Infinite gravity

[awaterpon]

I post a thread here in speculation proposing that gravity has a limited range I would like to ask some questions about the existing fact.

My questions are :

What does science think of infinite gravity " gravity being everywhere" ?

How it is mathematically described "giving the idea that Newtonian gravitational law doesn't work for infinity distance" ?

Is the idea of infinite gravity part of GR ? how it is described according to GR?

Is there a proof for gravity being infinite in range ?

Thanks,

 

 

Edited May 2, 2019 by awaterpon

[Strange]

21 minutes ago, awaterpon said:

What does science think of infinite gravity " gravity being everywhere" ?

As there is mass-energy everywhere, there must be gravity everywhere.

21 minutes ago, awaterpon said:

How it is mathematically described "giving the idea that Newtonian gravitational law doesn't work for infinity distance" ?

No mathematical equation works for infinity. Because infinity is not a number you can put in the equation. We can only describe what happens as you approach infinity.

21 minutes ago, awaterpon said:

Is the idea of infinite gravity part of GR ? how it is described according to GR?

What do you mean by "infinite gravity"?

If you mean gravity having infinite range, then yes, that is part of GR (because in the limit, it is the same as Newtonian gravity).

21 minutes ago, awaterpon said:

Is there a proof for gravity being infinite in range ?

There isn't really "proof" of anything in physics.

What we do is create models and test them. The two models of gravity we have (Newtonian and GR) are both supported by evidence. That is all we can say.

[michel123456]

48 minutes ago, awaterpon said:

What does science think of infinite gravity " gravity being everywhere" ?

I suspect it is about the Horizon Problem.

(Sorry I haven't read the 6pages of your other thread).

[Strange]

8 minutes ago, michel123456 said:

I suspect it is about the Horizon Problem.

(Sorry I haven't read the 6pages of your other thread).

That did get mentioned in the other thread.

[swansont]

2 hours ago, awaterpon said:

I post a thread here in speculation proposing that gravity has a limited range I would like to ask some questions about the existing fact.

My questions are :

What does science think of infinite gravity " gravity being everywhere" ?

Gravity propagates at the speed of light. If we can see it, gravity must exist there.

2 hours ago, awaterpon said:

How it is mathematically described "giving the idea that Newtonian gravitational law doesn't work for infinity distance" ?

Newtonian gravity doesn't limit the propagation speed, so it is valid for all distances, even as one approaches infinity. However, we know that Newtonian gravity is a flawed model, and this is one of the flaws.

2 hours ago, awaterpon said:

Is the idea of infinite gravity part of GR ? how it is described according to GR?

As you have been told approximately 47 million times now, in GR gravity propagates at the speed of light. Tp see how this is described in GR you would have to study the physics.

2 hours ago, awaterpon said:

Is there a proof for gravity being infinite in range ?

All tests of gravity are consistent with the GR model, so we have a lot of confidence that the model is correct.

[awaterpon]

1 hour ago, swansont said:

All tests of gravity are consistent with the GR model, so we have a lot of confidence that the model is correct.

Not gravity in general but the fact that it should be infinite,  how physics determines it should be infinite ?

[Strange]

1 minute ago, awaterpon said:

Not gravity in general but the fact that it should be infinite,  how physics determines it should be infinite ?

You don't seem to understand how science works. Here is a summary:

1. Develop a mathematical model to describe what we observe

2. Make quantifiable and testable predictions based on that model

3. Test those predictions by means of observation/experiment

The infinite reach of gravity is not testable.

However, many other aspects of the model (GR) have been tested and are consistent with the model. That is all we can say.

[awaterpon]

7 minutes ago, Strange said:

You don't seem to understand how science works. Here is a summary:

1. Develop a mathematical model to describe what we observe

2. Make quantifiable and testable predictions based on that model

3. Test those predictions by means of observation/experiment

The infinite reach of gravity is not testable.

 

Neither of these is applied to the fact that gravity is infinite then no one can scientifically say gravity is infinite.

Edited May 2, 2019 by awaterpon

[studiot]

3 hours ago, awaterpon said:

I post a thread here in speculation proposing that gravity has a limited range

And in that thread I asked you a simple geometric question you failed to reply to.

Last time the question was posted in terms of velocity and dynamics.

But the geometric difficulties remain in statics.

I take it you will agree three things, which are all straight forwardly observed in Newtons gravity.

1) That for any body the greater the body the greater the body's gravitational effect on other bodies.

2) That if body A affects body B then body B affects body A.

3) That the influence of body A affects every part of body B.

 

You have added the proposal that there is some fixed finite range for the gravitational effect of a body.

So how does this range vary with distance from the body?
Does the range increase with body mass size, like the force effect in rule 1?

If so then my fig 1 shows how two bodies of different sizes break rule 2.
That is for A >B, body B can be inside the radius of inference of A, whilst body A remains outside the radius of influence of B.

Further fig 2 shows where the range of Body A passesnthrough body B dividing it into 2 zones.

So how do you treat this?

What mass do you use in the calculation?

Does the gravitational effect of body A extend beyond its range into the shaded parts of body B?

 

[Strange]

9 minutes ago, awaterpon said:

Neither of these is applied to the fact that gravity is infinite then no one can scientifically say gravity is infinite.

We have a scientific theory in which gravity has unlimited range.

If you want to come up with an alternative mathematical model where that is not the case, but which is still consistent with all other evidence, then go ahead. 

You will also need to describe how your limited range of gravity can be tested by experiment or observation. 

[swansont]

1 hour ago, awaterpon said:

Not gravity in general but the fact that it should be infinite,  how physics determines it should be infinite ?

That's what the theory says. 

In general, gravity being 1/r^2 is a requirement for there to be stable, closed orbits, which is what we have (i.e. this is observed). It's the form that is equivalent to Kepler's laws of orbital motion, which are what we observe to be true. And it works to get our space missions where we want them to go (as long as the units are correct). Gravity having a potentially infinite reach is an implication of having that form factor.

Most physics has that kind of formulation — be it a power law or an exponential.  Having effects which simply cut off at some arbitrary value is not the norm. The best you usually do is have that exponential which rapidly becomes weak, to the point where it can be ignored, but never actually disappears. These are concepts you would recognize if you studied physics and learned the basics.

 

 

[Airbrush]

Does the most distant quasar observed have gravity that reaches us, but the force is miniscule?

Edited May 2, 2019 by Airbrush

[Ghideon]

5 minutes ago, Airbrush said:

Does the most distant quasar observed have gravity that reaches us, but the force is miniscule?

Yes that sounds correct. Note that you seems to ask about a static situation but the universe is not:

In the past the matter in the quasar was much closer to us.
Waves from gravitational events, such as black hole mergers, in the distant quasar may or may not have reached us yet.

[swansont]

34 minutes ago, Airbrush said:

Does the most distant quasar observed have gravity that reaches us, but the force is miniscule?

If we can see it, its gravity has had time to reach us.  

 

[michel123456]

21 hours ago, swansont said:

If we can see it, its gravity has had time to reach us.

Afraid to feed the animal but: if gravity was faster than C, how could you notice? Would it be measurable since the faster thing we can observe is restricted by C?

[swansont]

1 hour ago, michel123456 said:

Afraid to feed the animal but: if gravity was faster than C, how could you notice? Would it be measurable since the faster thing we can observe is restricted by C?

Gravitational waves would arrive before light from events that emit both. For events where there is acceleration, the source is where the mass was at the time of the event, not where it is after the signal reaches you (the vector points to where it was, not where it is). This direction would differ if gravity propagated at a speed other than c.

[Strange]

1 hour ago, michel123456 said:

Afraid to feed the animal but: if gravity was faster than C, how could you notice? Would it be measurable since the faster thing we can observe is restricted by C?

If the speed of gravity were different then there would be other measurable difference in GR. There are various direct and indirect ways of measuring the speed of gravity: https://en.wikipedia.org/wiki/Speed_of_gravity#Measurements

These are all consistent with the speed being the speed of light.

And there is nothing that says we can't measure things faster than the speed of light. There was the famous example where it was thought that neutrinos were faster than light.

[Airbrush]

On 5/2/2019 at 7:40 AM, swansont said:

If we can see it, its gravity has had time to reach us. 

And even before we can see it, the gravity from that region would have reached us before the quasar even formed.

Would all matter in the universe already be in "gravitational contact" with all other matter in the universe, ever since the beginning?  Since the gravity waves began propagating shortly after the big bang.

 

[Strange]

1 minute ago, Airbrush said:

Would all matter in the universe already be in "gravitational contact" with all other matter in the universe, ever since the beginning?  Since the gravity waves began propagating shortly after the big bang.

Yes. See Michael123456's post on the Horizon Problem. (This doesn't really have anything to do with gravitational waves though [and nothing to do with "gravity waves", which are a completely different thing  ])

[Hamster22]

On 5/2/2019 at 1:38 PM, awaterpon said:

I post a thread here in speculation proposing that gravity has a limited range I would like to ask some questions about the existing fact.

I like your thoughts about a limited range of gravity. I think you are right. This is logical and reasonable. If matter has the limiting energy mc ^ 2, this means that a radius of action of gravity cannot be infinite. I also develop a theory of a limited range of gravity and even got the formula that approximately calculates the maximum radius of action of the gravity of a space object by its gravitational parameter. I hope soon to publish some of  details of this theory. I am pleased that I am not alone in my ideas. Thank.

 

[Sensei]

2 hours ago, Hamster22 said:

If matter has the limiting energy mc ^ 2,

E=mc^2 simply informs how to convert from mass units (e.g. kg or eV/c^2) to energy units (e.g. J or eV)..

In normalized units (where c=1) you simply have E=m.

 

[Strange]

2 hours ago, Hamster22 said:

If matter has the limiting energy mc ^ 2, this means that a radius of action of gravity cannot be infinite.

Apart from the fact you don't appear to understand mass-energy equivalence, this does not imply a limited range for gravity.

2 hours ago, Hamster22 said:

I hope soon to publish some of  details of this theory.

Please let us know which peer-reviewed journal it is published in.

[zapatos]

On 5/3/2019 at 4:10 PM, Strange said:

Yes. See Michael123456's post on the Horizon Problem. (This doesn't really have anything to do with gravitational waves though [and nothing to do with "gravity waves", which are a completely different thing  ])

This would seem to imply that objects beyond the observable universe may be 'observable' by their gravity. Does that sound right?

[Strange]

10 minutes ago, zapatos said:

This would seem to imply that objects beyond the observable universe may be 'observable' by their gravity. Does that sound right?

Not sure why you think it would imply that. The horizon problem is about the fact that the observable universe is so homogeneous (e.g. the CMB is exactly the same temperature everywhere) that it there must have been time for it to reach equilibrium even though the transfer of information/temperature/etc. is limited by the speed of light. To be that compact, but to have reached the size it is now, requires inflation to account for the rapid expansion (or some other explanation for the uniformity).

So light could travel across the entire observable universe in a short time. And so could gravity. But this does not allow us to see beyond the observable universe. And it does not allow gravity from beyond the observable universe to reach us.

[zapatos]

1 hour ago, Strange said:

Not sure why you think it would imply that.

I was referring to the other part of the conversation.

Airbrush asked "Would all matter in the universe already be in "gravitational contact" with all other matter in the universe, ever since the beginning?"

You responded "yes".

If that is the case, then doesn't that imply that we are in gravitational contact  with objects outside the observable universe? And hence able to observe them via their gravitational impact?