Is gravity a fictitious force? Why or why not?

>visual evidence in the fucking sky
>fictitious

ummmm what?

>>8651939
You're literally right now in the fucking ground because of a force, how can you say that force is fictitious?

>>8651969
centripetal force is an example of ficititicous force that we can feel, observe, and even measure but this force is not a force in a classical sense.

>>8651973
Yeah, a fictitious force is a force that arise from not using an inertial frame of reference. Gravity is not a factitious force.

Firstly, don't be a physical realist. This solves most of those fake problems. There are phenomena in the world and there are theories. There are words representing features of such frameworks, and those are used to describe the observable phenomena. But the physical quantities don't correspond to anything "real" - nothing that's as much of a give that there can't be another more exact physical theory in which that notion isn't part of.

That being said, with your question of "fictitious force", there are two frameworks at hand. The Newtonian one in with you assume a gravitational force field with infinite information propagation* and the general theory of relativity, where gravitation can be Incorporated in the mathematical framework of (Pseudo-)Riemannian geometry.

*With Newton, you have a gravitational force field that goes like 1/|r0-r|^2, where r0 is the position of some mass and r is the distance. If r0=0 and r=10^9001 miles, then there is a tiny force field of strength
F = 1/(10^9001)^2
(times some constants) exerted on some mass in distance r. Now if you move the mass at r0 a millimeter away from the other, then the tiny force becomes
1/(10^9001+1mm)^2 < F.
Instantaneously, the movement of the mass at r0 affects the force exerted far far far away.
This breaks with Special Relativity and the speed of light as limit for information propagation.

In general relativity, a formula with 1/|r0-r|^2 is not what describes gravity on the fundamental level. Instead, gravity is made aspect of space(time) itself.
You gotta learn Pseudo-Riemann geometry to get an intuition for why curvature in certain mathematical spaces provides behavior of free motion that resembles something like 1/|r0-r|^2 ... that's what amounts to learning General relativity.

>>8651991
Can you elaborate your answer?

File: money_rain.jpg (205KB, 962x635px) Image search: [Google]

205KB, 962x635px

(cont.)

For practical purposes, a inertial coordinate system one where stars don't appear to move, in a small enough time interval.

A fictitious force is a functional expression for a force in some cooridnate system, that when translated to an inertial system vanishes.
In Newtonian gravity, you can't make 1/|r0-r|^2 disappear by moving to an inertial system.
** What you can do is locally make a cooridnate transformation into a globally accelerated system so that the acceleration is gone. That globally accelerated system is not inertial, however.

In general relatvitiy, there is no 1/|r0-r|^2 you'd need to transform away. There's not "force" like with Newton at all. However, the effect of two masses left alone slowly approaching each other is still there of course, but it's implemented, in the Einsteinian framework, in a geometric fashion.
You can always go into a locally flat system ... that amounts to ** in Newtonian gravity.

>>8651969
It's fictitious because we are living in a simulation. Nothing is real

>>8651996
Basically fictitious forces arise from rotation or acceleration of a frame of reference, look up the five term acceleration formula.

>>8652021

Let's do a thought experiment then. We are on Einstein's moving space elevator at the rate of the speed of gravity throughout space. Einstein argues that the individual in this frame of reference will never be able to concretely determine whether he is stationary under the effects of gravity on Earth, or just simply in an accelerating space elevator at the rate of gravity. This leads to the argument that gravity is a fictitious force in a sense that the *actual* force is acceleration via the curvature of space-time.


If this is incorrect (which I am open to it being), then what force is it in fact that would be applied to someone dropping a ball inside the ascending space elevator? The ball would fall to the ground at the same rate, under the guise of gravity. One cannot know whether this is actually gravity or just acceleration through spacetime.

I disagree with your initial frame of reference, as matter itself in the universe is what the acceleration is acting in reference towards.


Similarly, let's imagine we have water inside of a bucket tied to a string hanging from a post. Lets say we rotate the bucket itself in a continuous circle. The water stays level and motionless for a slight period of time, until friction caused by the bucket will cause the water to become concave in shape in the center. After the pail stops, the water will still continue to spin. This demonstrates the force applied to the water is not in respect to the pail at all.

>>8651969
hes talking about GOD.