Gravity (Hijack from What other field affect light like gravitational fields?)

[Itoero]

A gravitational field is a model that explains a lot regarding gravitational phenomena but such a field has never been proven.

[swansont]

16 minutes ago, Itoero said:

A gravitational field is a model that explains a lot regarding gravitational phenomena but such a field has never been proven.

Um, what? 

[Itoero]

2 hours ago, swansont said:

Um, what? 

 Quantum theory can't explain gravity. A gravitational field implies how we currently understand gravity, it belongs to the world of science but it doesn't concern scientific evidence.

[Strange]

26 minutes ago, Itoero said:

 Quantum theory can't explain gravity. A gravitational field implies how we currently understand gravity, it belongs to the world of science but it doesn't concern scientific evidence.

Of course if "concerns scientific evidence". Are you trying to say that there is no evidence for GR?

If you just mean that we don't know if space-time "exists" or the theory represents "reality" then that is true of all science. And is completely irrelevant.

[StringJunky]

44 minutes ago, Itoero said:

 Quantum theory can't explain gravity. A gravitational field implies how we currently understand gravity, it belongs to the world of science but it doesn't concern scientific evidence.

The scientific evidence is that the model conforms to the measurements and a gravitational field does that.

Edited August 21, 2018 by StringJunky

[beecee]

1 hour ago, Itoero said:

 Quantum theory can't explain gravity. A gravitational field implies how we currently understand gravity, it belongs to the world of science but it doesn't concern scientific evidence.

 

4 hours ago, Itoero said:

A gravitational field is a model that explains a lot regarding gravitational phenomena but such a field has never been proven.

The model is GR which incorporates spacetime, which when affected [curved, warped, twisted etc] by mass, exhibits what we call gravity. The Lense Thirring Effect, gravitational lensing, gravitational waves, all verify the spacetime/gravity model. And of course you err in asking for proof for obvious reasons.

[Strange]

1 hour ago, Itoero said:

Quantum theory can't explain gravity.

It is not expected to.

The theory of evolution doesn't explain how to bake a great chocolate cake.

[swansont]

17 hours ago, Itoero said:

 Quantum theory can't explain gravity. A gravitational field implies how we currently understand gravity, it belongs to the world of science but it doesn't concern scientific evidence.

Quantum theory can’t explain evolution, either. 

Gravity doesn’t concern evidence? Are you joking?

[Itoero]

3 hours ago, swansont said:

Quantum theory can’t explain evolution, either. 

Gravity doesn’t concern evidence? Are you joking?

Not Gravity, the existence of a gravitational field is not scientifically proven. The evidence for gravitational field is based on mathematical logic.

We don't know enough about gravity to assume there is a gravitational field.  The fact that we can't explain star-dynamics (dark matter) shows our understanding of gravity lacks to know there is a gravitational field.

A while back someone created a new Gravity theory.

"In 2010, Erik Verlinde surprised the world with a completely new theory of gravity. According to Verlinde, gravity is not a fundamental force of nature, but an emergent phenomenon. In the same way that temperature arises from the movement of microscopic particles, gravity emerges from the changes of fundamental bits of information, stored in the very structure of spacetime."https://phys.org/news/2016-11-theory-gravity-dark.html
 

 

[Strange]

3 minutes ago, Itoero said:

Not Gravity, the existence of a gravitational field is not scientifically proven. The evidence for gravitational field is based on mathematical logic.

Mathematics and evidence.

But exactly the same is true of the electromagnetic field. Or quarks. Or even atoms.

3 minutes ago, Itoero said:

A while back someone created a new Gravity theory.

And exactly the same will true of that (if there is ever any evidence for it).

You seem to prefer a mathematical model for which there is no evidence over one for which there is a large amount of evidence. Why is that?

3 minutes ago, Itoero said:

We don't know enough about gravity to assume there is a gravitational field. 

All the evidence s consistent with the model. That is all you ever say in science.

4 minutes ago, Itoero said:

The fact that we can't explain star-dynamics (dark matter) shows our understanding of gravity lacks to know there is a gravitational field.

It may show that. But theories based on that idea haven't worked so far. So the overwhelming evidence is that it is matter.

Edited August 22, 2018 by Strange

[Itoero]

Stop misinterpreting me. I don't prefer a mathematical model. I only stated there is an other theory about Gravity. It's not a mathematical model and it does not debunk current evidence.

[Achilles]

I think you mean gravitons is not scientifically proven. The gravitational field is well established. I think you maybe have to much time watching happy feet and playing with yourself instead of learning English in Belgium.

[Itoero]

34 minutes ago, Achilles said:

I think you mean gravitons is not scientifically proven. The gravitational field is well established. I think you maybe have to much time watching happy feet and playing with yourself instead of learning English in Belgium.

No I don't mean gravitons. It is established but it's not scientifically proven. If it was, then it would be a scientific theory, but it's not, it's a model.https://en.wikipedia.org/wiki/Gravitational_field

I don't watch movies since my concentration is messed up. I don't play with myself since it doesn't give me a nice feeling and costs me a lot of energy. I have a neuromuscular disease. Thanks for reminding me.

[beecee]

15 minutes ago, Itoero said:

No I don't mean gravitons. It is established but it's not scientifically proven. If it was, then it would be a scientific theory, but it's not, it's a model.https://en.wikipedia.org/wiki/Gravitational_field

I don't watch movies since my concentration is messed up. I don't play with myself since it doesn't give me a nice feeling and costs me a lot of energy. I have a neuromuscular disease. Thanks for reminding me.

 

17 minutes ago, Itoero said:

No I don't mean gravitons. It is established but it's not scientifically proven. If it was, then it would be a scientific theory, but it's not, it's a model.https://en.wikipedia.org/wiki/Gravitational_field

I don't watch movies since my concentration is messed up. I don't play with myself since it doesn't give me a nice feeling and costs me a lot of energy. I have a neuromuscular disease. Thanks for reminding me.

It gets quite boring reminding those that profess to know about science, that scientific theories do not align with "proof"

From your link....In a field model, rather than two particles attracting each other, the particles distort spacetime via their mass, and this distortion is what is perceived and measured as a "force". In such a model one states that matter moves in certain ways in response to the curvature of spacetime,

This curvature of spacetime/gravity is evident  by many means and aligns with it being a field

[Itoero]

3 hours ago, Strange said:

It may show that. But theories based on that idea haven't worked so far. So the overwhelming evidence is that it is matter.

Which theories? I just posted a link to a new theory in 'Astronomy and Cosmology'.

 

[swansont]

3 hours ago, Itoero said:

Not Gravity, the existence of a gravitational field is not scientifically proven. The evidence for gravitational field is based on mathematical logic.

The gravitational field, like many things in physics, is a calculational tool. The question of whether it physically exists is metaphysics.

Quote

We don't know enough about gravity to assume there is a gravitational field.  The fact that we can't explain star-dynamics (dark matter) shows our understanding of gravity lacks to know there is a gravitational field.

Gravity, as a phenomenon, exists. We are quite confident that it follows Newtonian gravity in most of our solar system (and GR in most cases where Newtonian gravity fails) Therefore, there is a gravitational field of the form a = GM/r^2 

That's your field. It's really not any more complicated than that. 

Quote

A while back someone created a new Gravity theory.

"In 2010, Erik Verlinde surprised the world with a completely new theory of gravity. According to Verlinde, gravity is not a fundamental force of nature, but an emergent phenomenon. In the same way that temperature arises from the movement of microscopic particles, gravity emerges from the changes of fundamental bits of information, stored in the very structure of spacetime."https://phys.org/news/2016-11-theory-gravity-dark.html

This would not even be newsworthy if it completely disagreed with GR (which means it can't disagree with Newton). So it says nothing about gravitational fields not  being "proven"  They would simply have another form with this model.

 

[Strange]

1 hour ago, Itoero said:

Stop misinterpreting me. I don't prefer a mathematical model. I only stated there is an other theory about Gravity. It's not a mathematical model and it does not debunk current evidence.

If it were not a mathematical model (it is) then it wouldn’t be a scientific theory. 

But there is no evidence for it. 

[Itoero]

2 minutes ago, beecee said:

22 minutes ago, Itoero said:

 

It gets quite boring reminding those that profess to know about science, that scientific theories do not align with "proof"

It depends what you consider to be 'proof'. Our Gravity theory can't explain stardynamics. We our made of 'Stardust'.  So our Gravity theory lacks to explain our natural world. 

[swansont]

1 hour ago, Itoero said:

Stop misinterpreting me. I don't prefer a mathematical model. I only stated there is an other theory about Gravity. It's not a mathematical model and it does not debunk current evidence.

It most certainly is a mathematical model. Didn't you look at his paper and see all the equations?

[beecee]

19 minutes ago, Itoero said:

It depends what you consider to be 'proof'. Our Gravity theory can't explain stardynamics. We our made of 'Stardust'.  So our Gravity theory lacks to explain our natural world. 

No it does not depend on what you consider to be proof. A scientific theory is always open for modification, change or totally scrapping as further evidence comes to light. Although as scientific theories continue to withstand scrutiny, they do become more and more certain.   And of course gravity can show star dynamics...in fact gravity explains how the universe is what we see today, stars, planets, galaxies, stellar remnants  etc. Perhaps you need a rundown? 

[Strange]

5 hours ago, Itoero said:

Not Gravity, the existence of a gravitational field is not scientifically proven.

Strictly speaking, nothing is scientifically proven. 

5 hours ago, Itoero said:

The evidence for gravitational field is based on mathematical logic.

The evidence is based on observation and measurement. 

The theory/model is based on mathematics. 

The evidence is consistent with the theory. 

That us true of gravity, magnetism, quantum theory, atoms, chemistry, physics, cosmology, ... basically all Of science. 

It will also be true of Verlinde’s theory if there is ever any evidence for it  

That is how science works. Not by “proving” things. And certainly not by proving things are real or exist. 

1 hour ago, Itoero said:

Which theories? I just posted a link to a new theory in 'Astronomy and Cosmology'.

And there is zero evidence that that theory can explain dark matter. 

There have been many attempts to explain dark matter in terms of modified gravity (among other things). So far, none of them match all the evidence (unlike dark matter as matter). 

[Itoero]

On ‎22‎/‎08‎/‎2018 at 11:47 PM, Strange said:

Strictly speaking, nothing is scientifically proven. 

Not really. Nothing is 100%proven but things are very often scientifically proven, like that lights is made of photons, for example. Quantum-gravity theories, the holographic principle, quantum interpretations need to be scientifically proven to become scientific.

On ‎22‎/‎08‎/‎2018 at 11:47 PM, Strange said:

The evidence is based on observation and measurement. 

The theory/model is based on mathematics. 

The evidence is consistent with the theory

How can the evidence be consistent with the theory if we have to implement dark matter? The theory lacks. There is probably a gravitational field. But it's impossible to really know it.

And why are people so certain the field model is correct? That means the point attraction is wrong.

On ‎22‎/‎08‎/‎2018 at 11:47 PM, Strange said:

That is how science works. Not by “proving” things. And certainly not by proving things are real or exist. 

In 'science' things are proven all the time, like wave particle duality. I suppose general relativity is proven many times.

 

On ‎22‎/‎08‎/‎2018 at 11:47 PM, Strange said:

And there is zero evidence that that theory can explain dark matter. 

There have been many attempts to explain dark matter in terms of modified gravity (among other things). So far, none of them match all the evidence (unlike dark matter as matter). 

'The new theory  makes the same predictions without dark matter'...isn't this correct? I didn't read the paper.

Edited August 24, 2018 by Itoero

[Phi for All]

26 minutes ago, Itoero said:

Not really. Nothing is 100%proven

Being "proven" is like being pregnant. It's not a variable state. Once again, you're taking a word that has very specific meaning, and you're loosening its definition to suit your ideas, and in the process you make the word meaningless for the rest of us.

"Proven" is automatically 100%, and science doesn't work that way. In case you missed it the other thousand times you've been told this in discussion here.

[Strange]

39 minutes ago, Itoero said:

Nothing is 100%proven but things are very often scientifically proven, like that lights is made of photons, for example.

There is just about the same level of evidence for photons as there is for GR. 

39 minutes ago, Itoero said:

Quantum-gravity theories, the holographic principle, quantum interpretations need to be scientifically proven to become scientific.

No. They need to be testable to be scientific. (Although the definition of “scientific” is broader than that.)

39 minutes ago, Itoero said:

How can the evidence be consistent with the theory if we have to implement dark matter?

Because if we add matter (in the distribution it would naturally have, given its properties) then observations match the theory. 

If you had been around when the gravitational effect of Neptune had been seen (but Neptune had not) would you jump to the conclusion that our theory of gravity is wrong? Or, maybe, more realistically that there is a planet we haven’t seen yet. 

Obvioudly we need to consider all possibilities, but to assume the obvious and simplest answer must be the wrong one is just perverse. 

39 minutes ago, Itoero said:

In 'science' things are proven all the time, like wave particle duality.

That is no more “proved” than the existence of photons or electrons. It is part of a good model. That doesn’t make it “true”.

39 minutes ago, Itoero said:

The new theory  makes the same predictions without dark matter'...isn't this correct? I didn't read the paper.

The authors of the theory claim that. They also claim some evidence supports it. Others say there is evidence that contradicts it. 

So I wouldn’t assume too much yet. 

[swansont]

3 hours ago, Itoero said:

How can the evidence be consistent with the theory if we have to implement dark matter? The theory lacks. There is probably a gravitational field. But it's impossible to really know it.

So what? GR says nothing about the specifics of mass. It's not part of the theory.