Is Gravity Really a Pseudo-Force in Modern Physics?

[PhilosophyofPhysics]

I was reading a Feynman lecture and I believe he said something about pseudo-forces being proportional to the masses and that gravity could be one. Then I think he said that in GR gravity is like a pseudo-force. Is gravity considered as a pseudo-force if the geometry of spacetime is its cause?

Are any of the new theories of quantum gravity working on a quantum geometry and not including actual "gravity particles" like gravitons?

 

[john baez]

I was reading a Feynman lecture and I believe he said something about pseudo-forces being proportional to the masses and that gravity could be one. Then I think he said that in GR gravity is like a pseudo-force. Is gravity considered as a pseudo-force if the geometry of spacetime is its cause?

Yes, that's a popular viewpoint on general relativity. Of course, gravity arises from how energy and momentum curve spacetime, and it's a very real thing, so one shouldn't infer from the term "pseudo-force" that gravity is somehow "fake". But, it's not a force in the sense of something which causes particles to accelerate - particles move along geodesics, "as straight as possible".

Are any of the new theories of quantum gravity working on a quantum geometry and not including actual "gravity particles" like gravitons?

Sure! The closely related ideas called "loop quantum gravity" and "spin foam models" are all the result of people trying to develop a theory of quantum geometry. Try these for starters:

Institute for Gravitational Physics and Geometry, http://www.gravity.psu.edu/research/poparticle.shtml"

Carlo Rovelli, http://relativity.livingreviews.org/Articles/lrr-1998-1/"

John Baez, This Week's Finds in Mathematical Physics:
http://math.ucr.edu/home/baez/week109.html" .

 

[Entropia]

There is ongoing debate and research in the scientific community about the nature of gravity and whether it can be considered a pseudo-force. Pseudo-forces are defined as apparent forces that arise due to the acceleration of a reference frame, rather than being caused by physical interactions between objects. In this sense, gravity could be considered a pseudo-force, as it is a result of the curvature of spacetime rather than a direct interaction between masses.

However, this interpretation of gravity as a pseudo-force is not universally accepted. In general relativity, gravity is described as a fundamental interaction, and the curvature of spacetime is seen as the cause of this force rather than a mere effect. Additionally, the concept of gravitons, which are hypothetical particles that mediate the gravitational force, is still being explored and investigated in the field of quantum gravity.

Some theories of quantum gravity, such as loop quantum gravity, do involve a quantum description of the geometry of spacetime rather than a particle-based approach. However, these theories are still in the early stages of development and it is not yet clear if they will ultimately be successful in fully explaining gravity.

In conclusion, while there are different perspectives on the nature of gravity and its classification as a pseudo-force, the current understanding is that gravity is a fundamental force that arises from the curvature of spacetime. Further research and experimentation will continue to deepen our understanding of this fundamental force and its role in the universe.