Layman's attempt at gravity

Q-reeus said:
That dismissive 'analysis' is from a profound ignorance and tells me you have never grasped what Yilmaz gravity entails and truly predicts.
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And I quote myself:
"I DON"T KNOW what gravity is. And even if, in a limited way, science can tell us a great deal about how it behaves, perhaps I don't really care about how it behaves, unless that also tells us the reason it does." Yilmaz tells me how it behaves, and misses by something as massive as a black hole, and I'm expected to ignore that and go for his detailed analysis?

Life is just, way too short for wasting time on theories of gravity that miss predicting something as profound as a black hole. There are better theories that explain more and black holes as a bonus.

Don't give me "metrics" when I'm looking for something less geometric. Inertialess space has no origin for a coordinate system, or for Euclidean geometry to be done. The universe is, thankfully, not an immutable Euclidean solid. Don't bother me with math that assumes it is.
 
danshawen said:
And I quote myself:
"I DON"T KNOW what gravity is. And even if, in a limited way, science can tell us a great deal about how it behaves, perhaps I don't really care about how it behaves, unless that also tells us the reason it does." Yilmaz tells me how it behaves, and misses by something as massive as a black hole, and I'm expected to ignore that and go for his detailed analysis?

Life is just, way too short for wasting time on theories of gravity that miss predicting something as profound as a black hole. There are better theories that explain more and black holes as a bonus.

Don't give me "metrics" when I'm looking for something less geometric. Inertialess space has no origin for a coordinate system, or for Euclidean geometry to be done. The universe is, thankfully, not an immutable Euclidean solid. Don't bother me with math that assumes it is.
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GR which predicts your beloved BH's is a purely metric theory, as is Yilmaz gravity mostly but not 'purely'. Are you feeling ok Dan?
 
Q-reeus said:
GR which predicts your beloved BH's is a purely metric theory, as is Yilmaz gravity mostly but not 'purely'. Are you feeling ok Dan?
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I know (that GR is also a 'metric' theory). But at least, it should work well enough to orbit a probe in the vicinity of a black hole without falling into its event horizon. If Yilmaz could simplify GPS calculations somewhere other than near a black hole, I suppose that would be of some utility as well.

Einstein was in a rush to beat Hilbert to publish a theory that worked. His first attempt many years before had been off by a factor of two. No one had "bet" against that either, but once upon a time, peer review, even of Einstein, actually worked. To finish GR before Hilbert presented his version, even Einstein needed to cut corners, the same workarounds Hilbert was playing with. The same ones having to do with driving a gravity 'stake' into inertialess space as the origin of a Euclidean coordinate system. That only works if you can either do the rest of your calculations before there is time for anything else to move, or assume you are driving that stake into the center of something so massive, that even if it moves, it doesn't move very much. The latter trade-off is what usually results in theories like GR, and also Yilmaz. The problem with the former trade-off, doing calculations before anything has time to move, like Special Relativity, is that it assumes the propagation of light to be the end of the road for trying to better understand the nature of time itself.

Feeling fine, but heavy into some grueling yard work in my retirement. Life's too short for doing that as well. Inefficiency is as impossible to escape as the gravity well of a supermassive black hole, which, paradoxically, Yilmaz' theory DOES predict. I do understand the distinction between those and a black hole that is only just massive enough to collapse.
 
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danshawen said:
Inefficiency is as impossible to escape as the gravity well of a supermassive black hole, which, paradoxically, Yilmaz' theory DOES predict. I do understand the distinction between those and a black hole that is only just massive enough to collapse.
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Tempted to ask for a clarification of that ambiguous string of words, but, given what has already transpired....pass.
But to clarify for your education; there are no horizons of any kind in Yilmaz gravity. No EH for compact objects. Nor for the cosmos. Nor any Rindler 'horizon' for accelerated observers. That may shock you, but it's actually a more consistent and rational physics than what GR offers.
 
Q-reeus said:
Tempted to ask for a clarification of that ambiguous string of words, but, given what has already transpired....pass.
But to clarify for your education; there are no horizons of any kind in Yilmaz gravity. No EH for compact objects. Nor for the cosmos. Nor any Rindler 'horizon' for accelerated observers. That may shock you, but it's actually a more consistent and rational physics than what GR offers.
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You were right. It was worth a second look. I'll bookmark it because some day, it may be handy.
 
Q-reeus said:
The OP seems to have lost interest in his own thread - or maybe just AWOL.
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Thank you for your input.

I tried to make things simply but it did not turn out that way.

My question is ...if gravity was a form of external pressure could one not expect the rotation curves we observe and remove the need for dark matter?
Further if things worked that way could gravity working this way explain what we call dark energy.

Thank you
Alex
 
origin said:
I do not know exactly why layman try to come up with alternative theories to physics.
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I would have thought it obvious.
If you are inclined to think about things you are likely to have ideas.
What is wrong with that?
I think about all sorts of things and I am happy that I do.
Many times I have had an idea which later someone follows thru upon having arrived at a similar conclusion as to possibilities and made the idea work...well I feel Happy that my idea worked.

A funny thing..with the push gravity I worked out how it could work that way only to find Le Sage had the idea centuries earlier...
I was happy...
I invented the electric motor when I was 11 years old ..I did not know they existed but very happy my idea worked.

And I know what I don't know and my limitations but why should that stop me from thinking about things.

I don't think for a moment I will change a thing but having thought about the two major problems for GR I think the problem is simply we believe gravity attracts ...why?
Offer an experiment that demonstrates there is a force of attraction...we start with that as an unfounded premise... Why only because everyone knows gravity attracts.
Anyways GR says neither attracts or pushes as far as I can tell.

But I like to think and whatever I hear about I have to think about what has been presented... I see no problem frankly...

Alex
 
Hey Alex, welcome back! I think you may have been away for a while? I haven't been around much either so maybe you've been here all along.

I agree that there is nothing wrong with thinking about all kinds of things. I don't know much about La Sage and Push Gravity other than some quick Google reading.

It does appear that it was pretty conclusively disproved about 100 years ago, right? Therefore, once you learned that La Sage had also come up with this long ago and it had been disproved years ago why do you now think it may be a valid theory?

Thinking is good but reading and thinking is even better isn't it? :)
 
Xelasnave.1947 said:
Thank you for your input.

I tried to make things simply but it did not turn out that way.

My question is ...if gravity was a form of external pressure could one not expect the rotation curves we observe and remove the need for dark matter?
Further if things worked that way could gravity working this way explain what we call dark energy.

Thank you
Alex
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(OK I see that Seattle has already touched on Le Sage 'push gravity'. Well anyway I already prepared the below so here it is.)

Not really. If I understand your drift right, that notion of external pressure as source of 'push gravity' had a name - LeSage (or Le Sage) gravity. In it's traditional form it was soon found that to explain lack of abberation and other factors, objects of any macroscopic size would instantly burn up from all the collisions of 'pressure particles' required by the theory. A modern version by a one Nigel Cook claims to have overcome that basic weakness by postulating 'off-shell' push particles that 'bounce' without dissipation involved.
However, gravity is not just about attraction between masses. Time dilation i.e. gravitational redshift in particular is an inherent feature of any modern theory of gravity according with well verified experimental evidence. No 'push gravity' theory can afaik rationally account for it. You really need a metric-type theory for that. Still, some researchers keep hoping:
https://en.wikipedia.org/wiki/Mechanical_explanations_of_gravitation
 
Q-reeus said:
(OK I see that Seattle has already touched on Le Sage 'push gravity'. Well anyway I already prepared the below so here it is.)

Not really. If I understand your drift right, that notion of external pressure as source of 'push gravity' had a name - LeSage (or Le Sage) gravity. In it's traditional form it was soon found that to explain lack of abberation and other factors, objects of any macroscopic size would instantly burn up from all the collisions of 'pressure particles' required by the theory. A modern version by a one Nigel Cook claims to have overcome that basic weakness by postulating 'off-shell' push particles that 'bounce' without dissipation involved.
However, gravity is not just about attraction between masses. Time dilation i.e. gravitational redshift in particular is an inherent feature of any modern theory of gravity according with well verified experimental evidence. No 'push gravity' theory can afaik rationally account for it. You really need a metric-type theory for that. Still, some researchers keep hoping:
https://en.wikipedia.org/wiki/Mechanical_explanations_of_gravitation
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Thank you for considering the proposition.
I don't want reasons why it won't work I want evidence proving I am right ..is that too much to ask. Smiley. LOL. Etc.

GR seems to avoid the possibility that there could be anything "mechanical" or a mechanism but surely there must be something ... It can't tell us why matter tells space to bend ...there must be more going on then we currently understand.
I should have an answer by tomorrow.
Again thanks nice finding you here.
Alex
 
Xelasnave.1947 said:
Thank you for considering the proposition.
I don't want reasons why it won't work I want evidence proving I am right ..is that too much to ask. Smiley. LOL. Etc.

GR seems to avoid the possibility that there could be anything "mechanical" or a mechanism but surely there must be something ... It can't tell us why matter tells space to bend ...there must be more going on then we currently understand.
I should have an answer by tomorrow.
Again thanks nice finding you here.
Alex
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And vice versa Alex. On checking back, I see my #71 was already covered earlier in #31 & #35. We both forgot I suppose.:frown:
I agree GR merely postulates a linkage between matter and curved spacetime without explaining how or why. Also it has a weakness in that in GR the curved spacetime of vacuum exterior to any matter source is formally devoid of any self-consistent energy-momentum content. Thus e.g. GW's are 'ghosts' that require mathematical sleight-of-hand to make 'physical' in that theory. Probably not best to talk here (again anyway - already was in 'conversations' with now-departed danshawen) re alternative theory with imo a better basis to it.
 
I probably should not even attempt this but,
question 1: does a massive object remain at the same spacetime coordinate?
question 2: does a gravity field extend the same in all directions or is it
If not, is it possible that the DeBroglie-Bohm Pilot wave may somehow be involved?

IOW, the size (not the mass) creates something like what is known in sailing as "hull-speed", where the length of a boat in water creates it's own trough, which is formed by the build up of a bow wave which creates a resistance and "traps" the boat in a permanent trough between the bow wave and the stern wave?

I guess this does not meet any of the current theories, but having experienced this phenomena myself while sailing, it just struck me that there seems to be a similarity in effect.
Hull speed or displacement speed is the speed at which the wavelength of the boat's bow wave (in displacement mode) is equal to the boat length. As boat speed increases from rest, the wavelength of the bow wave increases, and usually its crest-to-trough dimension (height) increases as well. When hull speed is reached, a boat in pure displacement mode will appear trapped in a trough behind its very large bow wave.
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https://en.wikipedia.org/wiki/Hull_speed
Froude number
In continuum mechanics, the Froude number (Fr) is a dimensionless number defined as the ratio of the flow inertia to the external field (the latter in many applications simply due to gravity). Named after William Froude (/ˈfruːd/;[1]), the Froude number is based on the speed–length ratio which he defined as ......
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https://en.wikipedia.org/wiki/Froude_number

I tried reading more about "complex planes", but the theories are far beyond my understanding.
Anyway, the OP title gave me the courage to throw my 2 cents worth into the mix.
 
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I can't recall what I have put in this thread already and to lazy to look so here is my take on gravity
Always found it problematic somehow Earth gravity goes to the moon, latches onto it and starts to drag it towards itself
Sure I understand gravity as a field not a rope but the mechanics make no sense (same like magnets - spooky at a distance)

But then I thought What if the gravity field could be compared to the atmosphere? Completely surrounding he Earth, becoming thinner the further out (that part at least is known to be correct)

Think of the gravity surrounding all the objects in the Universe as being sort of sponge like

Each field of gravity extending outward, becoming thinner as it goes, until it bumps up against another gravity field

Now we have a flattened area where the fields meet, a weakened neutral dead zone as the fields cancel each other out

The gravity fields of each object would look like a multi multi faceted object with the largest facet being between the two largest objects and hence the weakest dead neutral zone

The remaining objects surrounding the two largest objects would have their combined gravity field interaction facets pushing the two objects together through (into) the largest weakened dead neutral zone making it larger, weaker and deader which would accelerate the process

Thoughts - questions on the model if so inclined please

I will expand more later

It's 2:45 am here in Bali and I'm only on line for 2 reasons - a KMart bladder and no girlfriend who had to leave by car about 8 hours ago to return to Jakarta. Had a forced 2 days extra holiday due to active Bali volcano stopping flights

:)
 
Seattle said:
Hey Alex, welcome back!
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Thank you for your welcome back I went to live in the real world for a while.
Seattle said:
It does appear that it was pretty conclusively disproved about 100 years ago, right?
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Yes.
But as I understand things it never was a scientific theory in so far as it could not make any predictions.

Also I expect that it probably presents the notion of some sort of eather which at that point in time was losing favour as to recognise an ether would cause problems for SR and therefore GR.

Seattle said:
why do you now think it may be a valid theory?
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I don't throw stuff out on the basis it may become useful at some point.

However I am not married to the idea.

I am a simple minded guy and the fact that the concept in my mind offers a mechanism for gravity that I can conceptualise gives it an appeal.

GR as I understand is a co ordinate system and really should not be bothered by the mechanics of gravity.

I think at some level some sort of particle interaction would occur.

If attraction one particle would have to pass information to another...so let's consider attraction and ask how could that happen... Well when I thought about attraction I could not think of a mechanism...it would mean a two way communication which seemed unworkable whereas a simple Billiard ball interaction to me seemed probable.

That outlines my thoughts briefly.

However even with no math I could imagine that in such an environment galaxies would rotate as if being pushed from the outside such that their rotation will be different than if their gravity came from within.

In other words such a system would reflect observation and not require dark matter.

It is my view galaxies would fly apart if they rely on attraction unless there is much more matter than observations show.

Well GR says sure there is heaps of dark matter and that's why they don't fly apart and that's why the rotation curves are as observed.

So for GR to work to explain the unexpected rotation curves it must have dark matter... It is this necessity of requiring a new "matter" that leaves me uncomfortable and curious as to how it could be got rid of...

I list these thoughts simply to explain my thinking not to say Newtonian gravity or GR is wrong and look at me I have all the answers. I dont, I can not think of how you could fescribe this math wise...although maybe a similar approach to Hershels determination of energy output from the Sun....I just dont know ....But if dark matter can not be identified will we insist it is there because Newtonian gravity and GR tells us its there but we will never see it...or face the prospect we miss something which is fundamental...
I suggest a pressure system will fit the observations which is speculation but works from making the idea fit the observations rather than make the observations fit the idea.

I don't suggest our current theories are wrong but if there is so much dark matter in the Universe and many years of searching for it why is it we have not got a truck load of it in the lab.

Its sortta like the concept of god to me...sure you have many things that point to there being a god but just make him appear in person.
If you can't show him I doubt he exists...is that unreasonable?

Frankly the moment the models disagreed with the observations would have been the moment where I would have questioned the completeness of the model rather than say the model suggests matter we can't observe except by using the model.

I hope you take this as explanation of why I think about things than an opportunity to call me a crank.
And read ....that is all I do each day every day so I am not unaware of why such an approach will be jumped on as blasphemy.

Alex
 
Xelasnave.1947 said:
Thank you for your welcome back I went to live in the real world for a while.

Yes.
But as I understand things it never was a scientific theory in so far as it could not make any predictions.

Also I expect that it probably presents the notion of some sort of eather which at that point in time was losing favour as to recognise an ether would cause problems for SR and therefore GR.


I don't throw stuff out on the basis it may become useful at some point.

However I am not married to the idea.

I am a simple minded guy and the fact that the concept in my mind offers a mechanism for gravity that I can conceptualise gives it an appeal.

GR as I understand is a co ordinate system and really should not be bothered by the mechanics of gravity.

I think at some level some sort of particle interaction would occur.

If attraction one particle would have to pass information to another...so let's consider attraction and ask how could that happen... Well when I thought about attraction I could not think of a mechanism...it would mean a two way communication which seemed unworkable whereas a simple Billiard ball interaction to me seemed probable.

That outlines my thoughts briefly.

However even with no math I could imagine that in such an environment galaxies would rotate as if being pushed from the outside such that their rotation will be different than if their gravity came from within.

In other words such a system would reflect observation and not require dark matter.

It is my view galaxies would fly apart if they rely on attraction unless there is much more matter than observations show.

Well GR says sure there is heaps of dark matter and that's why they don't fly apart and that's why the rotation curves are as observed.

So for GR to work to explain the unexpected rotation curves it must have dark matter... It is this necessity of requiring a new "matter" that leaves me uncomfortable and curious as to how it could be got rid of...

I list these thoughts simply to explain my thinking not to say Newtonian gravity or GR is wrong and look at me I have all the answers. I dont, I can not think of how you could fescribe this math wise...although maybe a similar approach to Hershels determination of energy output from the Sun....I just dont know ....But if dark matter can not be identified will we insist it is there because Newtonian gravity and GR tells us its there but we will never see it...or face the prospect we miss something which is fundamental...
I suggest a pressure system will fit the observations which is speculation but works from making the idea fit the observations rather than make the observations fit the idea.

I don't suggest our current theories are wrong but if there is so much dark matter in the Universe and many years of searching for it why is it we have not got a truck load of it in the lab.

Its sortta like the concept of god to me...sure you have many things that point to there being a god but just make him appear in person.
If you can't show him I doubt he exists...is that unreasonable?

Frankly the moment the models disagreed with the observations would have been the moment where I would have questioned the completeness of the model rather than say the model suggests matter we can't observe except by using the model.

I hope you take this as explanation of why I think about things than an opportunity to call me a crank.
And read ....that is all I do each day every day so I am not unaware of why such an approach will be jumped on as blasphemy.

Alex
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Haha...I'll reserve the "crank" label for the true cranks. :)
 
Xelasnave.1947 said:
...I am a simple minded guy and the fact that the concept in my mind offers a mechanism for gravity that I can conceptualise gives it an appeal......I think at some level some sort of particle interaction would occur.....
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Well Alex, there is serious work on alternatives to GR and similar that do have elements of 'particle interaction' but in a far more subtle context that Le Sage, or say 'gravity-as-a-kind-of-sponge' ideas.
Currently the most prominent one - entropic gravity - is owing to Erik Verlinde:
https://www.forbes.com/sites/starts...atter-about-to-be-killed-by-emergent-gravity/
https://www.forbes.com/sites/starts...re-space-time-and-gravity-all-just-illusions/
https://www.wired.com/2017/01/case-dark-matter/

OTOH, clear back in 2011, this came out: https://arxiv.org/abs/1108.4161

None of above is new here btw - having been gone over in various earlier threads. And so the SF wheel keeps turning, turning....
 
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