[jeffreyH (OP)]

One thing that never gets mentioned with respect to gravitational issues is parallax.

That's because there's no reason why it should. It has absolutely nothing to do with gravity. It only pertains to optical observation of celestial bodies. Why do you think it should have anything to do with gravity at all?

We take it for granted but there are issues to do with this effect on a local scale.

When making assertions like this its helpful to back it up with facts. E.g. what are these issues that you're referring to?

If you had a disc whose circumference was 300000000 meters you could never achieve one revolution per second as the angular momentum would reach light speed at the edges. Length contraction would be greater at the edges of the disc as it approached light speed which would mean that the spacetime distortion would produce strange parallax effects. Gravitation and momentum cannot be separated so these effects are important in understanding these forces.

[Pmb]

If you had a disc whose circumference was 300000000 meters you could never achieve one revolution per second as the angular momentum would reach light speed at the edges. Length contraction would be greater at the edges of the disc as it approached light speed which would mean that the spacetime distortion would produce strange parallax effects.

First let's be clear on something. The contraction of the circumference of a disk does not mean that there is any spacetime distortion whatsoever. The only way that spacetime can be distorted here is due to the energy of the rotating disk rotating such that parts of it have near superluminal speeds.

All you're really saying is that light is bent by gravity. Bringing in parallax only serves to confuse things. There's no need for it to be quite honest.

Let's be clear here. Parallax is defined as follows
http://en.wikipedia.org/wiki/Parallax

Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.

Bringing in parallax confuses things and as such I recommend not using it in this sense.

Gravitation and momentum cannot be separated so these effects are important in understanding these forces.

Why are you now bringing momentum into this? And why would you make such a statement as this? What does it have to do with the present subject? And momentum is not a force either.

Some of the stuff you say is really confusing Jeff.

[jeffreyH (OP)]

Think of the parallax effects of frame dragging. This is a similar situation. This is the reason c^2 is related to mass-energy and not any other value. The effects at light speed and under gravitation have intimate links.

[Pmb]

Think of the parallax effects of frame dragging.

Since parallax has nothing to do with frame dragging I have no idea what you're talking about. Sorry.

This is a similar situation. This is the reason c^2 is related to mass-energy and not any other value.

The reason c² relates mass to energy is due to its presence in the Lorentz trasformation. How you connect it otherwise is beyond. How did you come to such a conclusion?

The effects at light speed and under gravitation have intimate links.

"Under" gravitation? Is that an error? In any case you once more lost me.

[jeffreyH (OP)]

Think of the parallax effects of frame dragging.

Since parallax has nothing to do with frame dragging I have no idea what you're talking about. Sorry.

This is a similar situation. This is the reason c^2 is related to mass-energy and not any other value.

The reason c² relates mass to energy is due to its presence in the Lorentz trasformation. How you connect it otherwise is beyond. How did you come to such a conclusion?

The effects at light speed and under gravitation have intimate links.

"Under" gravitation? Is that an error? In any case you once more lost me.

Under the influence of gravitation.

Think of mass for a moment. What property of mass produces gravitation? If we take a number of spheres 1 meter in diameter made of iron. If these spheres were contained within a mesh to produce a spherical shape we could produce something that looks like a planet. If the mass of the spheres plus the mesh was the same of the mass of the earth then what would the combined gravity be when placed in the same orbit as the earth? Each sphere has its own gravitation which drops in an inverse square relationship and individually are much weaker than that of the earth. A very pertinent point is whether the gravitation would accumulate under these conditions. Would we reproduce the field strength of the earth? Before I can elaborate on other ideas this point needs to a answered conclusively.

[Pmb]

Think of mass for a moment. What property of mass produces gravitation?

Mass doesn't have any properties. Mass is a property. Therefore your question is meaningless.

[jeffreyH (OP)]

Think of mass for a moment. What property of mass produces gravitation?

Mass doesn't have any properties. Mass is a property. Therefore your question is meaningless.

The properties of mass are surely gas, liquid, solid, plasma etc. Or if you prefer, states.

[Pmb]

The properties of mass are surely gas, liquid, solid, plasma etc. Or if you prefer, states.

Sorry but that's not going to work either my friend. Those are the properties of things that have mass, not the properties of mass.

[jeffreyH (OP)]

The properties of mass are surely gas, liquid, solid, plasma etc. Or if you prefer, states.

Sorry but that's not going to work either my friend. Those are the properties of things that have mass, not the properties of mass.

Yes mass is a property of matter but properties can themselves have properties. Colour, for instance, has the properties of luminescence and brightness. I specifically did not relate the properties to matter as I believe it is the mass that is the defining factor with relation to gravitation. An atom will have less gravitation than a molecule, which in turn has less gravitation than a solid made up from molecules.

[Pmb]

Jeff - This is getting way off subject and I'm not interested in this side track. What exactly is it you wish to discuss or ask me about? Thanks! - Pete

[jeffreyH (OP)]

Jeff - This is getting way off subject and I'm not interested in this side track. What exactly is it you wish to discuss or ask me about? Thanks! - Pete

Well I suppose what I want to discuss is this.

http://burro.cwru.edu/Academics/Astr221/LifeCycle/jeans.html

The Jeans criteria for gas collapse under gravitation. What does this process tell us about gravity?

[Pmb]

Jeff - This is getting way off subject and I'm not interested in this side track. What exactly is it you wish to discuss or ask me about? Thanks! - Pete

Well I suppose what I want to discuss is this.

http://burro.cwru.edu/Academics/Astr221/LifeCycle/jeans.html

The Jeans criteria for gas collapse under gravitation. What does this process tell us about gravity?

I don't know. That's astrophysics and in astrophysics I'm a layman, just like you.

[JP]

The Jeans criterion seems to be fairly straightforward from that link.  Basically,  a bunch of particles of gas in space will tend to attract each other and coalesce to form a star.  However, in actuality, gas particles move about due to the temperature of a gas and this motion can keep them from clumping together (if they get too close, they'll bump into each other and fly apart again).  Basically, if there's enough mass in a cloud of gas compared to the temperature of that gas, it will coalesce into a star.  If the temperature is too high compared to the mass, it will stay a cloud of gas and not form into a star.

[jeffreyH (OP)]

The Jeans criterion seems to be fairly straightforward from that link.  Basically,  a bunch of particles of gas in space will tend to attract each other and coalesce to form a star.  However, in actuality, gas particles move about due to the temperature of a gas and this motion can keep them from clumping together (if they get too close, they'll bump into each other and fly apart again).  Basically, if there's enough mass in a cloud of gas compared to the temperature of that gas, it will coalesce into a star.  If the temperature is too high compared to the mass, it will stay a cloud of gas and not form into a star.

Interesting. So then a fall in kinetic energy should initiate gravitational collapse for a mass of sufficient density. This appears to show that gravitation tends to aid in the solidification of matter somehow. Does this also suggest that spin 2 particles operate to initially reduce kinetic energy for matter moving away from the source of gravitation? What better way to add matter to a mass than hurling it inwards.

[jeffreyH (OP)]

This train of thought got me thinking about singularities with regard to the mass-energy density topic. If increase in gravitation reduces kinetic energy and the reduction in kinetic energy leads to time dilation (rate of atomic change slows down) then the singularity is an inevitable consequence of gravity and the ideal equalibrium for such a force. A question of interest would be this. What would an observer outside the earth determine would be the speed of an object falling to earth under gravitation? How many metres per second of acceleration would they record as compared to an earth bound observer?

P.S. Does this imply zero kinetic energy at the singularity? Could frame dragging occur because it is moving around a time-free zone and is forced to do so because of the consequences of the lack of kinetic energy at the singularity?