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Re: [Phys-l] definition of gravity



Out of my comfort zone too, but I assume that gravitons would be associated only with the nonextensibility of freely falling frames which is the result of spacetime cruvature in GR and is the only REAL effect of the physical phenomenon that we call "gravitation."

John Mallinckrodt
Cal Poly Pomona

On Nov 8, 2011, at 8:29 AM, Edmiston, Mike wrote:

I'm way out of my comfort zone here, so I might be asking a dumb question. What if it turns out that gravitons exist, and the force we commonly associate with Newton's Law of Gravity (Gm1m2/r^2) is mediated by gravitons. Does a strict adherence to "equivalence" mean that gravitons would also necessarily be involved in the observed forces John Mallinckrodt is speaking of in his two questions (below)?

If gravitons are involved in F= Gm1m2/r^2, but not involved in F=ma, then it seems we would have a problem saying that the rocket-generated force is a "gravitational force."

So what is the current thinking about gravitons and how they fit into the equivalence principle?


Michael D. Edmiston, PhD.
Professor of Chemistry and Physics
Chair, Division of Natural and Applied Sciences
Bluffton University
Bluffton, OH 45817
Office 419-358-3270
Cell 419-230-9657


-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of John Mallinckrodt
Sent: Tuesday, November 08, 2011 10:37 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] definition of gravity

You are in a rocket whose motors are producing precisely enough thrust to cause it to accelerate at 9.8 m/s^2. You are standing on a scale on the floor that reads the same weight that it does when used on the surface of the Earth.

Question 1: Does anyone have any qualms whatsoever about calling what you are experiencing a gravitational force that is every bit as "real" as any gravitational force can possibly be?

Question 2: Does anyone have any qualms whatsoever about saying that you find there to be a gravitational field of 9.8 N/kg directed toward the floor of the rocket?

John Mallinckrodt
Cal Poly Pomona
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