Doubts in general theory of relativity

In summary: First you need a galilean system of co-ordinates. Then think about a room,inside a man stands.someone pulls the room upwards with a constant force.that man has a ball.he let's go of that ball. A person outside sees this as like this:acceleration is not imparted into the ball,so it is moving uniform.but room is accelerating.so it hits the ground.but observer inside will think that gravitation did this.here you can see that upward acceleration was equavalent to object falling downwards towards the floor.likwise extend this principle to sun and tell me what kind of acceleration is equaval
  • #1
ash64449
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15
according to equvalence principle,acceleration can be equvalent to rest in which gravitational field exists. Earth revolves around the sun as sun produces curvature in space-time. What kind of acceleration is the curvature of space-time produced by sun equavalent too?
 
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  • #2
I think you are seriously messing something up here.
First of all according to GR objects that have mass /energy curve or bend spacetime by themselves even if they are not accelerating just standing there , just like the floor beneath you feels you just as you are standing there or walking upon it.
Now acceleration is a different frame.
Sun produces curvature and Earth does too it's just that Earth has much smaller mass so the curvature is less and it follows to the body with the strongest curvature which near us happens to be the sun.

Now if you think can acceleration create similar force to that of gravity , well yes it can to the observer which is accelerating but only as long as you accelerate if you stop accelerating you don't feel the G force anymore and you become stationary , you are moving only with respect to others in your frame of reference you are not moving.
So the key think here is acceleration both increasing or decreasing in speed.
 
  • #3
Acceleration is equivalent to rest in a gravitational field without tidal effects. If you consider the sun's gravity over a small portion of spacetime where tidal effects are negligible then it is equivalent to acceleration directly away from the sun.
 
  • #4
ash64449 said:
What kind of acceleration is the curvature of space-time produced by sun equavalent too?

It's is equivalent to proper acceleration. The curvature "causes" a coordinate acceleration.
 
  • #5
Crazymechanic said:
Now if you think can acceleration create similar force to that of gravity , well yes it can to the observer which is accelerating but only as long as you accelerate if you stop accelerating you don't feel the G force anymore and you become stationary , you are moving only with respect to others in your frame of reference you are not moving.
So the key think here is acceleration both increasing or decreasing in speed.

well,i was asking precisely this.. I don't understand what you meant by i am seriously missing.. Ok.i didn't understand you answer.. Let me tell question again. Inorder to create an effect of sun's gravity,what kind of acceleration that object should exhibit?
 
  • #6
ash64449 said:
well,i was asking precisely this.. I don't understand what you meant by i am seriously missing.. Ok.i didn't understand you answer.. Let me tell question again. Inorder to create an effect of sun's gravity,what kind of acceleration that object should exhibit?

To me you understand since you put it this way; "equivalent to rest in which gravitational field exists".
 
  • #7
nitsuj said:
It's is equivalent to proper acceleration. The curvature "causes" a coordinate acceleration.

what do you mean by proper acceleration? Is it object accelerating with respect to galiliean system is a straight line? Is this acceleration curvature of space-time caused by sun when stationery equalent too?
 
  • #8
DaleSpam said:
Acceleration is equivalent to rest in a gravitational field without tidal effects. If you consider the sun's gravity over a small portion of spacetime where tidal effects are negligible then it is equivalent to acceleration directly away from the sun.

i actually asked what kind of acceleration equavalent to it.
 
  • #9
nitsuj said:
To me you understand since you put it this way; "equivalent to rest in which gravitational field exists".

no.i was not asking like that.let me use an example. First you need a galilean system of co-ordinates. Then think about a room,inside a man stands.someone pulls the room upwards with a constant force.that man has a ball.he let's go of that ball. A person outside sees this as like this:acceleration is not imparted into the ball,so it is moving uniform.but room is accelerating.so it hits the ground.but observer inside will think that gravitation did this.here you can see that upward acceleration was equavalent to object falling downwards towards the floor.likwise extend this principle to sun and tell me what kind of acceleration is equavalent to sun's gravity on earth?
 
  • #10
nitsuj said:
To me you understand since you put it this way; "equivalent to rest in which gravitational field exists".

by that i actually meant that sun is able to curve space-time when it is stationery.
 
  • #11
ash64449 said:
well,i was asking precisely this.. I don't understand what you meant by i am seriously missing.. Ok.i didn't understand you answer.. Let me tell question again. Inorder to create an effect of sun's gravity,what kind of acceleration that object should exhibit?

Dalespam answered this in #3: straight outwards, away from the sun.
 
  • #12
Nugatory said:
Dalespam answered this in #3: straight outwards, away from the sun.

No friend,i know that! But i don't know What kind of acceleration. I want that... I mean directional acceleration or straight line acceleration.. like that.. You can understand what exactly i was saying if you read #9..
 
  • #13
Nugatory said:
Dalespam answered this in #3: straight outwards, away from the sun.

Oh! Sorry friend,i haven't seen that part of comment as i was reading from the mobile. What does that mean away from the sun?? Can you explain a little easy manner. Away from what?
 
  • #14
ash64449 said:
Oh! Sorry friend,i haven't seen that part of comment as i was reading from the mobile. What does that mean away from the sun?? Can you explain a little easy manner. Away from what?

Radially outwards, away from the center of the sun, in any direction. If you were standing on the surface of the sun (bad idea, of course - it's hot) the direction would be "up"
 
  • #15
ash64449, your question is very confusingly worded. You are confusing yourself as much as you are confusing all of the rest of us. Let's just skip your question and instead just explain how the equivalence principle works.

Suppose that you have a UNIFORM gravitational field, meaning that there are no tidal effects present in the gravitational field. That type of gravitational field is experimentally equivalent to an accelerating reference frame without gravity.

For a person in a small room on the surface of the Earth the gravity of the Earth is approximately uniform, so you can say that experiments conducted in this room will produce the same results as though he were in a rocket ship accelerating at 1 g far from any gravitating masses.

For a short period of time in the Earth's orbit the gravity of the sun is approximately uniform, but the Earth's gravity is not uniform, so it is difficult to treat that situation using the equivalence principle.

However, consider a related example of a small spaceship orbiting the sun at 1 AU. Inside the spaceship for a short period of time the gravity of the sun is approximately uniform and the spaceship's gravity is negligible, so you can use the equivalence principle. By the equivalence principle, being in free-fall in a uniform field is equivalent to being in an inertial frame far from any gravitating body, so you can say that experiments conducted in this spaceship will produce the same results as though he were far from any gravitating masses.
 
  • #16
Nugatory said:
Radially outwards, away from the center of the sun, in any direction. If you were standing on the surface of the sun (bad idea, of course - it's hot) the direction would be "up"

oh.. Thank you friend.. similar to what i said in #9... Thank you once again!:smile:
 
  • #17
DaleSpam said:
Suppose that you have a UNIFORM gravitational field, meaning that there are no tidal effects present in the gravitational field. That type of gravitational field is experimentally equivalent to an accelerating reference frame without gravity.

Yes.This is what i was saying.. am i not fluent or you guys cannot understand what i said... Watch #9 in which i explain equivalence principle.
i just asked this: Sun has a curved Gravitational field.So Which accelerating reference frame without gravity is equivalent to the Sun's curved Gravitational field?? That is what i was asking. I got the answer...
 
  • #18
ash64449 said:
Which accelerating reference frame without gravity is equivalent to the Sun's curved Gravitational field?? That is what i was asking. I got the answer...
And what was the answer? (in your own words)
 
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  • #19
DaleSpam said:
And what was the answer? (in your own words)


acceleration directly away from the sun.
 
  • #20
DaleSpam said:
And what was the answer? (in your own words)

just like that if you were standing in the sun,direction is towards the up
 

Related to Doubts in general theory of relativity

1. What is the general theory of relativity?

The general theory of relativity is a theory of gravitation developed by Albert Einstein in 1915. It is a geometric theory that explains the force of gravity as the curvature of spacetime caused by the presence of mass and energy.

2. How is the general theory of relativity different from Newton's theory of gravitation?

The general theory of relativity is a more comprehensive and accurate theory of gravitation compared to Newton's theory. It takes into account the effects of acceleration, time dilation, and the curvature of spacetime, whereas Newton's theory only considers the force of gravity as an attractive force between masses.

3. What evidence supports the general theory of relativity?

Several experimental and observational tests have been conducted to support the general theory of relativity. These include the bending of light by massive objects, the precession of Mercury's orbit, and the gravitational redshift of light. Additionally, the predictions of the theory have been confirmed by numerous experiments, such as the Pound-Rebka experiment and the Hulse-Taylor binary pulsar system.

4. Can the general theory of relativity be unified with quantum mechanics?

Currently, there is no unified theory that combines general relativity with quantum mechanics. This is a major challenge in physics and is an area of ongoing research. Some theories, such as string theory and loop quantum gravity, attempt to reconcile these two theories, but they have not been conclusively proven.

5. Are there any limitations to the general theory of relativity?

While the general theory of relativity has been incredibly successful in explaining and predicting many phenomena, it does have some limitations. For example, it breaks down in extreme situations, such as at the singularity of a black hole or during the initial moments of the universe's creation. Additionally, it does not account for the other fundamental forces of nature, such as the strong and weak nuclear forces.

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