Gravity and The Curvature of Space Question

[mjc]

Here's something I can't get my mind around.

Take a black hole. There is no path from any point within the event horizon to any point outside of the event horizon - no outward path. Space is curved back onto itself and any path for a photon that is within the event horizon leads to the singularity.

So - if I've got this correctly. Get a wire frame to represent the three spatial axes and place it within the event horizon. Now as we we migrate along any of the axes we find ourselves at the singularity.

But we have have an inward direction that allows for material to cross over the event horizon from the outside to the inside. This could possibly (or possibly not) be rephrased as there is a direction - independent from the three spatial dimensions - that allows a vector to be constructed that gravitationally binds an object outside of the event horizon and the singularity - and possibly any object that has crossed the event horizon but has not yet reached the singularity.

So in how many "directions" is gravity operating - the three internal (within the event horizon) spatial 3D plus radially outwards (what ever that means) in an external 3D frame of reference - is that effectively six - and how would that effect any test of the inverse square law?

Its a brain teaser for me.

I'm not trying to be provocative - its a genuine Winnie the Pooh type of experience - you know - "I'm a bear of little brain and big words bother me".

If I got a nudge or a clue I'd be happy.

Mark C.

[CraigS]

G'Day Mark !

Welcome back !!

I'm not a very good answerer of these kinds of questions (other folk are more qualified) but it seems to me that the force due to gravity around a black hole (or any other matter dense body) is directed inwards, towards the centre.

If the hole is rotating, then I would think that the net resultant direction, due to gravity would be along curved lines, as this kind of BH drags spacetime with it, (outside of the event horizon).

I don't see the need for extra dimensions in all of this.

Also, the Event Horizon is unnoticeable to a falling body. It is only noticed by an observer. I think a photon is theorised to move in curved world lines inside the Event Horizon … (but this can still be envisaged within the normal three dimensions).

Over to others.
Good to have you back.

Cheers

[Robh]

Mark,

Does anyone really know what happens inside the event horizon?
I can't comment about the internal physics but this is my opinion of the picture outside it.
Consider objects with different mass traveling at the same velocity towards a common centre in a plane, each object initially at equal distance from this centre. Now move the plane near a black hole (non-rotating) so that a radial line from the centre of the black hole is normal to this circle at its centre. The path of the objects will lie on a surface which was the plane but is now symmetrically distorted towards the black hole relative to the normal. This is the picture of a sink hole given for the black hole or equivalently a representation of the curvature of space around the black hole. To a distant observer the path of each object is essentially similar and two dimensional and distances covered will diminish with time as the objects approach the event horizon. At the event horizon, the objects appear to stop.
The visual representation of a sink hole around a black hole is not entirely accurate and is for impression only. There are an infinite number of such planes that will form their own sink holes relative to the black hole. A picture of this cannot be drawn in three dimensions.
However, for a single object, the path is essentially two dimensional with a relativistic time component.

Regards, Rob.

[mswhin63]

Black holes are contraversial for a lot of people and a very difficult thing to actaually prove due to sperical bulb of light surrounding the location suspected on being the black hole.
Determining if an location in space is a Black Hole is determined by XRay ejection. Is it possible the Potons or something are all sucked in are converted the XRay emmisions and able to escape. Who know what kinds of physics occur at such great speed. I believe Neutrino espcape as these travel faster than light.

Black Holes are essentially rotating Star of emmence proportions both small mass and large gravity, but they don't spin in a 3D rotation so it should look like a double ended whirlpool. I would also FEEL the sucking energy on both axis would be the same as the repelling energy around the equator of the spinning mass in the centre. So what happens on the edge I am not sure at the moment still learning.

I am long way off learning about black holes and whether they are real or not or even how they operate. What is real is that a high mass object is spinning at a great velocity and it is capable of sucking in mass. Photons are I think are pure energy so how is mass able to spin as fast than pure energy I do not know and find this hard to get my head around.

Disclaimer: I am not qualified to make a comment so dont beat me up please. I also have feelings. I am considering seriously about going back to school. Maybe I am too old.

[CraigS]

:)
Hey Malcolm … that's cool .. we all have 'em (feelings) .. I've been beaten up heaps around here, too
;) :)

Come to think of it, I got beaten up at school, also !
I don't think you can escape at school, regardless of age !!
:):lol::)
(Just kidding around).

Cheers

[CraigS]

Whilst its a bit sneaky of me, Steven once said (in another thread (http://www.iceinspace.com.au/forum/showthread.php?p=631331&highlight=geodesic#post631331) which got onto black holes and gravitons):



Don't you hate it when someone digs up stuff from the past ?
:)

I never did quite get to the bottom of this one, though (which is kind of why I dug this up).
I presume this is fairly speculative and I hope he doesn't mind.

Cheers

[xelasnave]

I find it difficult to understand how whatever boson one may select to convey the message of gravity can get off or move away from the extremely curved grid of space time.... How can our graviton move away from the constricted path dictated by the extreme space time curvature such that it can tell the space outside the event horizon that within there be a black hole...it would seem that whatever particle one selects to construct a gravity field it will be incapable of escape and bound to follow the extreme curvature suggested to exist at and past the vent horizon.
alex

[mjc]

Rob - very well expressed.

Alex actually captured my conundrum - though I wouldn't use the language expressed. However - I'd like to leverage of Alex's reply - as it was more succinct. Basic problem is how can space-time be curved in on itself and information still be exchanged between the singularity and a mass outside of the event horizon.

That implies that there is a path from within the event horizon to out side - as outside knows what mass lies within the event horizon.

My line of enquiry doesn't seek to challenge existing theory - merely to inch towards a better understanding of what current theory says. But I have a suspicion that General Theory of Relativity is such that one probably needs to have a mathematical appreciation as qualitative explanations are just going to be an oversimplification to the point of being useless.

I appreciate Alex's comment - as it is so succinct.

Rob, your comment regarding knowing what happens at the other side of the event horizon is also thought provoking. From what I read - nothing changes other than all paths lead to the singularity and hence no particle can move from the inside to the out side. If the black hole were sufficiently massive then the gravitational gradient may not be that great across a short distance that crosses the event horizon and an observer crossing the event horizon wouldn't really experience any change to his environment when he crossed it - physics is still predictable. But an observer outside would not see this - but can predict it. Again, from the perspective of an outside observer timings of events as they approached the event horizon would slow down. But what we see is increasingly red-shifted to the point where we can't see them any more. Now - at some point (post event horizon) closer to the singularity our laws of physics may break down for the observer that is falling in - and at the singularity - I would expect this as I'm sure there are many equations that have the radius - or distance from centre - as a denominator and when you get zero we have stuff that can't be computed. I'm of the understanding that it is the division by zero is what mathematicians call a singularity.

I can buy a lot of this but its the conundrum of how information is shared (re gravity) between inside and outside of the event horizon that I can't visualise.

Mark C.

[xelasnave]

Hi Mark your comment....

But I have a suspicion that General Theory of Relativity is such that one probably needs to have a mathematical appreciation as qualitative explanations are just going to be an oversimplification to the point of being useless.

is absolutely correct:thumbsup:. Usless in the context that the math becomes the delight of discovery rather than grappling with the major problems our original premise has left us with...blach hole equales nothing can escape...even gravitons??? we can not happily rush past such an anomoly:D.

The point is GR is in effect an attempt to provide humans with some understanding of something perhaps that will forever remain beyond our comprehension.

Notwithstanding the complexity of the maths (try getting your head around the 11 field equations) GR is geometry where we use x y and z axis and then incorporate a negative "time" line..to descibe to measure to quantify ...space...whatever space is:shrug:.. understanding the math and focusing upon its value without additional regard to the difficulties we are left with if we rely upon the extrapolations GR suggests.

I find it interesting that Dr Einstein found great difficulty in excepting the black hole idea and given he is the man who gave us general relativity I for one take such as reasonable support to question the likelyhood of their very existence.

However irrespective of how complex one may wish to call the math of GR if one follows it we come to difficulties when considering "extremes" ..in my view.

One such extreme is the difficulty of working out a path for messenger particles (the standard model of particle physics suggest and endorses such concept..bosons I think:shrug:...certainly outside the event horizon we can easily speculate to a point where we can move stuff about but once inside we must content with the logic and conscequence of the null geodesics which tells us clearly... whatever be on this path will remain on that path forever or until the laws of GR collapse or are modified to overcome what would seem a mecahism which prevents all and any activity at any level ....

The complexity one wishes to place upon the math or perhaps more correctly the geometry we work in GR should not be enlisted to dump such relevant questions you raise.. In seeking an answer something perhaps will need adjustment be it the math or indeed the very premise of a balck hole.

AND I know when one questions the existence of black holes all will laugh at the apparent ignorance of the proposer to all the "black hole discoveries" now cataloged. THey are fact not speculation we are told ..and yet I say this..until the problem of how messages pass between a balck hole and the rest of the universe is satifactorily addressed we have a grave problem which can not be dismissed merely by reference to a lack of understanding of the math... the math is there to make ideas managable by a human mind not to exclude logical thought on perplexing matters one could suggest.

Prof Hawking spent much time considering the memory problem for matter within a black hole... or once matter has been crushed or smashed or experienced whatever condition we can speculate may occur within a balck hole the question is raised ..what if this matter gets free can it remember what it "was" and "go back" so we can enjoy managing all sorts of problems within our black hole .... however it would be wise to remember we possibly speculate upon conditions within a body that may be very different to what we mathmatically have determined in the absence of specific observation.

alex:):):)

[CraigS]

Mark;

From what I’ve read, the perspective of what the observer outside the Event Horizon sees, is directly related to which model one chooses to employ, to envisage what might happen. Quantum Field theory for instance, says that objects appear to break down into progressively smaller objects – ever smaller. But as the parts of it become as small as Planck length, a new pattern somewhat akin to Russian Dolls appears. Things inside things. They move, and the smaller they are, the faster they move. More and more structure appears.

String theory however shows that they occupy an increasing amount of space, so that the entire structure falling into the EH, grows. The strings vibrate in a special, predetermined way and eventually become so big, they spread over the entire horizon of the Black Hole.

The story continues to be different as we move into strings attached to D-Branes, for example, (which obey the same rules as Quantum Chromodynamics).

So, if there are differences between what each theory says about what an observer sees, the information conveyed to that observer, is clearly different. The means of that conveyance is related to the definitions of each theory's respective, fundamental constituents.

This problem is at the cutting edge of theoretical development and physicists all over the world have not yet resolved it. You are not alone in your conundrum. I suggest you take a more detailed look at what each theory says happens, as a next step. There are no easy answers to this, and most answers from this point onwards are directly related to the knowledge of the answerer. They are partly theoretical, and increasingly speculative, as one goes further into them.

Cheers & Rgds.

[Robh]

Alex,

You are assuming there has to be a messenger particle like a theorised graviton. But what if mass simply bends space so that objects follow geodesics on this space curvature in travelling from A to B? Consider a river whose path is guided by the contours of the landscape. The river is the flow (geodesic) and the landscape is the analogy to the mass which shapes the geodesic. A boat simply follows the course of the river. It does not need to communicate with the landscape itself. Even an electromagnetic field, which directs the path of an electron, can be considered a river with essentially no necessity for a messenger particle. General relativity basically treats gravity as a field theory and so far has worked pretty well.

Regards, Rob

[xelasnave]

Hi Robh
Yes indeed my view is formed no doubt from my desire to have a "mechanical" explanation and so particles speculated upon such as a graviton are of interest.... however it was not I that came up with the graviton or the boson and the fact that others greater than I have arrived at such hypothesis does not make my thoughts out of bounds.

The premise of general relativity is very much as you suggest things may be..it just is.... if asked for a simple explanation of general relativity one could answer that it is a concept that attributes space with certain properties "that just are" particularly that space is "bent" by mass.

The geometry lets us then look at gravity as little more than the shortest path between two objects with mass and this "shortest" distance is in effect the result of the bending of space.

However at the risk of over simplification what we deal with is a geometric construct with no reference to how space does what we attribute to its working.

I simply contend that there must be more at work than geometry. We use geometry to plan a house and such plan is invaluable during construction...but the plan is not the house..the house finally will be constructed with real things each capable of classification and measurement.

In the case of the flow of a river it is clear rivers flow to the sea... that is simlar to saying mass bends space and time but further consideration enables us to propose that it is the difference in height at either end of the river and what we observe is water flowing to the lowest point..again similar to the space time bend approach..but there is something happening at a particle level one could expect that enables particles in the river to chose which way they must travel...


In any event if we stick doggedly to the notion that space bends and that is the end of it we simply dabble with geometry and avoid adding any reason as to why the geometry dictates what we observe.. we can draw the house plans but then offer no candidates for the materials to be used in its construction....as I understand it physisits are happy to stop at the geometry point and that is fair but I think we will miss a grander story..and the grander story does not have to conflict with GR in fact one reasoning should and must compliment the other.

I think to offer nothing more than geometry misses the point and folk are so happily indulging the math they fail to recognise that probably things dont happen as if by magic but there is possibly a particle conection and interaction...

Also I ask..how can folk happily indulge speculation upon what happens in a black hole if nothing can escape...even presumably any possibilty of an observation that will support any of the speculations presented.

I think my consideration that a feild must be made up of some particle flow is far from unreasonable in terms of speculation when one considers the speculation other indulge when it comes to black holes.

Frankly I think its like arguing about what Hobbits have for their second breakfasts;)
Have to go will edit this later it was a rush..
alex :):):)

[CraigS]

Ahh Alex;

Good to see you back.
:)
I have been thinking about you and our many discussions.



But someone has invented a graviton. Quantum Field theory and Quantum Chromodynamic theories have been created as has String and M-theories. Someone has spent billions of dollars building particle accelerators and observatories looking for gravity waves. Doesn't this show that someone is pursuing the grander story ?



Bu this is someone else's theory .. are you claiming it as your own ??….



???

Cheers & welcome back ! :)

[xelasnave]

Good to see you back.
:)
I have been thinking about you and our many discussions.

Thank you Craig.


But someone has invented a graviton. Quantum Field theory and Quantum Chromodynamic theories have been created as has String and M-theories. Someone has spent billions of dollars building particle accelerators and observatories looking for gravity waves. Doesn't this show that someone is pursuing the grander story ?

Yes it does... I feel better ..there was a time where I felt I was the only one who cared;)

Bu this is someone else's theory .. are you claiming it as your own ??….

Not for a moment. My point is simply this..the aspect of messenger particles is within the current cold dark matter theory of particle physics and given this it would seem relevant to fit that in ... where who knows but you have my view at least...It is my suggestion that fields rely upon a flow of particles and gravity fields may work this way.
Perhaps my extreme humility on all matters make it difficult to understand my points:D
Craig if there is one thing my many orbits around our star has show to me is this..the are very few original ideas... folk around here think I think outside the box but in truth most things I mention have been published before.

For years I developed the push universe only to find that as early as 1745 Le Sage had been working along similar lines... but this was wonderful because it released me from the duty of working it all out in detail.. to that point I saw my duty to humanity as showing folk how gravity may work..mmm also my TOE I felt could help... and now there seems to be many folk working along the lines that fit my approach...not from my influence but simply developing their ideas on the workings of everything. AND so I say that I claim nothing from this world by way of recognition or wealth because I have come up with anything useful.

Mind you I am working on a sailing vessel to take the world record and so far the design seems original.... but once I invented a boat paddle which I built and used only to find the same on an old Chinese wood print. In fact all of my inventions seem to have been done before.... no I claim nothing other than the right to be here and live out my final years in peace.



???
I merely used the little I read on same to try and fit it in someplace.
Cheers & welcome back ! :)

Thank you Craig. I do read here a lot but given my travels can not post and compliment you upon the many interesting threads you start. I do feel that many folk get some love of physics through the interesting subjects you raise.

alex:):):)

[CraigS]

Thanks for your compliments, Alex, (although many might argue about my choice of topics). ;)

[Robh]

Alex,

I think your attributing too much importance to the existence of a particle in considering gravitational forces. The effects of these forces can quite happily be described without knowing the properties of any supposed carrier particle.

Consider the boat in the river. Studying the composition of a water molecule alone will tell you nothing about the river's speed and course. The speed and course of a river varies primarily according to external factors (e.g. incline and contour of the valley).
Consider another analogy. A tornado whisks a car up and throws it some 100 m away. Is the idea of a messenger particle relevant to this action? Not really. Sure, the air is composed of molecules but these molecules exist even when the tornado doesn't. The molecules constitute the air flow but the air flow is a result of extraneous factors (e.g. heat of the Sun on land and water). Studying the composition of an air molecule (and there are many different types of molecule) won't tell you why the car landed over their. Studying the holistic behaviour of a mass of air molecules and the forces it produces is relevant. This behaviour largely depends on differences in air temperature and pressure around regions and patterns are studied over time to make predictions.

If there is a graviton then how important will it be to a description of the forces due to gravity? Like a single air molecule, a description about the graviton itself will not lead to a description of the path of a moving body. The gravitons in a field, like air molecules, might exert a force (if that is what they do) but the movement of gravitons will be governed by the dynamics created by surrounding bodies of mass. It is essentially a study of gravitational field theory that describes the motion. Although the existence of a graviton would be highly interesting as a component of the particle physics of the Universe, it is still mass that governs motion. The bigger the mass, the bigger the influence.
Is the graviton a messenger particle? Not any more than than a molecule caught up in a flow of air.

So, incline and contours determine the river flow, temperature and pressure determine the air flow and mass determines the gravitational "flow". General Relativity describes this flow. The particles of the flow (if they exist) are a different matter and that's an unintended pun. :)

Regards, Rob

[CraigS]

Yeah Rob;

Nicely put.

Not that I’m into Alex’s quest, but I think we all know the search for the source of gravity, really is the search to understand the nature and the origins of the universe.

The inclusion of all the fundamental forces under the one descriptive framework is clearly, the Holy Grail of Science.

Alex’s quest to understand what causes gravity is an extremely interesting one, (despite my teasing him about it on occasions). ;)

The types of Einstein, Bohr, et al knew this, which is why they spent time wrangling about Quantum Mechanics vs General Relativity. This continues today.

Somehow though, I don’t think this is going to be sorted out by pure thought experiments. I’d put my money on the LHC at CERN, although there is so much riding on the outcomes that this beastie may produce, it is difficult to imagine if anyone could admit that it may actually tell us nothing.

Nice “field” analogies though.

It is interesting that people seem to enjoy creating their own theories about them … there are so many of them, I’ve almost lost count ! Empirical data is the only way I can see to reduce the theory count, (as disappointing as that may be for the ‘speculative scientists’ amongst us).

Science is about asking questions eh ?
My feeling is that there may be no answers for a long while on this one.

Cheers & Rgds.

[Robh]

Hi Craig,

Here is a "clarification" of what a magnetic field is (from wikipedia: Magnetism) ...
"The phenomenon of magnetism is "mediated" by the magnetic field. An electric current or magnetic dipole creates a magnetic field, and that field, in turn, imparts magnetic forces on other particles that are in the fields."
Now does anyone really know what a magnetic field is? We have a cause and we have a field model to explain the effects.

Curiously, I can re-word the statement as follows ...
"The phenomenon of gravity is "mediated" by the gravitational field. A body of mass creates a gravitational field, and that field, in turn, imparts gravitational forces on other bodies that are in the fields."
Like magnetism, we have a cause and we have a field model to explain the effects.

Regards, Rob

[sjastro]

Mark,

In GR gravity is a fictitious force that acts only along the radial component. The forces acting on a particle moving along any of the 3D axes are not gravitational but are inertial forces such as tidal forces, centrifugal forces, corolis forces etc.

Regards

Steven

[sjastro]

Alex,

That's news to me.
Try thinking of space-time instead of space.

Here are some fundamental differences between space time and space.

(1) An object that is stationary in space moves in space time.
(2) An object that moves at a constant velocity in a straight line in space moves in a straight line in space time.
(3) An object that accelerates in a straight line in space moves in a curve in space time.
(4) An object in free fall in gravitational field moves in a straight line in space but in a curve in space time.
(5) The Earth's orbit is nearly circular in space has a helical orbit in space time.

The question as to why mass bends space-time is totally meaningless if
you notice that (3) and (4) are the same statements. This is the equivalence principle of GR at work.

Regards

Steven

[CraigS]

Hi Steven;

Great to have you 'back on the job' !

This is interesting for me.

I get that the question is not relevant in GR, however, when one attempts to ponder gravity from a quantum perspective, gravitons seem to appear. I think most would also be aware that attempting to incorporate gravity into the quantum world, then results in all of those famous problems which ultimately results in Grand Unification Theories (GUTs).

I find it fascinating that the various theories beyond GR, have been framed around attempting to address these problems in such a way as to explain everything from the quantum level up to, and including the bigger things more influenced by gravity. Field theories seem to also fall into a similar category. (I'm not quite not sure about this, yet).

I wonder about the influences this approach might have in shaping the initial foundations of the GUTs. It seems that there may well be artefacts lurking in these theories, originating from their initial premises.

I guess this is more a philosophical issue about the science theory creation process, as opposed to a technical one.

Interesting.

Cheers

[mjc]

Steven

Thanks for your reply - I think you've given me the nudge or clue that I was seeking. By viewing the problem in space-time I can see that at the event horizon the past light-cone of an observer would be outside the event horizon while the future light cone will lie within and the light-like edge boundary of the light cones will lie on the event horizon.

Your post led me onto this page - and both have helped considerably.

http://www.phy.syr.edu/courses/modules/LIGHTCONE/schwarzschild.html

I can't say that I immediately understand the tipping inwards of the light cone - but at least I have some handle to the answer.

Regards

Mark C.

[sjastro]

Mark,

In flat space the future light cone (and also the past light cone) forms a 45 degree angle with the time and spatial axes. This means the photon can move both in time and space from an observer's frame of reference.
The 45 degree angle tells us why photons travel in null geodesics and that the speed of light is the same for all inertial observers.

The situation becomes somewhat more complicated in gravitational fields. The closer a photon is to the event horizon the greater the gravitational redshift of the photon. The amount of tipping of the light cone is related to the gravitational redshift. A photon at the event horizon appears to be "stationary" to all observer's outside the event horizon. Each observer is still able to measure the passage of time but the photons do not appear to move spatially. An outgoing light cone edge that is vertical or parallel to the time axis means that the photon is spatially restricted to a particular value which in this case is the radius of the event horizon.
Inside the event horizon the light cone will never intercept the outside observer's world line hence it will never be seen.

Regards

Steven

[xelasnave]

Sorry I had to go out home where there is no electricity etc to check my carbon sinks;)
Thank you again Rohb, Craig and Steven for you help in attempting to understand the concept of space time.
Craig is correct about my interest in "the Theory of Everything" or the unification of all the forces and it is that interest that perhaps leaves me hunting for a messenger particle to make gravity work.
I recall Prof Hawking commenting that he received about three TOE,s per day at one stage so one could assume there are others interested the unification of the forces.
I understand what Rohb is driving at and such an approach is reasonable and yet I still believe that the operation of particles must at some level be able to explain the behavior of space time. Standing back and trying to follow the approaches of those interested in quantum mechanics and then those interested in general relativity it seems there is a difficulty in the two sides being reconciled. I dont think there needs to be any gap between the two in so far as I imagine that particles must causes the things we call properties of space time.... and I know this is probably offensive to both camps but remains my view.

I am starting to think that all fields must be a movement of particles that produce the field as opposed to a field causing the movement of particles... can I prove this ... no of course not ... I simply like the idea.
AND preference is not what guides science so it stands where it does as a mere idea.

Thanks again for starting a great thread Mark:thumbsup:
alex:):):)

[mjc]

Thanks Steven

I think I'm getting it. I'm glad I made the original post. Got to mull it over for it to settle but I do think I'm getting it.

Mark C.

[CraigS]

Alex;
Interesting. I find it fascinating that you keep gravitating (:lol:) back to a particles only view of it all, when there are so many other ways of looking at it.

At the moment, the particle view results in problems when considering the 'big picture', which is why mainstream scientists have developed the other concepts.

Why don't you follow that same path ? (I'm interested in why you are reluctant to move out of the hole made plainly visible by quantum mechanics' present boundaries. I mean, its your choice … so why not take the plunge ?).

Cheers

[xelasnave]

Craig a simple answer can be found in my ignorance of things in general:D.

I have done my best to understand General Relativity but it is not all that easy for me. At this point it seems to me to be complex geometry at work to describe something we dont understand but nevertheless works well:D ..so well in fact many think there is little need to ask any more of GR than what it has given us already.

I guess I like a particle approach because we deal with a physical unit.
Also something I have not said before is I find the concept of energy difficult and have to see it as an operation of very very small particles...even momentum I see a particle explanation
No doubt you "see" a wave as being able to operate in the absence of a particle background whereas I can not imagine a wave other than some form of particle movement say like an actual wave in water... I know in physics it is not seen that way.

Anyways as difficult as it is for me I hang on trying to learn more about the accepted physics and the kind folk here are always most helpful and extremely tolerant of my ignorance of much stuff. Its not a case of not coming around but more of I dont understand something others find in GR that I dont see.... but I continue to try rather than like many others simply throw it out trying to put in its place a different idea.
I never see the push gravity thing as interfering with GR as strange as that may seem..I think it is the particle flow I envisage that "bends" the geometric grid of space time ... but dont place too much on any of this as they are just ideas. AND given some of the seemingly wild ideas presented at the cutting edge of theoretical physics I dont feel my stuff is wild at all....but with no math one is branded as an idiot for radical views... I cant help that nor worry about folk who will be so critical at my attempts at original thought. To gain knowledge I dont care about what folk may think really.

I feel the key to understanding everything finally will probably come from ideas from both camps and maybe even ideas from the EU approach:shrug:.
AND as to difficulties with a quantum approach I think it simply means there is more work to do to make it all work.

I would like to think I am at least responsive to the knowledge folk here provide and if nothing else very grateful for same.
alex:):):)

[mjc]

Alex

I think we all try to justify things in terms of stuff that we are comfortable with.

I do it.

But I think it is important to try - and one can try and fail - to understand the other guy's perspective. I've learned stuff - in more than one walk of life - of how things work on the basis of constant re-engagement of something that should be beyond me and ended up in a better than expected understanding for someone without any grounding in the first place. It's like a child learning a language - with enough engagement a certain understanding is attained.

I don't pretend to be as competent as those I've learned from but I learn something with each engagement.

Mark C.

[xelasnave]

Yes indeed Mark.
It probably does not come across this way but I try to look at everything and understand what others see in it... It is clear I have doubts about stuff but I hang in because that is the only way to move forward. If one closes ones mind to settle upon one view I feel that is not helpful. The greatest minds on the planet wrestle with the sort of stuff we chat about here and we are very lucky to even get a look in...
I find this forum invaluable:thumbsup:.

alex:):):)

[mws]

My understanding of matter approaching the event horizon of a black hole is that will never actually enter the black hole, because of the extreme gravitational fields present, time will be slowed to such an extent that it would take an eternity to cross the horizon.

Michael

[CraigS]

Hi Michael;

Nice to meet you.

If matter falls towards a black hole, (due to the gravitational attraction forces caused by the density of matter inherent to a black hole), it will pass through the Event Horizon, (unnoticed by the falling matter), speed up to close to the speed of light, heat up, become 'spaghettified', (if the hole is a small one), and eventually decompose. Its remnants will become part of the black hole matter.

An observer watching the matter fall however, would, most likely, see the matter slow to a standstill, heat up and decompose into its fundamental constituents. The sub-atomic picture of the decomposition into its fundamental components changes, depending on the model's assumptions of sub-atomic physics.

Cheers & Rgds.