This topic has been archived, and won't accept reply postings.
What makes stuff pull towards bigger stuff?
1
1
2
In reply to The Lemming:
Imagine a trampoline with a tennis ball on it, you stand in the middle, the tennis ball then rolls towards you. Now, the trampoline is the fabric of space-time, the tennis ball is a planet, you are the sun... you have the essence of the underpinnings of the theory of gravity.
Mass distorts the space-time that surrounds it. The force of gravity is resultant of these distortions.
Imagine a trampoline with a tennis ball on it, you stand in the middle, the tennis ball then rolls towards you. Now, the trampoline is the fabric of space-time, the tennis ball is a planet, you are the sun... you have the essence of the underpinnings of the theory of gravity.
Mass distorts the space-time that surrounds it. The force of gravity is resultant of these distortions.
Post edited at 11:06
In reply to A Longleat Boulderer:
And what makes up this fabric?
Serious question from a simpleton, as Isn't space empty?
or is this where the concept of dark matter fills the theory?
And what makes up this fabric?
Serious question from a simpleton, as Isn't space empty?
or is this where the concept of dark matter fills the theory?
1
In reply to The Lemming:
Absolutely nothing. It was only when Newton passed a law stating that everything should attract that things started to become as they are today. Prior to the Newton law, things were quite different.
> What makes stuff pull towards bigger stuff?
Absolutely nothing. It was only when Newton passed a law stating that everything should attract that things started to become as they are today. Prior to the Newton law, things were quite different.
1
In reply to The Lemming:
Nice piece here on how 'empty' space is not empty: http://scienceblogs.com/startswithabang/2012/07/26/empty-space-has-more-ene...
Nice piece here on how 'empty' space is not empty: http://scienceblogs.com/startswithabang/2012/07/26/empty-space-has-more-ene...
In reply to The Lemming:
Giant invisible rubber bands ("string theory" to those in the know [which does not include me]).
> What makes stuff pull towards bigger stuff?
Giant invisible rubber bands ("string theory" to those in the know [which does not include me]).
In reply to The Lemming:
Interestingly, 'empty space' is pretty much the only thing not permitted by the laws of quantum mechanics. I've not read Eric's link but think of it of a 'boiling sea' of particles popping in and out of existence for tiny fractions of a second at time and this happens everywhere all the time. So it's not only permitted but constantly happening in accordance with some strict rules. We refer to these particles as 'virtual particles'.
However, this isn't really much to do with what the 'fabric' actually is. Space-time fabric is the THING that we are on/in. Time and space are woven together in such a way to create this arena in which we and everything we know and have ever known can exist. I am sure someone more well versed in relativity theory can help here more than I can. However, as mentioned it's easiest visualised as a huge trampoline that we are all on and distort (but don't leave the surface of). But this is tough to translate this anology to a multidimentional universe I'll admit.
Interestingly, 'empty space' is pretty much the only thing not permitted by the laws of quantum mechanics. I've not read Eric's link but think of it of a 'boiling sea' of particles popping in and out of existence for tiny fractions of a second at time and this happens everywhere all the time. So it's not only permitted but constantly happening in accordance with some strict rules. We refer to these particles as 'virtual particles'.
However, this isn't really much to do with what the 'fabric' actually is. Space-time fabric is the THING that we are on/in. Time and space are woven together in such a way to create this arena in which we and everything we know and have ever known can exist. I am sure someone more well versed in relativity theory can help here more than I can. However, as mentioned it's easiest visualised as a huge trampoline that we are all on and distort (but don't leave the surface of). But this is tough to translate this anology to a multidimentional universe I'll admit.
Post edited at 11:26
In reply to A Longleat Boulderer:
What if it's on a treadmill?
> Imagine a trampoline with a tennis ball on it...
What if it's on a treadmill?
In reply to The Lemming:
I don't know what makes it work, but I climbing with a guy on whom I am sure gravity doesn't work! I always say he drinks anti-gravity juice!
I don't know what makes it work, but I climbing with a guy on whom I am sure gravity doesn't work! I always say he drinks anti-gravity juice!
In reply to abseil:
Then you end up with a very dizzy planet with a population much like the Russian's but not induced by Vodka.
Then you end up with a very dizzy planet with a population much like the Russian's but not induced by Vodka.
In reply to DubyaJamesDubya:
I'm frequently struck by how much posters know about obscure and/or difficult subjects - see the thread on fusion, for example, or ones on computering, plumbing, morality, etc, etc, etc.
> I'm impressed that you come to UKC for this information.
I'm frequently struck by how much posters know about obscure and/or difficult subjects - see the thread on fusion, for example, or ones on computering, plumbing, morality, etc, etc, etc.
In reply to DubyaJamesDubya:
And why should'nt I?
This site has some of the finest scientific minds in the country, one of whom was instrumental in finding the first planet in other solar systems. I'd say that this site was well placed to ask such grand questions as this where I can learn something.
> I'm impressed that you come to UKC for this information.
And why should'nt I?
This site has some of the finest scientific minds in the country, one of whom was instrumental in finding the first planet in other solar systems. I'd say that this site was well placed to ask such grand questions as this where I can learn something.
In reply to A Longleat Boulderer:
That's a handy way of imagining it happening, but I don't think it explains what makes it work.
In your illustration, what makes the tennis ball roll?
That's a handy way of imagining it happening, but I don't think it explains what makes it work.
In your illustration, what makes the tennis ball roll?
In reply to The Lemming:
Gravity is so interesting because all other physical forces (I think!! recalling A level physics from a dismayingly large number of years ago) are the result of interactions between particles, or more specifically subatomic particles, but there is no quantum explanation for gravity.
*awaits correction by boffins/people who actually know*
Gravity is so interesting because all other physical forces (I think!! recalling A level physics from a dismayingly large number of years ago) are the result of interactions between particles, or more specifically subatomic particles, but there is no quantum explanation for gravity.
*awaits correction by boffins/people who actually know*
In reply to skog:
Gravity
> That's a handy way of imagining it happening, but I don't think it explains what makes it work.
> In your illustration, what makes the tennis ball roll?
Gravity
In reply to skog:
What makes it work? Well, a bit more complex because a trampoline plane is a lot simple than space time however here's a bash at explaining as simply as poss...
Every object will continue moving through space-time in a straight line (as perceived by it) until an external force acts. Newton's first law (simplified slightly). For various reasons curved space-time 'feels like' a straight line and so an object will follow it. Therefore gravity is kind of just a result of obeying newton's 1st law ... and this ultimately leads to a curved 'real path' that we see when a planet orbits for example.
EDIT: or rather, more specifically curved space time IS the straightest path that the object can follow...
What makes it work? Well, a bit more complex because a trampoline plane is a lot simple than space time however here's a bash at explaining as simply as poss...
Every object will continue moving through space-time in a straight line (as perceived by it) until an external force acts. Newton's first law (simplified slightly). For various reasons curved space-time 'feels like' a straight line and so an object will follow it. Therefore gravity is kind of just a result of obeying newton's 1st law ... and this ultimately leads to a curved 'real path' that we see when a planet orbits for example.
EDIT: or rather, more specifically curved space time IS the straightest path that the object can follow...
Post edited at 11:53
In reply to A Longleat Boulderer:
Thanks.
I can see how that can explain gravity affecting the path taken by objects moving relative to each other, but what about when they start stationary relative to each other?
Thanks.
I can see how that can explain gravity affecting the path taken by objects moving relative to each other, but what about when they start stationary relative to each other?
In reply to The Lemming:
I don't think anybody knows.
Einstien's theory of General Relativity provides a theoretical context in which gravity emerges as a natural consequence of mass and energy curving the way our space-time is conceptually embedded in a higher dimensional space.
Quantum Mechanics provides a theoretical context (quantum electrodynamics) in which non-gravitational forces arise from the exchange of particles, acting as information carriers. Experiments show these particles to be real, although we've not got very far in understanding why we have the specific particles that we do.
There is a large gap in knowledge where these theories can't be made to meet in the middle. People have been trying for in excess of 50 years, we know that there must be some other theory that, under suitable conditions approximates both GR and QM.
Perhaps when this unified theory is found it will give an explanation, or interpretation, of how gravity works that a simple person such as myself can understand. Or perhaps we'll find that there is still another set of principles beyond our grasp...
I don't think anybody knows.
Einstien's theory of General Relativity provides a theoretical context in which gravity emerges as a natural consequence of mass and energy curving the way our space-time is conceptually embedded in a higher dimensional space.
Quantum Mechanics provides a theoretical context (quantum electrodynamics) in which non-gravitational forces arise from the exchange of particles, acting as information carriers. Experiments show these particles to be real, although we've not got very far in understanding why we have the specific particles that we do.
There is a large gap in knowledge where these theories can't be made to meet in the middle. People have been trying for in excess of 50 years, we know that there must be some other theory that, under suitable conditions approximates both GR and QM.
Perhaps when this unified theory is found it will give an explanation, or interpretation, of how gravity works that a simple person such as myself can understand. Or perhaps we'll find that there is still another set of principles beyond our grasp...
Post edited at 12:09
4
In reply to The Lemming:
Simple. It's because God designed it that way, otherwise the moon, sun, stars and planets wouldn't orbit the earth.
> What makes stuff pull towards bigger stuff?
Simple. It's because God designed it that way, otherwise the moon, sun, stars and planets wouldn't orbit the earth.
1
I'm hoping the OP has a plan to use this information to climb harder?
In reply to The Lemming:
Back when I was doing physics at school/college, people were talking in hushed voices about the idea of "Gravitons" some kind of sub-atomic particle/wave that excerted the gravitational force on objects in a similar way to photons exerting a force on the surface they hit - has this been debunked now? (not that I ever heard it as more than a theory)
Back when I was doing physics at school/college, people were talking in hushed voices about the idea of "Gravitons" some kind of sub-atomic particle/wave that excerted the gravitational force on objects in a similar way to photons exerting a force on the surface they hit - has this been debunked now? (not that I ever heard it as more than a theory)
In reply to Alyson:
They will only leave you at a higher level of confusion.
> *awaits correction by boffins/people who actually know*
They will only leave you at a higher level of confusion.
1
In reply to wintertree:
My theory is that 'our' universe uses 4 dimensions out of a possible wider number (n) dimensions. There are additional dimensions which exist in the same physical space we call the universe but to all intents and purposes they are invisible to us. However, we can note their effects.
Roughly 68% of the universe is dark energy, 27% dark matter, only 5% is 'matter' as we know it. In my model, dark matter is the same as our own matter, but it uses some of the other available dimensions so does not exist within our 4 dimensions. However, we know it has a gravitational pull because light bends round dark matter, therefore gravity must be a force which exists in our 4 dimensions but also in others at the same time. So the fabled 'graviton' exists, but only partly within our observable universe. We cannot find it because we can't access the other dimensions, though we can tell they are there.
What do you reckon, science folk?
> I don't think anybody knows.
> There is a large gap in knowledge where these theories can't be made to meet in the middle. People have been trying for in excess of 50 years, we know that there must be some other theory that, under suitable conditions approximates both GR and QM.
My theory is that 'our' universe uses 4 dimensions out of a possible wider number (n) dimensions. There are additional dimensions which exist in the same physical space we call the universe but to all intents and purposes they are invisible to us. However, we can note their effects.
Roughly 68% of the universe is dark energy, 27% dark matter, only 5% is 'matter' as we know it. In my model, dark matter is the same as our own matter, but it uses some of the other available dimensions so does not exist within our 4 dimensions. However, we know it has a gravitational pull because light bends round dark matter, therefore gravity must be a force which exists in our 4 dimensions but also in others at the same time. So the fabled 'graviton' exists, but only partly within our observable universe. We cannot find it because we can't access the other dimensions, though we can tell they are there.
What do you reckon, science folk?
In reply to Alyson:
It's all down to God.
I think we can establish the connection between gravity and time, by observing the changes over time in how gravity interacts with a woman's boobs.
One can also establish a phenomenon whereby two objects upon which gravity is having little effect, then cause a gravity-defying effect on an appendage owned by a third party observer.
It's all down to God.
I think we can establish the connection between gravity and time, by observing the changes over time in how gravity interacts with a woman's boobs.
One can also establish a phenomenon whereby two objects upon which gravity is having little effect, then cause a gravity-defying effect on an appendage owned by a third party observer.
In reply to Alyson:
Someone might chime in and correct me on this...
If there are other dimensions, we can and do "access" them - we exist at some point in every dimension there is. There could be a possibility that we exist in the presence of higher dimensions, and that we are unable to perceive it or to move in them. Various attempts to find a unified theory involve higher dimensions and as I understand things, the reason that we are unable to perceive them is that they extend over a very, very small range; so small that anything that exists, exists throughout that dimension. If they were larger, and they interacted with us in any way, they'd have a catastrophic effect on both gravity and light due to the way they dilute away from sources, so much so that nothing we know could exist. So as it stands, other dimensions could be real, but they wouldn't be big enough for anything to hide in them.
This sort of thing is the realm of string theory, and whilst it requires extra dimensions I think it precludes them being big enough to hide dark XYZ, and that if they were big enough to contain dark XYZ, that this would not be consistent with our observations of the galaxy.
> We cannot find it because we can't access the other dimensions, though we can tell they are there.
Someone might chime in and correct me on this...
If there are other dimensions, we can and do "access" them - we exist at some point in every dimension there is. There could be a possibility that we exist in the presence of higher dimensions, and that we are unable to perceive it or to move in them. Various attempts to find a unified theory involve higher dimensions and as I understand things, the reason that we are unable to perceive them is that they extend over a very, very small range; so small that anything that exists, exists throughout that dimension. If they were larger, and they interacted with us in any way, they'd have a catastrophic effect on both gravity and light due to the way they dilute away from sources, so much so that nothing we know could exist. So as it stands, other dimensions could be real, but they wouldn't be big enough for anything to hide in them.
This sort of thing is the realm of string theory, and whilst it requires extra dimensions I think it precludes them being big enough to hide dark XYZ, and that if they were big enough to contain dark XYZ, that this would not be consistent with our observations of the galaxy.
In reply to andrewmcleod:
That's one of the bad things about maths.
> Words are no good here - you need the maths to prove/show anything.
That's one of the bad things about maths.
In reply to Malcolm Tucker's Sweary Aunt:
If there was a god, she could only be female because that explains why men look so comical naked.
However... a female god would not allow breasts to be affected by gravity over time. Therefore: there is no god.
QED.
> It's all down to God.
> I think we can establish the connection between gravity and time, by observing the changes over time in how gravity interacts with a woman's boobs.
> One can also establish a phenomenon whereby two objects upon which gravity is having little effect, then cause a gravity-defying effect on an appendage owned by a third party observer.
If there was a god, she could only be female because that explains why men look so comical naked.
However... a female god would not allow breasts to be affected by gravity over time. Therefore: there is no god.
QED.
In reply to Alyson:
You, my dear, are a genius.
Have you sent this concise revelation to Coel and Tim? They've used 12336154821445484525484 words between them without reaching a conclusion at all.
You, my dear, are a genius.
Have you sent this concise revelation to Coel and Tim? They've used 12336154821445484525484 words between them without reaching a conclusion at all.
In reply to A Longleat Boulderer:
The trampoline only deforms in the first place because of gravity, and the tennis ball only starts rolling down the slope because of gravity.
No problem with any of that, except it doesn't answer the question about what makes it work in the first place....
That said, it's not really any different in nature to the question "what makes a proton attract an electron". Both involve forces that can't be seen.
> Imagine a trampoline with a tennis ball on it, you stand in the middle, the tennis ball then rolls towards you.
The trampoline only deforms in the first place because of gravity, and the tennis ball only starts rolling down the slope because of gravity.
> the trampoline is the fabric of space-time, the tennis ball is a planet, you are the sun... you have the essence of the underpinnings of the theory of gravity.
No problem with any of that, except it doesn't answer the question about what makes it work in the first place....
That said, it's not really any different in nature to the question "what makes a proton attract an electron". Both involve forces that can't be seen.
In reply to The Lemming:
It's one of those things that's really difficult to explain unless you're familiar with the mathematics involved. I struggled with it in my final year of a physics degree and eventually gave up.
We generally perceive the Universe to be a big 3 dimensional cartesian space with a fourth dimension of time running continuously from past to future. It's an approximation that makes sense in our day to day world where we don't deal with extremes of speed of mass.
In truth, space and time can't be considered as separate things but are actually the same thing, and are interchangable with one another. The presence of mass or energy (which are also flip sides of the same coin, E=mc^2) distorts this space-time. The easiest visual analogy is the large ball creating an indent in a taught rubber sheet, just try and think of that 2D example scaled up to 4 dimensions.
There are strange effects of this which Einstein's theory predicted. One is that 2 bodies at different heights in a gravitational field will experience time at a different rate compared to one another. This has been measured and confirmed by sending atomic clocks around the earth on a plane, and comparing it with a static clock on the ground. The Russian cosmonaut Sergei Krikalev has spent so much time in orbit that he has aged 0.02 seconds less compared to a hypothetical identical twin who remained on Earth!
See also:
-Black holes
-Neutron stars
-Gravitational lensing
-Special relativity (easy)
-General relativity (HARD!)
etc
It's one of those things that's really difficult to explain unless you're familiar with the mathematics involved. I struggled with it in my final year of a physics degree and eventually gave up.
We generally perceive the Universe to be a big 3 dimensional cartesian space with a fourth dimension of time running continuously from past to future. It's an approximation that makes sense in our day to day world where we don't deal with extremes of speed of mass.
In truth, space and time can't be considered as separate things but are actually the same thing, and are interchangable with one another. The presence of mass or energy (which are also flip sides of the same coin, E=mc^2) distorts this space-time. The easiest visual analogy is the large ball creating an indent in a taught rubber sheet, just try and think of that 2D example scaled up to 4 dimensions.
There are strange effects of this which Einstein's theory predicted. One is that 2 bodies at different heights in a gravitational field will experience time at a different rate compared to one another. This has been measured and confirmed by sending atomic clocks around the earth on a plane, and comparing it with a static clock on the ground. The Russian cosmonaut Sergei Krikalev has spent so much time in orbit that he has aged 0.02 seconds less compared to a hypothetical identical twin who remained on Earth!
See also:
-Black holes
-Neutron stars
-Gravitational lensing
-Special relativity (easy)
-General relativity (HARD!)
etc
In reply to Malcolm Tucker's Sweary Aunt:
They have reached two equal and opposite conclusions. Their impasse is the only thing holding the universe in balance.
> Have you sent this concise revelation to Coel and Tim? They've used 12336154821445484525484 words between them without reaching a conclusion at all.
They have reached two equal and opposite conclusions. Their impasse is the only thing holding the universe in balance.
In reply to The Lemming:
Jusy got back from walking the dog in the rain and I have been musing some more about this. I've also read the posts, one of which suggests that we start conversing in a language which is totally foreign to me, maths.
Lets stick to words, and the smaller the better.
My first question is about space.
Here on planet earth, we have three substances of solid, liquid and gas. I am guessing that space is, not empty, but rather a substance in which everything else is suspended?
Could this substance be crudely described as time-space because we can't really observe it?
Also from my non scientific education of cause and effect. For something to move it has to push away from something. I know there is a sciency correct answer but this is the level that I can comprehend. So, in space for stuff to move a rocket or propulsion system has to push against something, right, or it would not be able to move?
Doesn't this explain that space is not empty because stuff has to push against stuff in order to move in the opposite direction?
I take it that we can explain gravity and can demonstrate that gravity exists, but we can't explain what makes gravity work?
And I'm guessing that we will need to create bigger and bigger instruments with more and more energy required to discover smaller and smaller substances/explanations?
Jusy got back from walking the dog in the rain and I have been musing some more about this. I've also read the posts, one of which suggests that we start conversing in a language which is totally foreign to me, maths.
Lets stick to words, and the smaller the better.
My first question is about space.
Here on planet earth, we have three substances of solid, liquid and gas. I am guessing that space is, not empty, but rather a substance in which everything else is suspended?
Could this substance be crudely described as time-space because we can't really observe it?
Also from my non scientific education of cause and effect. For something to move it has to push away from something. I know there is a sciency correct answer but this is the level that I can comprehend. So, in space for stuff to move a rocket or propulsion system has to push against something, right, or it would not be able to move?
Doesn't this explain that space is not empty because stuff has to push against stuff in order to move in the opposite direction?
I take it that we can explain gravity and can demonstrate that gravity exists, but we can't explain what makes gravity work?
And I'm guessing that we will need to create bigger and bigger instruments with more and more energy required to discover smaller and smaller substances/explanations?
In reply to Nutkey:
Well, yes, but I cannot think of an easier analogy for the deformation of spacetime and subsequent gravitational attraction. Once it's understood deformation of ST is key then you can start to talk about curves through ST being the straightest path and objects sticking to this in accordance with Newton1.
That's what I was trying to do!
> The trampoline only deforms in the first place because of gravity, and the tennis ball only starts rolling down the slope because of gravity.
Well, yes, but I cannot think of an easier analogy for the deformation of spacetime and subsequent gravitational attraction. Once it's understood deformation of ST is key then you can start to talk about curves through ST being the straightest path and objects sticking to this in accordance with Newton1.
That's what I was trying to do!
Post edited at 14:22
In reply to The Lemming:
Back in the day when I studied fizzix, our best lecturer spent a while on this, and informed us that the word 'magic' is just about as reliable as any other definition we could come up with.
I like it, it's amazing what we don't know yet.
I should add in case I start sounding credible, that I then preceeded to drop out, maybe that was something to do with the same magic...
Back in the day when I studied fizzix, our best lecturer spent a while on this, and informed us that the word 'magic' is just about as reliable as any other definition we could come up with.
I like it, it's amazing what we don't know yet.
I should add in case I start sounding credible, that I then preceeded to drop out, maybe that was something to do with the same magic...
In reply to skog:
Remember that though they are stationary relative to one another they will have a trajectory through space-time (read: relative to something else, another planet, galaxy, whatever), and therefore the relative distortions of space time affect what is the straightest line (geodesic) of travel for each... the curves move together.
> I can see how that can explain gravity affecting the path taken by objects moving relative to each other, but what about when they start stationary relative to each other?
Remember that though they are stationary relative to one another they will have a trajectory through space-time (read: relative to something else, another planet, galaxy, whatever), and therefore the relative distortions of space time affect what is the straightest line (geodesic) of travel for each... the curves move together.
Post edited at 14:29
In reply to Alyson:
How large was your sample? Was it statistically significant?
I fear you are misunderstanding the application of relativity theory to breasts. Gravity is a constant, it is the breasts that change.
> If there was a god, she could only be female because that explains why men look so comical naked.
How large was your sample? Was it statistically significant?
> However... a female god would not allow breasts to be affected by gravity over time. Therefore: there is no god.
I fear you are misunderstanding the application of relativity theory to breasts. Gravity is a constant, it is the breasts that change.
In reply to Simon4:
No no, that's not the theory of relativity... that's the theory of relative titty.
<I'll get my coat>
> I fear you are misunderstanding the application of relativity theory to breasts. Gravity is a constant, it is the breasts that change.
No no, that's not the theory of relativity... that's the theory of relative titty.
<I'll get my coat>
1
In reply to A Longleat Boulderer:
Ah, that seems like it makes sense (as far as I can follow!)
Would that then mean that in a hypothetical universe containing only two objects with mass, stationary relative to each other, these objects would not begin falling together?
Ah, that seems like it makes sense (as far as I can follow!)
Would that then mean that in a hypothetical universe containing only two objects with mass, stationary relative to each other, these objects would not begin falling together?
In reply to Simon4:
You are not all wildly different you know. Same basic things in same basic places. All amusing.
Gravity is not a constant, it's inversely proportional to the square of the distance between the objects. Fool.
> How large was your sample? Was it statistically significant?
You are not all wildly different you know. Same basic things in same basic places. All amusing.
> I fear you are misunderstanding the application of relativity theory to breasts. Gravity is a constant, it is the breasts that change.
Gravity is not a constant, it's inversely proportional to the square of the distance between the objects. Fool.
In reply to The Lemming:
Newtons 3rd law says every reaction has an equal and opposite reaction. So when a rocket fires X amount of thrust in one direction, it gets pushed X amount in the other. It's not actually pushing off anything.
I vaguely remember being told that if you stood on a skateboard and lobbed bricks in one direction, you would move in the other. I'm tempted to try it on my chair at work......
Newtons 3rd law says every reaction has an equal and opposite reaction. So when a rocket fires X amount of thrust in one direction, it gets pushed X amount in the other. It's not actually pushing off anything.
I vaguely remember being told that if you stood on a skateboard and lobbed bricks in one direction, you would move in the other. I'm tempted to try it on my chair at work......
In reply to The Lemming:
Well, I never..
A UKC thread which is educational, funny, witty but somehow has managed not to decend into a slagging match.
I'm impressed.
I too hope this helps us all to climb better now we understand Gravity better
Well, I never..
A UKC thread which is educational, funny, witty but somehow has managed not to decend into a slagging match.
I'm impressed.
I too hope this helps us all to climb better now we understand Gravity better
1
In reply to The Lemming:
There are further states of matter and there is 'stuff' in 'space', it's just generally a bit more spaced out than we're used to.
A rocket doesn't need to be passing through something in order to generate thrust, the thing it's pushing on is the mass it's ejecting, its propellant.
Can't help you with gravity, it's beyond the grasp of my meager intellect.
jk
> Here on planet earth, we have three substances of solid, liquid and gas. I am guessing that space is, not empty, but rather a substance in which everything else is suspended?
> Could this substance be crudely described as time-space because we can't really observe it?
> Could this substance be crudely described as time-space because we can't really observe it?
There are further states of matter and there is 'stuff' in 'space', it's just generally a bit more spaced out than we're used to.
> Also from my non scientific education of cause and effect. For something to move it has to push away from something. I know there is a sciency correct answer but this is the level that I can comprehend. So, in space for stuff to move a rocket or propulsion system has to push against something, right, or it would not be able to move?
A rocket doesn't need to be passing through something in order to generate thrust, the thing it's pushing on is the mass it's ejecting, its propellant.
> I take it that we can explain gravity and can demonstrate that gravity exists, but we can't explain what makes gravity work?
Can't help you with gravity, it's beyond the grasp of my meager intellect.
jk
In reply to John Stainforth:
Oh I've no idea about numbers, I'm all about making unilateral pronouncements with my arms folded
> Scientists are nowhere near as definite and sure of their numbers as you are!
Oh I've no idea about numbers, I'm all about making unilateral pronouncements with my arms folded
In reply to The Lemming:
Is gravity a side effect of something?
And is it getting weaker or is it a constant?
Is gravity a side effect of something?
And is it getting weaker or is it a constant?
In reply to The Lemming:
We used to think this. They called it the 'Luminiferous Aether', a substance that filled the universe like water in a fish bowl but with several crazy properties. We showed through experimentation that actually this didn't exist. Lots on Wikipedia about this.
Space is actually full of particles popping in to existence with their 'anti particle', identical but with opposite charge... they travel together and then meet again and disappear (annihilate). Basically the universe can borrow a certain amount of energy as long as it gives it back again in a set amount of time (particles coming back together and 'disappearing'). Interestingly this is the basis of the mechanism that Hawking described for 'black hole radiation': particles appearing to radiate from black holes- this was a conundrum because black holes are supposed to swallow everything including light... how could things be coming so uniformly from their direction? He postulated that when particles pop in to existence at the perfect distance from a black hole, one gets sucked in and the other is just far enough away to escape ... it carris on its merry way with nothing to 'annihilate' with and we see it. Gloriously simple idea.
Space-time is more than this though because it includes the fourth dimension of time. So not only is it where the game of life is played, it's also when.
It's not actually pushing against something that does this. As others have said, every action has an equal and opposite reaction. It's why you will struggle to spin yourself on a (well lubricated) computer by just waving your arms. Each time you bring them back you undo the progress you made from the last wave. Each action has an equal and opposite reaction.
Unfortunately not, as above. For simplicities sake, you can consider space essentially empty. The science behind the first bit i talked about (particles popping in and out) is very involved. It's probably easier to assume it empty.
We have a good idea, as above- bent space time and objects following straight lines. However we don't know why it's so weak compared to electromagnetic forces for example. The fact you can't fall through your chair show just how easily the repulsive electromagnic forces of the particles in your chair and arse can overcome the pull of gravity and support you. Gravity is stupidly weak.
Yup. To see smaller things we need higher energies.
> Here on planet earth, we have three substances of solid, liquid and gas. I am guessing that space is, not empty, but rather a substance in which everything else is suspended?
We used to think this. They called it the 'Luminiferous Aether', a substance that filled the universe like water in a fish bowl but with several crazy properties. We showed through experimentation that actually this didn't exist. Lots on Wikipedia about this.
Space is actually full of particles popping in to existence with their 'anti particle', identical but with opposite charge... they travel together and then meet again and disappear (annihilate). Basically the universe can borrow a certain amount of energy as long as it gives it back again in a set amount of time (particles coming back together and 'disappearing'). Interestingly this is the basis of the mechanism that Hawking described for 'black hole radiation': particles appearing to radiate from black holes- this was a conundrum because black holes are supposed to swallow everything including light... how could things be coming so uniformly from their direction? He postulated that when particles pop in to existence at the perfect distance from a black hole, one gets sucked in and the other is just far enough away to escape ... it carris on its merry way with nothing to 'annihilate' with and we see it. Gloriously simple idea.
> Could this substance be crudely described as time-space because we can't really observe it?
Space-time is more than this though because it includes the fourth dimension of time. So not only is it where the game of life is played, it's also when.
> Also from my non scientific education of cause and effect. For something to move it has to push away from something. I know there is a sciency correct answer but this is the level that I can comprehend. So, in space for stuff to move a rocket or propulsion system has to push against something, right, or it would not be able to move?
It's not actually pushing against something that does this. As others have said, every action has an equal and opposite reaction. It's why you will struggle to spin yourself on a (well lubricated) computer by just waving your arms. Each time you bring them back you undo the progress you made from the last wave. Each action has an equal and opposite reaction.
> Doesn't this explain that space is not empty because stuff has to push against stuff in order to move in the opposite direction?
Unfortunately not, as above. For simplicities sake, you can consider space essentially empty. The science behind the first bit i talked about (particles popping in and out) is very involved. It's probably easier to assume it empty.
> I take it that we can explain gravity and can demonstrate that gravity exists, but we can't explain what makes gravity work?
We have a good idea, as above- bent space time and objects following straight lines. However we don't know why it's so weak compared to electromagnetic forces for example. The fact you can't fall through your chair show just how easily the repulsive electromagnic forces of the particles in your chair and arse can overcome the pull of gravity and support you. Gravity is stupidly weak.
> And I'm guessing that we will need to create bigger and bigger instruments with more and more energy required to discover smaller and smaller substances/explanations?
Yup. To see smaller things we need higher energies.
Post edited at 16:43
In reply to The Lemming:
They're explaining gravity on CBBC right now, with Brian Cox. I think it might be the right level for you
They're explaining gravity on CBBC right now, with Brian Cox. I think it might be the right level for you
In reply to Stig:
I realise the discussion has moved on a bit, but a nice way I was taught to think of the "what makes them move question" is that everything is moving at a fixed speed in space-time. If you're stationary in space you're only moving in time, if you're moving in space you're going a little slower in time such that your overall space-time speed stays the same. So when gravity curves space time such that your geodesic (fancy word for shortest path) is no longer just pointing in the time direction, but has a spatial component, you appear to start moving in space.
The total speed remaining the same effect also explains why the passage of time is different for those moving at different speeds.
For those in the know this is effectively just saying that the length of your velocity four-vector is invariant under Lorentz transformations.
I realise the discussion has moved on a bit, but a nice way I was taught to think of the "what makes them move question" is that everything is moving at a fixed speed in space-time. If you're stationary in space you're only moving in time, if you're moving in space you're going a little slower in time such that your overall space-time speed stays the same. So when gravity curves space time such that your geodesic (fancy word for shortest path) is no longer just pointing in the time direction, but has a spatial component, you appear to start moving in space.
The total speed remaining the same effect also explains why the passage of time is different for those moving at different speeds.
For those in the know this is effectively just saying that the length of your velocity four-vector is invariant under Lorentz transformations.
1
In reply to A Longleat Boulderer:
It fascinates me that we've moved to realising that thrust is not pushing off of space, and that in doing so our problems have expanded to encompass "where does inertia come from?", and that some of the theories of inertial mass involve interaction with distant matter pushing on objects.
I imagine that answering "what is inertia" would answer a lot more questions to boot.
> It's not actually pushing against something that does this.
It fascinates me that we've moved to realising that thrust is not pushing off of space, and that in doing so our problems have expanded to encompass "where does inertia come from?", and that some of the theories of inertial mass involve interaction with distant matter pushing on objects.
I imagine that answering "what is inertia" would answer a lot more questions to boot.
Post edited at 17:32
In reply to The Lemming:
The gravity on earth is the result of its rotation, if the earth stopped rotating there would be no gravity.
The gravity on earth is the result of its rotation, if the earth stopped rotating there would be no gravity.
In reply to Alyson:
The distance in time, or do you more accurately mean the distance in spacetime? Or the time in spacetime?
At any given distance, it is constant.
Possibly senile, not quite the same. Breasts are not the only things that lose their crispness with time you know. Or should that be with spacetime, I've forgotten. (When you cannot even remember what it is you are supposed to be remembering, you know things are really bad. Or rather, you probably don't.)
> Gravity is not a constant, it's inversely proportional to the square of the distance between the objects.
The distance in time, or do you more accurately mean the distance in spacetime? Or the time in spacetime?
At any given distance, it is constant.
> Fool
Possibly senile, not quite the same. Breasts are not the only things that lose their crispness with time you know. Or should that be with spacetime, I've forgotten. (When you cannot even remember what it is you are supposed to be remembering, you know things are really bad. Or rather, you probably don't.)
In reply to John Simpson:
The moon rotates around the earth and keeps the same face to the earth, yet it has gravity.
What if the earth rotated around the sun and kept the same face/aspect to the sun, would the earth still have no gravity?
> The gravity on earth is the result of its rotation, if the earth stopped rotating there would be no gravity.
The moon rotates around the earth and keeps the same face to the earth, yet it has gravity.
What if the earth rotated around the sun and kept the same face/aspect to the sun, would the earth still have no gravity?
In reply to Simon4:
It now sounds very much as if you're getting breasts and lettuces mixed up.
> Breasts are not the only things that lose their crispness with time you know.
It now sounds very much as if you're getting breasts and lettuces mixed up.
In reply to The Lemming:
Iv spent a fortune on physics books supposedly for the lay person and the only one I found that made at least a little sense to me was the elegant universe by Brian Greene. (Though I admit I'm probably lucky if I understand a quarter of it) I should probably say that the theories may well be out of date now but the physics buffs on here may know that better. Do any of them know of an idiots guide to the theory of everything?
Iv spent a fortune on physics books supposedly for the lay person and the only one I found that made at least a little sense to me was the elegant universe by Brian Greene. (Though I admit I'm probably lucky if I understand a quarter of it) I should probably say that the theories may well be out of date now but the physics buffs on here may know that better. Do any of them know of an idiots guide to the theory of everything?
In reply to julesp:
I did start to read "Why E = MC2", by the ubiquitous Brian Cox. It wasn't terribly easy to follow though some of it was quite illuminating, it also seemed to provoke scathing remarks from those more informed about the subject. But that may have just been the "tall poppy" syndrome.
I did start to read "Why E = MC2", by the ubiquitous Brian Cox. It wasn't terribly easy to follow though some of it was quite illuminating, it also seemed to provoke scathing remarks from those more informed about the subject. But that may have just been the "tall poppy" syndrome.
In reply to The Lemming:
This is nonsense, the mass of something gives it it's gravity because mass distorts space time. rotation has nothing to do with it. Also the moon does not go around the earth, they actually orbit each other but as the earth is so much more massive the centre point for this orbit is well inside the earth.
> The moon rotates around the earth and keeps the same face to the earth, yet it has gravity.
> What if the earth rotated around the sun and kept the same face/aspect to the sun, would the earth still have no gravity?
This is nonsense, the mass of something gives it it's gravity because mass distorts space time. rotation has nothing to do with it. Also the moon does not go around the earth, they actually orbit each other but as the earth is so much more massive the centre point for this orbit is well inside the earth.
In reply to The Lemming:
I think JS was joking about Earth having gravity because it is spinning, that's not the case, in fact it spinning reduces our perception of gravity on the surface. Things have gravity between them, ie. are attracted to each other, because of their mass... which doesn't answer your question, and which puzzles me too. Reading this thread it seems clear that no one posting here knows the answer really and as there are several probably no one can answer your question in simple terms... all the talk of space time etc isn't answering it's just moving goal posts.
When people have answered what is gravity maybe they could answer "What is magnetism?" I've never found an answer to that either.
I think JS was joking about Earth having gravity because it is spinning, that's not the case, in fact it spinning reduces our perception of gravity on the surface. Things have gravity between them, ie. are attracted to each other, because of their mass... which doesn't answer your question, and which puzzles me too. Reading this thread it seems clear that no one posting here knows the answer really and as there are several probably no one can answer your question in simple terms... all the talk of space time etc isn't answering it's just moving goal posts.
When people have answered what is gravity maybe they could answer "What is magnetism?" I've never found an answer to that either.
In reply to Bruce Hooker:
I think the point is that nobody in the world really knows the answer either.
People have a better handle on that one. Answering your question is not so easy - a few snappy words may convey a perception of understanding but not real understanding. You can ask Brian Cox for that. The closest I could get is "Magnetism is our description for the forces that emerge, as a result of special relativity, between electric charges that are moving with respect to each other." Apparently non-moving objects can have a magnetic force because the charged electrons are moving around inside the material. I recall someone stating that "Magnetism is electrostatic force reflected in relativity's mirror" but that mixes to many metaphors for my liking.
> Reading this thread it seems clear that no one posting here knows the answer really
I think the point is that nobody in the world really knows the answer either.
> When people have answered what is gravity maybe they could answer "What is magnetism?"
People have a better handle on that one. Answering your question is not so easy - a few snappy words may convey a perception of understanding but not real understanding. You can ask Brian Cox for that. The closest I could get is "Magnetism is our description for the forces that emerge, as a result of special relativity, between electric charges that are moving with respect to each other." Apparently non-moving objects can have a magnetic force because the charged electrons are moving around inside the material. I recall someone stating that "Magnetism is electrostatic force reflected in relativity's mirror" but that mixes to many metaphors for my liking.
Post edited at 19:10
In reply to The Lemming:
If you have to ask that question you simply won't understand my explanation - will you?
If you have to ask that question you simply won't understand my explanation - will you?
In reply to wintertree:
Sorry, but that doesn't make me any clearer on magnetism... maybe I'm asking for too much? I'm looking for what distinguishes it from electricity. I can see they are related but then this is not entirely true as lumps of iron can be magnetic and there's no electricity involved.
But what about gravity first, or rather the more general question of the force of attraction between two objects, any sort of objects and only attraction, never repulsive as for magnetism sometimes. Or maybe all this is related? Or not? It seems that we know how to use these various forces but cannot really explain them.
Sorry, but that doesn't make me any clearer on magnetism... maybe I'm asking for too much? I'm looking for what distinguishes it from electricity. I can see they are related but then this is not entirely true as lumps of iron can be magnetic and there's no electricity involved.
But what about gravity first, or rather the more general question of the force of attraction between two objects, any sort of objects and only attraction, never repulsive as for magnetism sometimes. Or maybe all this is related? Or not? It seems that we know how to use these various forces but cannot really explain them.
In reply to Bruce Hooker:
Me
Each atom of iron is a nucleus with positive electrical charge, and electrons orbiting the nucleus with negative electrical charge. That means they are whirling around the nucleus and moving. The moving charge on each atom of iron makes a magnetic force, and when the electrons on all the atoms move the same way, those forces add up to make a big magnet. There's a dozen different simplifications in that description, but that's it.
Electricity and magnetism can be described (by theory) and their origins explained very well, and are well understood.
Gravity can be well described by theory on local scales, with big questions at large scales that require either a new theory (MoND etc.) or new stuff (dark matter, energy.). As well as there being potential flaws in our description of gravity, we can not yet explain its origin.
> [How can] lumps of iron can be magnetic and there's no electricity involved.
Me
> Apparently non-moving objects can have a magnetic force because the charged electrons are moving around inside the material.
Each atom of iron is a nucleus with positive electrical charge, and electrons orbiting the nucleus with negative electrical charge. That means they are whirling around the nucleus and moving. The moving charge on each atom of iron makes a magnetic force, and when the electrons on all the atoms move the same way, those forces add up to make a big magnet. There's a dozen different simplifications in that description, but that's it.
> Or maybe all this is related? Or not? It seems that we know how to use these various forces but cannot really explain them.
Electricity and magnetism can be described (by theory) and their origins explained very well, and are well understood.
Gravity can be well described by theory on local scales, with big questions at large scales that require either a new theory (MoND etc.) or new stuff (dark matter, energy.). As well as there being potential flaws in our description of gravity, we can not yet explain its origin.
In reply to A Longleat Boulderer:
Thanks for that explanation. Made a lot of sense.
Can you explain space-time in such simple terms?
Thanks for that explanation. Made a lot of sense.
Can you explain space-time in such simple terms?
In reply to wintertree:
Ok, so magnetism is caused by electricity - at school we learnt it the other way round as we started looking at magnetism and playing with magnets and iron filings before we studied electricity and then electromagnetism - but, at the risk of being dense, that doesn't explain what magnetism actually is... does it?
Ok, so magnetism is caused by electricity - at school we learnt it the other way round as we started looking at magnetism and playing with magnets and iron filings before we studied electricity and then electromagnetism - but, at the risk of being dense, that doesn't explain what magnetism actually is... does it?
In reply to The Lemming:
Gravity definitely increases when I climb outdoors.
But the two atomic clocks - these measure time by a predictable rate of radioactive decay. If the clock travelling at high speed registers time more slowly, maybe the rate of decay just isn't as constant as we think?
Gravity definitely increases when I climb outdoors.
But the two atomic clocks - these measure time by a predictable rate of radioactive decay. If the clock travelling at high speed registers time more slowly, maybe the rate of decay just isn't as constant as we think?
In reply to SiGregory:
The point these 2 clocks illustrate is that the speed of light is the only absolute constant. All other things are changeable, including time (and therefore also including the rate of decay, which is a measure of time).
> But the two atomic clocks - these measure time by a predictable rate of radioactive decay. If the clock travelling at high speed registers time more slowly, maybe the rate of decay just isn't as constant as we think?
The point these 2 clocks illustrate is that the speed of light is the only absolute constant. All other things are changeable, including time (and therefore also including the rate of decay, which is a measure of time).
In reply to Bruce Hooker:
They are different facets of the same thing, or reflections, or aspects.
That all depends on what you're willing to take as an explanation. Taken as a series of mathematical equations it's a crystal clear explanation to someone who is versed in that language. To explain it to the satisfaction of an arbitrary individual, what do you want? Precise mathematical theory? Some words that hit a sympathetic resonance with your perception of the world, yet may not be scientifically accurate? Some words that convey the gist of it without the details?
I've given some suggestions - you've not said why they don't explain it to you. Here's some more:
1) Magnetism is the force between magnets.
2) Magnetism a force that arises from moving charges, which may be caused by using a battery to move a current down a wire, or which may be caused by the tiny electric currents in every atom of some materials coming into alignment so that the tiny magnetic force of each atom aligns.
3) Magnetism does not exist and is a convenient description we assign to the force that arrises when considering the electrostatic interaction of charges moving with respect to one another under special relativity.
4) Magnetism is electrostatics under Lorentz transformations.
Take your pick. Some of them may not be satisfying explanations, but if a dozen words could convey the entire content of electrostatics and special relativity in sufficient detail to be a fully convincing explanation, we wouldn't have invented mathematics
I would have hoped my explanation that magnetism arises from moving electric charges, and that electrons are charges moving around in atoms, and that in iron these little charges can all align making a big, strong field, was a decent middle ground explanation. I guess not.
> Ok, so magnetism is caused by electricity - at school we learnt it the other way round as we started looking at magnetism and playing with magnets and iron filings
They are different facets of the same thing, or reflections, or aspects.
> but, at the risk of being dense, that doesn't explain what magnetism actually is... does it?
That all depends on what you're willing to take as an explanation. Taken as a series of mathematical equations it's a crystal clear explanation to someone who is versed in that language. To explain it to the satisfaction of an arbitrary individual, what do you want? Precise mathematical theory? Some words that hit a sympathetic resonance with your perception of the world, yet may not be scientifically accurate? Some words that convey the gist of it without the details?
I've given some suggestions - you've not said why they don't explain it to you. Here's some more:
1) Magnetism is the force between magnets.
2) Magnetism a force that arises from moving charges, which may be caused by using a battery to move a current down a wire, or which may be caused by the tiny electric currents in every atom of some materials coming into alignment so that the tiny magnetic force of each atom aligns.
3) Magnetism does not exist and is a convenient description we assign to the force that arrises when considering the electrostatic interaction of charges moving with respect to one another under special relativity.
4) Magnetism is electrostatics under Lorentz transformations.
Take your pick. Some of them may not be satisfying explanations, but if a dozen words could convey the entire content of electrostatics and special relativity in sufficient detail to be a fully convincing explanation, we wouldn't have invented mathematics
I would have hoped my explanation that magnetism arises from moving electric charges, and that electrons are charges moving around in atoms, and that in iron these little charges can all align making a big, strong field, was a decent middle ground explanation. I guess not.
Post edited at 22:37
1
In reply to wintertree:
Sorry to put you to so much trouble, 3) is the nearest but maybe I'm looking for something that doesn't exist given the way my brain functions. When I push a door open I can "understand" that but only because it seems obvious to the way I think. In reality the true explanation is far more complex as I just consider objects as simple when they aren't really, all more space than matter, but as matter isn't matter either... I can't get my brain round it all any more than what was before the big bang. I'd better just make do with the practical approximations of matter, volts, amps and so on that get me through my daily life and all I can cope with.
Thanks for trying anyway... it reminds me of years ago I couldn't understand entropy either!
Sorry to put you to so much trouble, 3) is the nearest but maybe I'm looking for something that doesn't exist given the way my brain functions. When I push a door open I can "understand" that but only because it seems obvious to the way I think. In reality the true explanation is far more complex as I just consider objects as simple when they aren't really, all more space than matter, but as matter isn't matter either... I can't get my brain round it all any more than what was before the big bang. I'd better just make do with the practical approximations of matter, volts, amps and so on that get me through my daily life and all I can cope with.
Thanks for trying anyway... it reminds me of years ago I couldn't understand entropy either!
In reply to Bruce Hooker:
You do know that when you push a door you never actually get to touch the door, don't you? It is the magnetic forces of the electrons in your finger's atoms repelling the ones in the door's surface...
How's that for a bed thought
You do know that when you push a door you never actually get to touch the door, don't you? It is the magnetic forces of the electrons in your finger's atoms repelling the ones in the door's surface...
How's that for a bed thought
In reply to The Lemming:
Mrs Num Num is a massive great lump, and when she gets into bed the springs and mattress sag nearly to the floorboards and I spiral inwards together with the pillows and biscuit crumbs toward the event horizon she has created.
She's more of a brown hole than a black hole though.
Mrs Num Num is a massive great lump, and when she gets into bed the springs and mattress sag nearly to the floorboards and I spiral inwards together with the pillows and biscuit crumbs toward the event horizon she has created.
She's more of a brown hole than a black hole though.
1
In reply to Bruce Hooker:
But entropy is easy.
> (In reply to wintertree)
>
... it reminds me of years ago I couldn't understand entropy either!>
But entropy is easy.
In reply to Bruce Hooker:
I thought you were a chemical engineer ?
> Thanks for trying anyway... it reminds me of years ago I couldn't understand entropy either!
I thought you were a chemical engineer ?
In reply to Doug:
That explains it then...
> (In reply to Bruce Hooker)
>
> [...]
>
> I thought you were a chemical engineer ?
>
> [...]
>
> I thought you were a chemical engineer ?
That explains it then...
In reply to A Longleat Boulderer:
"We used to think this. They called it the 'Luminiferous Aether', a substance that filled the universe like water in a fish bowl but with several crazy properties. We showed through experimentation that actually this didn't exist. "
So what we now have moved to is a "Particiliferous aether" ? Is spacetime any more than the aether in which light and matter can interact. Matter has been described as congealed light, and as particles can arise and decay back into spacetime then it follows perhaps that matter is a distortion of spacetime, ie a pattern in what could be called the fields of which it may be composed.
this in itself gives an explanation for the limitation on travel to less than the speed of light in a "vacuum", ie the particiliferous aether. Matter travelling is a propagating pattern in spacetime and in so doing is limited to the speed at which patterns can travel through the "vacuum" of spacetime. As speed increases the more the tendency to try to move the fabric of spacetime itself which would require what would appear to be infinite energy. One's apparent mass would become that of the medium itself, ie infinite.
And if matter is pattern in spacetime then gravity follows as the extension of that pattern out into space around the pattern.
"We used to think this. They called it the 'Luminiferous Aether', a substance that filled the universe like water in a fish bowl but with several crazy properties. We showed through experimentation that actually this didn't exist. "
So what we now have moved to is a "Particiliferous aether" ? Is spacetime any more than the aether in which light and matter can interact. Matter has been described as congealed light, and as particles can arise and decay back into spacetime then it follows perhaps that matter is a distortion of spacetime, ie a pattern in what could be called the fields of which it may be composed.
this in itself gives an explanation for the limitation on travel to less than the speed of light in a "vacuum", ie the particiliferous aether. Matter travelling is a propagating pattern in spacetime and in so doing is limited to the speed at which patterns can travel through the "vacuum" of spacetime. As speed increases the more the tendency to try to move the fabric of spacetime itself which would require what would appear to be infinite energy. One's apparent mass would become that of the medium itself, ie infinite.
And if matter is pattern in spacetime then gravity follows as the extension of that pattern out into space around the pattern.
In reply to Doug:
That's why I came across entropy, it popped up in thermodynamic equations but as it doesn't correspond to anything we can touch or feel, like temperature, speed, energy, it always seemed a puzzling notion to me. When a lecturer, in a vain attempt to get though to those of us with a blank look in the back row, explained that it was down to an absence of chaos (or something of the sort) it didn't really improve things! All we could do was go to the common room and have another coffee.
> I thought you were a chemical engineer ?
That's why I came across entropy, it popped up in thermodynamic equations but as it doesn't correspond to anything we can touch or feel, like temperature, speed, energy, it always seemed a puzzling notion to me. When a lecturer, in a vain attempt to get though to those of us with a blank look in the back row, explained that it was down to an absence of chaos (or something of the sort) it didn't really improve things! All we could do was go to the common room and have another coffee.
In reply to Alyson:
But doesn't gravity have an effect on the speed of light? Or is it still going the same speed, but the warping of space-time means it has further to travel?
> The point these 2 clocks illustrate is that the speed of light is the only absolute constant.
But doesn't gravity have an effect on the speed of light? Or is it still going the same speed, but the warping of space-time means it has further to travel?
In reply to julesp:
I think I have lost my paper copy, but it was interesting enough to get another one, probably a kindle version this time. It certainly does seem to clarify a number of previous questions, such as the thought process that was gone through to arrive at modern theory, for example the idea of a fixed, grid-like pattern in the universe relative to which movement could occur or a mysterious fluid called ether that supported waves and why in the end neither of these were either true or useful concepts. They also emphasised the point from Richard Feynman about "if it doesn't agree with experimental results, it is wrong" and "if a theory can't be disproved, it is no use" (which is not quite the same as saying it is wrong, but precious close).
Like I say, some of the commentaries were quite sniffy about it, maybe justifiably so but it seems worth persisting with, even if heavy going on occasion.
> Thanks Simon will give it a try
I think I have lost my paper copy, but it was interesting enough to get another one, probably a kindle version this time. It certainly does seem to clarify a number of previous questions, such as the thought process that was gone through to arrive at modern theory, for example the idea of a fixed, grid-like pattern in the universe relative to which movement could occur or a mysterious fluid called ether that supported waves and why in the end neither of these were either true or useful concepts. They also emphasised the point from Richard Feynman about "if it doesn't agree with experimental results, it is wrong" and "if a theory can't be disproved, it is no use" (which is not quite the same as saying it is wrong, but precious close).
Like I say, some of the commentaries were quite sniffy about it, maybe justifiably so but it seems worth persisting with, even if heavy going on occasion.
In reply to Removed UserBwox:
The speed of light in a vacuum is believed to be a constant. However this refers to travelling through space, so if space is non standard or dynamic then the time taken to travel changes. Hence the discovery of galaxies that have a recessional velocity that can reach or exceed the speed of light relative to our position in the universe. Not because the speed of light is exceeded but because, in theory, space is expanding.
The speed of light in a vacuum is believed to be a constant. However this refers to travelling through space, so if space is non standard or dynamic then the time taken to travel changes. Hence the discovery of galaxies that have a recessional velocity that can reach or exceed the speed of light relative to our position in the universe. Not because the speed of light is exceeded but because, in theory, space is expanding.
In reply to Bruce Hooker:
Of course it's rotation, not the rotation on it's axis for day/night cycle, but the yearly 67,108 mph slingshot round the sun, which produces the 1 G of earths gravitational pull which we feel on the surface. Every day situations will produce this effect like driving fast around a corner in your car.
Or if you want to see it as curvature of space/time or maybe you could move on to equations such as inverted space/time, which would be the concept of time/space or under it's more common name of time travel, or even black project research into Einstein-Rosen bridges, that would be an interesting subject, but you may need to do a little basic reading on simple subjects like entropy first if you want to contribute any relevant ideas ;+)
> I think JS was joking about Earth having gravity because it is spinning, that's not the case, in fact it spinning reduces our perception of gravity on the surface. Things have gravity between them, ie. are attracted to each other, because of their mass... which doesn't answer your question, and which puzzles me too. Reading this thread it seems clear that no one posting here knows the answer really and as there are several probably no one can answer your question in simple terms... all the talk of space time etc isn't answering it's just moving goal posts.
Of course it's rotation, not the rotation on it's axis for day/night cycle, but the yearly 67,108 mph slingshot round the sun, which produces the 1 G of earths gravitational pull which we feel on the surface. Every day situations will produce this effect like driving fast around a corner in your car.
Or if you want to see it as curvature of space/time or maybe you could move on to equations such as inverted space/time, which would be the concept of time/space or under it's more common name of time travel, or even black project research into Einstein-Rosen bridges, that would be an interesting subject, but you may need to do a little basic reading on simple subjects like entropy first if you want to contribute any relevant ideas ;+)
Post edited at 19:36
In reply to John Simpson:
Don't be cruel, some may think you are being serious, not many perhaps but some, the ones who think the yanks never really reached the moon or blew up the Trade Centre themselves. It's naughty to encourage them.
Don't be cruel, some may think you are being serious, not many perhaps but some, the ones who think the yanks never really reached the moon or blew up the Trade Centre themselves. It's naughty to encourage them.
In reply to Bruce Hooker:
Well I'm sure you know how it is, and if we're going down the garden path, the Yanks never really reached the moon, it was the Germans who put the bones of it together and the Yanks just put a first class test pilot behind the controls. And then the Yanks needed some help on that downtown redevelopment demolition job, and this time so they say they used their other friends the Jews.
It's a funny old world!
Well I'm sure you know how it is, and if we're going down the garden path, the Yanks never really reached the moon, it was the Germans who put the bones of it together and the Yanks just put a first class test pilot behind the controls. And then the Yanks needed some help on that downtown redevelopment demolition job, and this time so they say they used their other friends the Jews.
It's a funny old world!
1
In reply to The Lemming:
And Gravity is missing in parts of Canada
http://science.howstuffworks.com/environmental/earth/geophysics/missing-gra...
And Gravity is missing in parts of Canada
http://science.howstuffworks.com/environmental/earth/geophysics/missing-gra...
In reply to The Lemming:
The simplest answer to your question...
Mass.
Cheers
LD
The simplest answer to your question...
> What makes stuff pull towards bigger stuff?
Mass.
Cheers
LD
In reply to SiGregory:
I don't think you can after an 'initial window' where you can edit/delete.
> (In reply to SiGregory)
>
> How do I delete a post after I realise I was being a dick?
>
> How do I delete a post after I realise I was being a dick?
I don't think you can after an 'initial window' where you can edit/delete.
1
In reply to John Simpson:
As Wolfgang Pauli would say, this is "Not even wrong."
In the event that you're actually serious, it's probably worth pointing out why. The force exerted by one body on another due to gravity is given by
Fg = m1 * m2 * G / d^2
where m1 and m2 are the masses of the bodies involved, d is the distance between their respective centres of mass and G is the Gravitational Constant ( 6.67 * 10^-11 or thereabouts ). So the force exerted by the Earth on 1kg of mass on the surface is given by
Fg = 5.97 * 10^24 * 6.67 * 10^-11 / (6371000)^2
= 9.81 = 1g
If you can point out where in this equation the angular velocity of the Earth around the Sun factors in ( a complicated expression in itself as the Sun is also rotating around the centre of the Milky Way, and so on ad infinitum ), then I will consider myself corrected.
> Of course it's rotation, not the rotation on it's axis for day/night cycle, but the yearly 67,108 mph slingshot round the sun, which produces the 1 G of earths gravitational pull which we feel on the surface.
As Wolfgang Pauli would say, this is "Not even wrong."
In the event that you're actually serious, it's probably worth pointing out why. The force exerted by one body on another due to gravity is given by
Fg = m1 * m2 * G / d^2
where m1 and m2 are the masses of the bodies involved, d is the distance between their respective centres of mass and G is the Gravitational Constant ( 6.67 * 10^-11 or thereabouts ). So the force exerted by the Earth on 1kg of mass on the surface is given by
Fg = 5.97 * 10^24 * 6.67 * 10^-11 / (6371000)^2
= 9.81 = 1g
If you can point out where in this equation the angular velocity of the Earth around the Sun factors in ( a complicated expression in itself as the Sun is also rotating around the centre of the Milky Way, and so on ad infinitum ), then I will consider myself corrected.
Post edited at 16:19
In reply to The Lemming:
Anyone have the mental image of Arnold Schwarzenegger letting Sully go in Commando ?
Lol
Anyone have the mental image of Arnold Schwarzenegger letting Sully go in Commando ?
Lol
In reply to planetmarshall:
You'll never find it in that equation because that equation calculates acceleration due to gravity and give a value for a celestial body or similar. It doesn't provide the theory or equations of why the gravity exists, this is currently not known in none-classified mainstream physics. Of course I could pretend I made this theory up, but I didn't I read about it on an military forum, in a discussion about the work been done into anti gravity drives, so if you have any more questions maybe you could send an email to Area 51, I'm sure they'll be pleased to help ;+)
You'll never find it in that equation because that equation calculates acceleration due to gravity and give a value for a celestial body or similar. It doesn't provide the theory or equations of why the gravity exists, this is currently not known in none-classified mainstream physics. Of course I could pretend I made this theory up, but I didn't I read about it on an military forum, in a discussion about the work been done into anti gravity drives, so if you have any more questions maybe you could send an email to Area 51, I'm sure they'll be pleased to help ;+)
In reply to planetmarshall:
Oh, it's better than that. If John Simpson's theory were true the force would be toward the earth during the day and away from it at night. Day-time climbing would be very risky but climbing in the dark would be really easy.
Oh, it's better than that. If John Simpson's theory were true the force would be toward the earth during the day and away from it at night. Day-time climbing would be very risky but climbing in the dark would be really easy.
In reply to csambrook:
I wonder if this is how Newton plagiarized himself into the history books as a scientific legend, by taking other people lifetime works and renaming it as his own? But just in case you missed it, as I said before, it's not my theory!
> Oh, it's better than that. If John Simpson's theory were true the force would be toward the earth during the day and away from it at night. Day-time climbing would be very risky but climbing in the dark would be really easy.
I wonder if this is how Newton plagiarized himself into the history books as a scientific legend, by taking other people lifetime works and renaming it as his own? But just in case you missed it, as I said before, it's not my theory!
Post edited at 23:05
In reply to John Simpson:
Newton got into the history books by originating, developing or contributing to several theories in mathematics and the natural sciences that actually worked, despite being a prize arsehole. I'm not aware of anything that he directly plagiarised, unless you're referring to his well documented spat with Leibniz.
>But just in case you missed it, as I said before, it's not my theory!
Just as well, since it's demonstrably nonsense, and not even imaginative enough to be cranky. (see http://www.crank.net for some truly batshit craziness ).
> I wonder if this is how Newton plagiarized himself into the history books as a scientific legend, by taking other people lifetime works and renaming it as his own?
Newton got into the history books by originating, developing or contributing to several theories in mathematics and the natural sciences that actually worked, despite being a prize arsehole. I'm not aware of anything that he directly plagiarised, unless you're referring to his well documented spat with Leibniz.
>But just in case you missed it, as I said before, it's not my theory!
Just as well, since it's demonstrably nonsense, and not even imaginative enough to be cranky. (see http://www.crank.net for some truly batshit craziness ).
In reply to John Simpson:
It seems entirely sensible, in matters of astrophysics, to defer to the wisdom of someone called 'planetmarshall'
> You'll never find it in that equation because that equation calculates acceleration due to gravity and give a value for a celestial body or similar. It doesn't provide the theory or equations of why the gravity exists, this is currently not known in none-classified mainstream physics.
It seems entirely sensible, in matters of astrophysics, to defer to the wisdom of someone called 'planetmarshall'
In reply to Alyson:
I happily delude myself with the thought I may live until my 90's, which means at 34 I'm only really a third of the way into my life more or less, and suddenly things seem brighter. It might be true.
> Gravity is so interesting because all other physical forces (I think!! recalling A level physics from a dismayingly large number of years ago)
I happily delude myself with the thought I may live until my 90's, which means at 34 I'm only really a third of the way into my life more or less, and suddenly things seem brighter. It might be true.
Post edited at 14:41
In reply to planetmarshall:
Well the well documented spat, all this time later is effectively going to be the greatest hit, neither of us really know what went on, his interest in the dark arts of alchemy is a sign that the full story has much more depth.
Well it's quite easy to demonstrate g force through rotation as if it wasn't roller coasters wouldn't exist. The theory of gravity and mass is much harder to demonstrate in a real world situation, As for a start you've got to stop the whole universe moving.
And I'll leave you to your crank site, I don't really see any point in reading them.
> Newton got into the history books by originating, developing or contributing to several theories in mathematics and the natural sciences that actually worked, despite being a prize arsehole. I'm not aware of anything that he directly plagiarised, unless you're referring to his well documented spat with Leibniz.
Well the well documented spat, all this time later is effectively going to be the greatest hit, neither of us really know what went on, his interest in the dark arts of alchemy is a sign that the full story has much more depth.
> >But just in case you missed it, as I said before, it's not my theory!
> Just as well, since it's demonstrably nonsense, and not even imaginative enough to be cranky. (see http://www.crank.net for some truly batshit craziness ).
Well it's quite easy to demonstrate g force through rotation as if it wasn't roller coasters wouldn't exist. The theory of gravity and mass is much harder to demonstrate in a real world situation, As for a start you've got to stop the whole universe moving.
And I'll leave you to your crank site, I don't really see any point in reading them.
In reply to nufkin:
Maybe this wisdom will come later, fingers crossed eh! x
> It seems entirely sensible, in matters of astrophysics, to defer to the wisdom of someone called 'planetmarshall'
Maybe this wisdom will come later, fingers crossed eh! x
In reply to John Simpson:
Just not with you at all here. Acceleration due to gravity is dependent on only the masses of the objects involved and the distance between them. No other variables are involved - and certainly not angular velocity. Are you seriously disputing this? Then how do you explain that this simple formula predicts the motion of the planets, the orbits of satellites and the rate at which objects fall to the ground? Coincidence?
Just not with you at all here. Acceleration due to gravity is dependent on only the masses of the objects involved and the distance between them. No other variables are involved - and certainly not angular velocity. Are you seriously disputing this? Then how do you explain that this simple formula predicts the motion of the planets, the orbits of satellites and the rate at which objects fall to the ground? Coincidence?
In reply to planetmarshall:
Acceleration due to gravity defines gravitational pull of said object it doesn't define why the object pulls, so it's not that I can dispute a theory because the theory doesn't exist, acceleration due to gravity is a calculation of the results of the force of gravity which isn't fully understood, as far as i can gather this is what the standard model is working towards.
The formula you speak of models the actions of the bodies under study.
So to take this forward, if you produce a theory which ignores, the vast turning forces of heavenly bodies it's probably not going to define the full picture.
> Just not with you at all here. Acceleration due to gravity is dependent on only the masses of the objects involved and the distance between them. No other variables are involved - and certainly not angular velocity. Are you seriously disputing this? Then how do you explain that this simple formula predicts the motion of the planets, the orbits of satellites and the rate at which objects fall to the ground? Coincidence?
Acceleration due to gravity defines gravitational pull of said object it doesn't define why the object pulls, so it's not that I can dispute a theory because the theory doesn't exist, acceleration due to gravity is a calculation of the results of the force of gravity which isn't fully understood, as far as i can gather this is what the standard model is working towards.
The formula you speak of models the actions of the bodies under study.
So to take this forward, if you produce a theory which ignores, the vast turning forces of heavenly bodies it's probably not going to define the full picture.
In reply to planetmarshall:
ps, i'm going out now, so won't reply till tomorrow. I only have Bsc in mechanical science, so not an astro physicist, however everything I was taught by mainstream academia, said we don't understand the full mechanics of gravity and unless something has changed I assume that is the same, hence why this whole rotational theory seems to me to have to play a part.
Coel you out there?
ps, i'm going out now, so won't reply till tomorrow. I only have Bsc in mechanical science, so not an astro physicist, however everything I was taught by mainstream academia, said we don't understand the full mechanics of gravity and unless something has changed I assume that is the same, hence why this whole rotational theory seems to me to have to play a part.
Coel you out there?
In reply to The Lemming:
Gravity is spectacularly well understood at all length scales from 10^(-17) to 10^(19) meters! And it may well be valid down to much smaller distances. I think the usual quantum vs. gravity 'problem' is often overstated- we've got a quantum theory of gravity that's perfectly sensible. The only issue is that the theory itself tells us that at very very small length scales (much smaller than above!) there has to be something new, which at not such tiny scales simplifies to the theory we've got. What exactly this new theory is is hard to pin down because it happens at such small scales that there's no hope of doing direct experiments and you have to hope it feeds down into other things so we can observe it indirectly.
More generally, there's no reason to think the underlying theory of gravity etc. will have a explanation that kindof 'makes sense' to us intuitively. We're evolved to have a gut feeling for, and spend our lives surrounded by, stuff that's about the same size as us. But the universe at small scales behaves nothing like everyday stuff.
Gravity is spectacularly well understood at all length scales from 10^(-17) to 10^(19) meters! And it may well be valid down to much smaller distances. I think the usual quantum vs. gravity 'problem' is often overstated- we've got a quantum theory of gravity that's perfectly sensible. The only issue is that the theory itself tells us that at very very small length scales (much smaller than above!) there has to be something new, which at not such tiny scales simplifies to the theory we've got. What exactly this new theory is is hard to pin down because it happens at such small scales that there's no hope of doing direct experiments and you have to hope it feeds down into other things so we can observe it indirectly.
More generally, there's no reason to think the underlying theory of gravity etc. will have a explanation that kindof 'makes sense' to us intuitively. We're evolved to have a gut feeling for, and spend our lives surrounded by, stuff that's about the same size as us. But the universe at small scales behaves nothing like everyday stuff.
In reply to The Lemming:
Prof Cox is explaining it on BBC 2 right now (in a dumbed down populist sort of way)
Prof Cox is explaining it on BBC 2 right now (in a dumbed down populist sort of way)
In reply to kevin stephens:
My brain hurts.
I have just come on here to ask about what he just said and you beat me to it.
So, is gravity an illusion?
Something to do with the theory of relativity and gravity being an illusion. Can it be that what we are witnessing, we call gravity but is actually a normal process in the universe but not actually gravity?
brain hurts.
> Prof Cox is explaining it on BBC 2 right now (in a dumbed down populist sort of way)
My brain hurts.
I have just come on here to ask about what he just said and you beat me to it.
So, is gravity an illusion?
Something to do with the theory of relativity and gravity being an illusion. Can it be that what we are witnessing, we call gravity but is actually a normal process in the universe but not actually gravity?
brain hurts.
In reply to The Lemming:
Depends on what's meant by illusion. Einstein theorised that gravity is an effect of the curvature of space, brought about by massive objects, rather than a force as such ( think about a marble placed in the centre of a cloth. It warps the cloth causing other objects on the cloth to move toward it ).
Among other things, the theory explains the orbit of mercury, gravitational lensing and allows GPS to work accurately (the deflection of GPS signals due to curvature of spacetime around the earth has to be accounted for). So if anything supercedes it, it would have to explain all these things and more.
> Something to do with the theory of relativity and gravity being an illusion. Can it be that what we are witnessing, we call gravity but is actually a normal process in the universe but not actually gravity?
Depends on what's meant by illusion. Einstein theorised that gravity is an effect of the curvature of space, brought about by massive objects, rather than a force as such ( think about a marble placed in the centre of a cloth. It warps the cloth causing other objects on the cloth to move toward it ).
Among other things, the theory explains the orbit of mercury, gravitational lensing and allows GPS to work accurately (the deflection of GPS signals due to curvature of spacetime around the earth has to be accounted for). So if anything supercedes it, it would have to explain all these things and more.
In reply to planetmarshall:
Up until a few hundred years ago we thought that everything revolved around the Earth because that is what we observed and until our understanding improved, this was logical.
Could something similar be happening with us observing stuff falling because that is how we observe them with our current way of thinking?
And we call this observation, gravity.
Last night on the 'Human Universe' an experiment was performed in a huge vacuum chamber where a bowling ball and feathers were dropped from a great heigh. When the objects were dropped in a room full of air then the bowling ball smashed it to the ground first while the feathers lightly fluttered down.
The second experiment was performed in a room with all the air removed. This time the ball and feathers fell to the ground at the exact same time. Coxy rightly explained that there was no air resistance involved but rather than saying that gravity caused both objects to fall at the same time, he said that the objects were not falling at all when you considered Einstein's theory of relativity.
Way, way over my head.
Could our concept of 'gravity' be as flawed as first thinking that the universe revolved around the Earth, until our understanding changes this?
Could it be hard to explain why gravity works because gravity does not exist in the way that we observe it today?
> Depends on what's meant by illusion.
Up until a few hundred years ago we thought that everything revolved around the Earth because that is what we observed and until our understanding improved, this was logical.
Could something similar be happening with us observing stuff falling because that is how we observe them with our current way of thinking?
And we call this observation, gravity.
Last night on the 'Human Universe' an experiment was performed in a huge vacuum chamber where a bowling ball and feathers were dropped from a great heigh. When the objects were dropped in a room full of air then the bowling ball smashed it to the ground first while the feathers lightly fluttered down.
The second experiment was performed in a room with all the air removed. This time the ball and feathers fell to the ground at the exact same time. Coxy rightly explained that there was no air resistance involved but rather than saying that gravity caused both objects to fall at the same time, he said that the objects were not falling at all when you considered Einstein's theory of relativity.
Way, way over my head.
Could our concept of 'gravity' be as flawed as first thinking that the universe revolved around the Earth, until our understanding changes this?
Could it be hard to explain why gravity works because gravity does not exist in the way that we observe it today?
In reply to The Lemming:
No
No
> Could our concept of 'gravity' be as flawed as first thinking that the universe revolved around the Earth, until our understanding changes this?
No
> Could it be hard to explain why gravity works because gravity does not exist in the way that we observe it today?
No
In reply to John Simpson:
"g force" applied to roller coasters is not the same as gravitational force. All it does is quantify a different force (centripetal force in this case) in a unit that makes its effect easy to compare to gravitational force.
"g force" applied to roller coasters is not the same as gravitational force. All it does is quantify a different force (centripetal force in this case) in a unit that makes its effect easy to compare to gravitational force.
In reply to The Lemming:
Just so you know, that's total bollox. Over 2,000 years ago ancient scholars had observed that the sun was much bigger than the earth and that it was therefore likely that the earth moved around the sun. Please don't mistake the delusions of a couple of churches for global history.
Unlikely. We know that we do not know everything about how gravity works, but there are plenty of things we know a lot more about that are still hard to explain to someone without the relevant knowledge and training. This is because Stuff is not inherently simple. Perhaps one day someone will find a theory that explains everything that is so simple that everyone understands it after 5 minutes of watching a TV personality, but it seems unlikely.
> up until a few hundred years ago we thought that everything revolved around the Earth because that is what we observed and until our understanding improved, this was logical.
Just so you know, that's total bollox. Over 2,000 years ago ancient scholars had observed that the sun was much bigger than the earth and that it was therefore likely that the earth moved around the sun. Please don't mistake the delusions of a couple of churches for global history.
> Could it be hard to explain why gravity works because gravity does not exist in the way that we observe it today?
Unlikely. We know that we do not know everything about how gravity works, but there are plenty of things we know a lot more about that are still hard to explain to someone without the relevant knowledge and training. This is because Stuff is not inherently simple. Perhaps one day someone will find a theory that explains everything that is so simple that everyone understands it after 5 minutes of watching a TV personality, but it seems unlikely.
Post edited at 12:10
In reply to wintertree:
Feel free to patronise me some more.
Or, as others are trying, you could help broaden my understanding on such a subject?
> Perhaps one day someone will find a theory that explains everything that is so simple that everyone understands it after 5 minutes of watching a TV personality, but it seems unlikely.
Feel free to patronise me some more.
Or, as others are trying, you could help broaden my understanding on such a subject?
In reply to The Lemming:
I wasn't patronising you. I was seeking to improve your understanding of the history of heliocentricity as it seemed quite lacking, indeed arrogant or just plain wrong spring to mind.
You've not commented on my posts seeking to convey actual insight and understanding.
Or is it patronisng to say that something is really hard?
> Feel free to patronise me some more.
> Or, as others are trying, you could help broaden my understanding on such a subject?
I wasn't patronising you. I was seeking to improve your understanding of the history of heliocentricity as it seemed quite lacking, indeed arrogant or just plain wrong spring to mind.
You've not commented on my posts seeking to convey actual insight and understanding.
Or is it patronisng to say that something is really hard?
Post edited at 13:25
In reply to wintertree:
My apologies.
I keep going over this thread and more and more questions keep popping up, the most curious of which was the experiment of the ball and feathers and the statement that the objects are not falling.
Brain really hurts, especially as I can see them falling.
> I wasn't patronising you.
My apologies.
I keep going over this thread and more and more questions keep popping up, the most curious of which was the experiment of the ball and feathers and the statement that the objects are not falling.
Brain really hurts, especially as I can see them falling.
In reply to The Lemming:
The problem is separating "explanations" (how stuff works) from "interpretations" (concrete analogies drawn from theory).
Clearly they fall. In the primary interpretation of GR they move in a higher dimensional space in other ways. Cox et all tend to take that interpretation - meant to help understand a theory - and muddle it as an explanation of what we see.
In reality I think the whole bent space things is an interpretation and that we don't yet know for sure whats really going on.
The problem is separating "explanations" (how stuff works) from "interpretations" (concrete analogies drawn from theory).
Clearly they fall. In the primary interpretation of GR they move in a higher dimensional space in other ways. Cox et all tend to take that interpretation - meant to help understand a theory - and muddle it as an explanation of what we see.
In reality I think the whole bent space things is an interpretation and that we don't yet know for sure whats really going on.
This topic has been archived, and won't accept reply postings.
Loading Notifications...