Is Gravity a Force? Debate & Questions

  • Thread starter Thread starter spidey
  • Start date Start date
  • Tags Tags
    Force Gravity
spidey
Messages
213
Reaction score
0
Is gravity a force?
if its not a force as per GR,then why it is included in the fundamental forces and how we can combine remaining three forces with gravity(not a force)?
if gravity is a force,why we are following GR which says gravity isn't a force?
 
Physics news on Phys.org
It's a force in Newton's theory. It's not a force in GR. No matter what theory we use to describe it, it's definitely an interaction. So we should be talking about the fundamental interactions, not the fundamental forces.
 
Gravity is just as much a force as the other three...sure, it has some different characteristics since it acts on everything, even spacetime, while the other forces are more limited...

Nobody has figured out how to combine all four forces but superstring theory is trying...likely a new perspective, some different fundamental insights are required...like those that got relativity and quantum theory underway...
 
Is it possible to combine other three forces with gravity even though gravity isn't a force? then this would be equivalent to finding Ether which doesn't exists? i mean, we are trying to find a solution for an invalid question?
 
it is a separate fundamental "interaction" in the sense that the curvature of space (which is related to the acceleration due to the force of gravity in a Newtonian sense) is caused by the presence of matter (and energy when you divide by c2). so if you don't want to say that some matter is exerting a force on some other matter, you can say that some matter is warping or curving space-time which causes (from the Euclidian POV) inertial or free-falling trajectories to bend. at least that's how i think of the interaction of gravity.
 
spidey said:
Is it possible to combine other three forces with gravity even though gravity isn't a force?

None of them are forces. Not in the F=ma sense of freshman physics. Quantum mechanics, the realm of the "other three forces" is not a theory of force. It is a theory of superposition and strength of interaction. Newtonian "forces" are the macroscopic limit of field interactions. This phrase "four fundamental forces" is an oversimplification.
 
OK, so this has bugged me for a while about the equivalence principle and the black hole information paradox. If black holes "evaporate" via Hawking radiation, then they cannot exist forever. So, from my external perspective, watching the person fall in, they slow down, freeze, and redshift to "nothing," but never cross the event horizon. Does the equivalence principle say my perspective is valid? If it does, is it possible that that person really never crossed the event horizon? The...
In this video I can see a person walking around lines of curvature on a sphere with an arrow strapped to his waist. His task is to keep the arrow pointed in the same direction How does he do this ? Does he use a reference point like the stars? (that only move very slowly) If that is how he keeps the arrow pointing in the same direction, is that equivalent to saying that he orients the arrow wrt the 3d space that the sphere is embedded in? So ,although one refers to intrinsic curvature...
ASSUMPTIONS 1. Two identical clocks A and B in the same inertial frame are stationary relative to each other a fixed distance L apart. Time passes at the same rate for both. 2. Both clocks are able to send/receive light signals and to write/read the send/receive times into signals. 3. The speed of light is anisotropic. METHOD 1. At time t[A1] and time t[B1], clock A sends a light signal to clock B. The clock B time is unknown to A. 2. Clock B receives the signal from A at time t[B2] and...
Back
Top