Gravity and the Expanding Universe

[lucaspa]

As you say, it is space itself that is expanding. But what is it expanding within?

 

Nothing. You have stated a limitation of our minds that we have to work around. We are used to seeing only expansion of something into an existing space. But the expansion of space is something else. There is no space to expand into. So we have to accept the data and try to get our minds to wrap around that concept.

 

On your other point, I am linking gravity to mass but I am not suggesting classical views of this effect are wrong. I'm suggesting that the search for a field, graviton etc. might be wrong.

 

That is apples and oranges. You have two separate things and you tended to confuse them, and thus confuse us as to what you were saying. As far as I can tell, you are saying:

1. Gravity is a property of mass.

2. There are no gravitons or gravitational "field".

 

As I recall, Einstein said that gravity was a warping of space with the amount of warping being proportional to the mass. However, since effects for other phenonmenon -- such as electromagnetism -- are mediated by "particles" between objects, it is permissible for physicists to posit such "particles" as gravitons and go look for them.

 

Since the exact same effect can be experienced in what appears to be two completely different ways then perhaps only one of the events is the real cause of gravity.

 

Uh, you went beyond what the data says. Einstein says that acceleration and gravity are equivalent in their effects. Einstein never said anything about causes. It's obvious that acceleration is due to one cause and gravity to another.

 

Perhaps we just don't know we are accelerating. As far as I know there isn't any direct evidence of a 'gravity particle' and so why restrict the search to just that?

 

As far as I know, the search is NOT restricted. It's one avenue of approach. A very popular one, to be sure, but not the only one. Loop quantum gravity, for instance, does not look for a gravitron.

 

3. An effect of acceleration through another medium.

 

This one can't be right. As I pointed out with the gravity of earth and Jupiter, according to this possibility, the gravity should be the same since they are both accelerating in the universe together. But gravity isn't the same. So this possibility must be wrong. Sorry.

[JohnF]

I do think that the warping of space/time, for want of a better description, is the primary force we feel and call gravity. The 'acceleration' I refer to, through this other medium, produces a cumulative effect. The more particles accelerating, the more the distortion of space/time. This is why Earth and Jupiter have different gravitational forces.

 

So there are two main questions. What causes the distortion in space/time? Is it just mass, like the displacement caused by a ship, or is it acceleration or movement through space/time, like the displacement you would get in water when a submarine moves through it.

 

The other question is based on the assumption that a distortion of space/time causes what we feel as gravity. Are we being pulled towards a centre of gravity or are we being pushed towards one? Could it be the 'pressure' of space/time that provides the force?

 

Slightly off topic but I wonder, can you have anti-mass and would it have a negative gravitational force?

[Norman Albers]

Now, as far as I know, the gravitational attraction rate has been [math]9.81\frac{m}{s^2}[/math] since it was first determined!

 

Gravity is just an occurring phenomenon between particles with mass, just like the attraction or repulsion that occurs between charged spheres!

 

Dude, gravitation rate of what? (Earth mass) "Just...", well, sort of. Actually I say it is the neutral mode of the common vacuum field.

[elas]

[b}Since the universe occupied such a small space at the start then it would seem that the space between each particle has increased.[/b]

 

Where is the proof that there is space between particles?

[thedarkshade]

What do you mean elas? What do you actually mean when you say space? Please define it!

[elas]

thedarkshade

 

What do you mean elas? What do you actually mean when you say space? Please define it!

 

At present the majority view is that particles are ‘point-like objects with ‘space between them (sometimes filled with ‘quasi particles’!). There is however a growing minority view that there is no gap between particles try entering Stochastic Electrodynamics on Google.

Malcolm H Mac Gregor has written two books related to the arguments involved, I am waiting for a copy of the second. My own contribution is on the Speculations forum and I would be breaking the rules to repeat it on this forum. But, if you repeat the question in ‘Speculations’ I can reply in detail.

[thedarkshade]

PM me so I can get a better picture of what you're talking about.

 

If you're referring to the space (for example) between electrons and nucleus, it's not really space, it's filled with electron wave.

 

Sorry if I don't reply fast, but this is gonna be a hell of a busy week for me. I've got some tricky trig math tests and I really need to practice them a lot.

 

Thanks for your time!

[Zelos]

Everyone knows the gravity fairies are what causes gravity.

But it's an interesting concept. Not the gravity fairies, what you were talking about.

[JohnF]

I suppose that if acceleration does distort space/time and this distortion causes gravity then a space vehicle accelerating at 1G might create a disturbance in space/time that could be detected by a non-accelerating device in the wake of the space vehicle.

[thedarkshade]

I suppose that if acceleration does distort space/time and this distortion causes gravity then a space vehicle accelerating at 1G might create a disturbance in space/time that could be detected by a non-accelerating device in the wake of the space vehicle.

John, gravity is nothing but stretch and wraps of space-time fabric!

You like it this way?

[Klaynos]

thedarkshade

 

What do you mean elas? What do you actually mean when you say space? Please define it!

 

At present the majority view is that particles are ‘point-like objects with ‘space between them (sometimes filled with ‘quasi particles’!). There is however a growing minority view that there is no gap between particles try entering

 

Please tell me you're kidding?

 

And we can show that tehre's space between particles just fly veyr high in an unpressurised plane....

[Norman Albers]

John, gravity is nothing but stretch and wraps of space-time fabric!

The fabric is the vacuum which is characterized by zero-point energy fluctuations. The point of Polarizable Vacuum theory is that gravitation is the result of the thickening or strengthening of what we call vacuum permittivity or [math] \epsilon_0[/math].

[Klaynos]

The fabric is the vacuum which is characterized by zero-point energy fluctuations. The point of Polarizable Vacuum theory is that gravitation is the result of the thickening or strengthening of what we call vacuum permittivity or [math] \epsilon_0[/math].

 

I'm baffled, completely baffled... what do you mean? Does this make any sense to anyone, please help me!

[thedarkshade]

I'm on your side Klay!

 

Puzzled:(

[Norman Albers]

What are you saying when you say, 'the vacuum has an electric pemittivity of such and such, or a magnetic permeability of so and so'?

[Klaynos]

A fundemental physical property of the universe such that:

 

[math] c^2 = \frac {1} { \mu_0 \epsilon_0}[/math]

 

A limiting factor on the propagation of EM waves.

[Norman Albers]

I say it is, rather, a local property of space, and that relativity is built on the idea that physics is the same, locally, everywhere.

[Klaynos]

I say it is, rather, a local property of space, and that relativity is built on the idea that physics is the same, locally, everywhere.

 

OK... I can understand that.

 

I'm assuming you know that c being constant everywhere is a result of electrodynamics?

[Norman Albers]

I am doing mathematical work as I express in my 'Reissner-Nordstrom' thread and several others. If you have not spent time with my paper on gravitation, you should. I feel frustrated because I have spent so much effort trying to communicate what I have to offer, and I feel I should not take more time and space on this forum.