in the first place. Relativity is just a restating of Pythagoras, as all equations are based on the same formula: R' = sqrt(1 - v^2/c^2), where R' is the relativistic version of the variable of interest.

When re-written, this becomes R'^2 + V^2 = C^2, which is basically Pythagoras.

However, the consequence of this is both simple and profound. If all objects indeed travel at the speed of light, at different angles to space/time, and indeed relativity is nothing more than the projection onto the plane of interest, then gravity is a direct consequence of this motion through space/time.

(Relativistic mass, by this logic, is simply a force exerted at 90' to space. The distortion of space is the result of this. This means tha