# What if spacetime were a kind of fluid? **URL:** \ **Category:** Great Debates\ **Created:** [April 23, 2014, 2:59pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772 "2014-04-23T14:59:01Z")\ **Posts on this page:** 20\ **Page:** 15
**Author:** ![Jonathan\_Chance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jonathan_chance/32/701_2.png) [@Jonathan\_Chance](https://boards.straightdope.com/u/Jonathan_Chance)\ **Post date:** [April 30, 2014, 10:19pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/281 "2014-04-30T22:19:06Z")
Both of you, drop it. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [April 30, 2014, 10:46pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/282 "2014-04-30T22:46:05Z")
> [@mpc755](#): > > . . . As you push the bowling ball in order to accelerate it and the supersolid offers up resistance to that push the bowling ball is condensed somewhat. . . . > > . . . the bowling ball rolls on forever through the supersolid. Contradictory. If there were resistance, that would slow the ball, so that, over time, it would drift to a stop. If it rolls on forever, then there could be no resistance. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [April 30, 2014, 10:50pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/283 "2014-04-30T22:50:37Z")
> [@Trinopus](#): > > Contradictory. If there were resistance, that would slow the ball, so that, over time, it would drift to a stop. If it rolls on forever, then there could be no resistance. A boat has a bow wave. A surfer rides the ocean wave. As the bowling ball moves through the supersolid it displaces the supersolid. This is the boat has a bow wave part. As the supersolid fills-in where the bowling ball was it displaces the bowling ball. This is the surfer rides the ocean wave part. Both occur simultaneously with equal force and the bowling ball rolls on forever through the supersolid. ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [May 1, 2014, 2:05am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/284 "2014-05-01T02:05:22Z")
> [@mpc755](#): > > As the bowling ball moves through the supersolid it displaces the supersolid. This is the boat has a bow wave part. > > As the supersolid fills-in where the bowling ball was it displaces the bowling ball. This is the surfer rides the ocean wave part. > > Both occur simultaneously with equal force and the bowling ball rolls on forever through the supersolid. Actual Object moves through Hypothetical Object, displacing Hypothetical Object. This is the Other Actual Object has an Other, Other Actual Object part. As the Hypothetical Object fills in where the Actual Object was it displaces the Actual Object. Both occur simultaneously with equal force and the Actual Object rolls on forever through the Hypothetical Object. I can`t imagine why the analogies you craft make no sense. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 2:18am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/285 "2014-05-01T02:18:20Z")
> [@Grey](#): > > Actual Object moves through Hypothetical Object, displacing Hypothetical Object. This is the Other Actual Object has an Other, Other Actual Object part. > > As the Hypothetical Object fills in where the Actual Object was it displaces the Actual Object. > > Both occur simultaneously with equal force and the Actual Object rolls on forever through the Hypothetical Object. > > I can`t imagine why the analogies you craft make no sense. In the following video the particle generates its own wave which pushes it along and guides it. ‘The pilot-wave dynamics of walking droplets’ [![](https://img.youtube.com/vi/nmC0ygr08tE/hqdefault.jpg "The pilot-wave dynamics of walking droplets") ](https://www.youtube.com/watch?v=nmC0ygr08tE) ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [May 1, 2014, 2:20am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/286 "2014-05-01T02:20:43Z")
> [@Jonathan\_Chance](#): > > Both of you, drop it. You’re right, that was uncalled for. **mpc755** , sorry about that, I was out of line. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 2:23am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/287 "2014-05-01T02:23:40Z")
> [@Telemark](#): > > You’re right, that was uncalled for. > > **mpc755** , sorry about that, I was out of line. np ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [May 1, 2014, 4:52am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/288 "2014-05-01T04:52:55Z")
> [@mpc755](#): > > The next time you add value to this debate will be the first time you add value to this debate. > [@mpc755](#): > > Thanks for _not_ adding any value to the ‘conversation’. Knock it off. Your persistently snide remarks are doing nothing to encourage us to allow you to continue to post. Telemark, do not respond to snide posts in kind. [/Moderating] ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [May 1, 2014, 5:30am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/289 "2014-05-01T05:30:46Z")
> [@mpc755](#): > > A boat has a bow wave. > A surfer rides the ocean wave. > > As the bowling ball moves through the supersolid it displaces the supersolid. This is the boat has a bow wave part. > > As the supersolid fills-in where the bowling ball was it displaces the bowling ball. This is the surfer rides the ocean wave part. > > Both occur simultaneously with equal force and the bowling ball rolls on forever through the supersolid. You can have surface waves only if you have a surface. You have said that the aether is not compressible. Are you now proposing that there is a surface, a boundary, below which there is aether and above which there isn’t? You can’t have a surface wave underwater, unless you permit compressibility. You continue to promote self-contradictory explanations. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [May 1, 2014, 9:08am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/290 "2014-05-01T09:08:54Z")
> [@mpc755](#): > > What you are saying is that since we can not know the position and momentum of the particle without detecting it then any theory which refers to our inability to determine the position and momentum of the particle is a hidden variable theory. Like myself, I presume he’s saying that because that’s how hidden variable theories are defined, and it aids communication to use words and concepts in the way they are generally understood rather than making up new meanings and then refusing to even clarify them. > [@](#): > > You are saying hidden variable theories are refuted by Bell’s Inequality. Therefore, any theory where the position and momentum of the pair can not be known without detection and where the pair are not physically or superluminally connected is refuted. Again, that’s just the way the facts are: if your theory has 1) definite position and momentum at all times, and 2) no nonlocal influences, then it is refuted by experiment, whether you want to call it a ‘hidden variable theory’ or not. If an ‘exposed variable theory’ is one in which position and momentum are always definite, and there are no nonlocal influences, then it is experimentally refuted. > [@](#): > > I am saying the whole notion of hidden variables was an early attempt to describe entanglement. This is true, but of course, it’s not in contradiction with what any of us say. > [@](#): > > I am saying there are more than two possible explanations. In an exposed variable theory the position and momentum of each of the pair of downconverted photons is knowable to the other as, due to conservation of momentum, the photons are propagating with opposite angular momentums. But then, you have a theory in which the total system momentum _p_ is definite, the momentum _p[sub]1[/sub]_ of photon 1 is definite, and from this, it follows that the momentum _p - p[sub]1[/sub]_ of the photon 2 is likewise definite. Is that, or is that not the case in your ‘exposed variable theory’? > [@](#): > > I am stating all theories where the position and momentum can not be known to us are not all hidden variable theories. The information about the outcome of all possible measurements is not already present in both particles. So, the outcome to what measurements are not already present? If I were to make a measurement of momentum on either of the photons, would the outcome be predetermined, i.e. such that making the same measurement would necessarily yield the same outcome? If I were to make a position measurements, woule that outcome be predetermined? > [@](#): > > What is known to each of the pair is a specific position and momentum of the pair at any particular instant. So the measurement outcomes of these quantities is predetermined, right? > [@](#): > > de Broglie’s wave mechanics and double solution theory is not a hidden variable theory. It is an exposed variable theory as the pair are created with opposite angular momentums, have a physical wave which guides them, are not physically or superluminally connected and are able to determine the position and momentum of each other. Is the value of the angular momentum determined, or is just the fact that the angular momentum is oppositely aligned to one another determined? > [@mpc755](#): > > The third quote is stating the wave function wave is of statistical nature only and it does not physically determine the path the particle travels. The associated physical wave guides the particle. The third quote says nothing about the statistical nature of the wave function, and it says nothing guiding particles; I’m wondering whether we’re reading the same quote, in fact. In any case, that the wave function is statistical and does not determine the motion of the particle is exactly what I said; and the physical wave guides the particle by means of the guiding equation, which determines the motion of the particle based on the quantum potential. And still, any and all answers to the following questions would be greatly appreciated; in fact, if you continue to fail to show me the courtesy of providing the very simple clarifications I’ve asked for, then I don’t think I can even pretend you’re carrying on this conversation in good faith, and are interested in anything but stuffing your misunderstandings and misrepresentations into others’ faces and getting insulting in lieu of supporting and arguing for your views. [ol] [li]In your theory, does each particle always have a definite position x = (some value) and a definite momentum p = (some value)?[/li][li]In your theory, does the position and/or momentum of one particle depend instantaneously on that of any other?[/li][li]Do you believe that in de Broglie’s double solution theory, every particle always has a definite position/momentum?[/li][li]Do you believe that in de Broglie’s souble solution theory, the position/momentum of a particle can be instantaneously influenced (via the nonlocal quantum potential) by those of other particles?[/li][li]Do you understand that Bell inequalities apply to every theory in which observable quantities have a definite value even if the quantum state (ψ-wave function) does not determine that value, and there are no nonlocal influences?[/li][li]What is your definition of hidden variables?[/li][li]Do you understand that the definition of ‘hidden variable theory’ (as it is usually used in the literature) is a theory in which there are definite values attributed to observable quantities to which the quantum state does not assign definite values?[/li][li]What is your definition of an ‘exposed variable theory’?[/li][/ol] > [@](#): > > It is now known that dark matter fills ‘empty’ space. Meaning it is the mass which fills ‘empty’ space which swirls. Better described as the state of displacement of the mass which fills ‘empty’ space. Dark matter is considered to be nonbaryonic particles, and is not an element in the frame dragging effect. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 1, 2014, 11:39am UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/291 "2014-05-01T11:39:31Z")
> [@Trinopus](#): > > You can have surface waves only if you have a surface. You have said that the aether is not compressible. Are you now proposing that there is a surface, a boundary, below which there is aether and above which there isn’t? > > You can’t have a surface wave underwater, unless you permit compressibility. > > You continue to promote self-contradictory explanations. This is basically where I got stuck with the idea. There are physics geeks in the thread and there are laymen (like me) - and the OP initially provided discussion points for both, but doesn’t seem to want to engage with the folks who just want the analogy made more lucid. As far as I understand it, the aether being proposed has some property of _having-been-displaced-ness_, which is sort of like pressure, or tension, or something, but is also not like those things. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 1:37pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/292 "2014-05-01T13:37:51Z")
> [@tomndebb](#): > > Knock it off. Your persistently snide remarks are doing nothing to encourage us to allow you to continue to post. > Telemark, do not respond to snide posts in kind. > > [/Moderating] I’m being called dishonest and you say nothing about that. > [@Telemark](#): > > For the people who don’t know physics - it’s clear that you’re being a dishonest debater. You also respond after Telemark and I have settled our differences. > [@](#): > > > [@Telemark](#): > > > > You’re right, that was uncalled for. > > > > **mpc755** , sorry about that, I was out of line. > > > [@mpc755](#): > > > > np ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 1:42pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/293 "2014-05-01T13:42:11Z")
> [@Trinopus](#): > > You can have surface waves only if you have a surface. You have said that the aether is not compressible. Are you now proposing that there is a surface, a boundary, below which there is aether and above which there isn’t? > > You can’t have a surface wave underwater, unless you permit compressibility. > > You continue to promote self-contradictory explanations. It’s an analogy. The same as used by Einstein to describe the ether. ‘Ether and the Theory of Relativity by Albert Einstein’ [http://www-groups.dcs.st-and.ac.uk/~history/Extras/Einstein\_ether.html](http://www-groups.dcs.st-and.ac.uk/~history/Extras/Einstein_ether.html) _“Think of waves on the surface of water. Here we can describe two entirely different things. Either we may observe how the undulatory surface forming the boundary between water and air alters in the course of time; or else-with the help of small floats, for instance - we can observe how the position of the separate particles of water alters in the course of time. If the existence of such floats for tracking the motion of the particles of a fluid were a fundamental impossibility in physics - if, in fact nothing else whatever were observable than the shape of the space occupied by the water as it varies in time, we should have no ground for the assumption that water consists of movable particles. But all the same we could characterise it as a medium.”_ if, in fact nothing else whatever were observable than the shape of the space occupied by the aether as it varies in time, we should have no ground for the assumption that aether consists of movable particles. But all the same we could characterise it as a medium having mass which is displaced by the particles of matter which exist in it and move through it. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 1:47pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/294 "2014-05-01T13:47:12Z")
> [@Half\_Man\_Half\_Wit](#): > > Dark matter is considered to be nonbaryonic particles, and is not an element in the frame dragging effect. And that is where mainstream physics is incorrect. There is no such thing as non-baryonic dark matter anchored to matter. Matter moves through and displaces the mass which fills ‘empty’ space. Frame-dragging is the state of displacement of the mass which fills ‘empty’ space. Aether has mass. _“According to the general theory of relativity space without ether is unthinkable”_ - Albert Einstein The geometrical representation of gravity as curved spacetime physically exists in nature as the state of displacement of the aether. The state of displacement of the aether _is_ gravity. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 1:53pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/295 "2014-05-01T13:53:53Z")
> [@Mangetout](#): > > This is basically where I got stuck with the idea. There are physics geeks in the thread and there are laymen (like me) - and the OP initially provided discussion points for both, but doesn’t seem to want to engage with the folks who just want the analogy made more lucid. > > As far as I understand it, the aether being proposed has some property of _having-been-displaced-ness_, which is sort of like pressure, or tension, or something, but is also not like those things. Watch the following video. As the droplet moves through the silicon it displaces the silicon. As the silicon fills-in where the droplet had been the silicon displaces the droplet. This is the wave back-filling, pushing and guiding the particle. ‘The pilot-wave dynamics of walking droplets’ [![](https://img.youtube.com/vi/nmC0ygr08tE/hqdefault.jpg "The pilot-wave dynamics of walking droplets") ](https://www.youtube.com/watch?v=nmC0ygr08tE) ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [May 1, 2014, 1:59pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/296 "2014-05-01T13:59:36Z")
> [@mpc755](#): > > _“According to the general theory of relativity space without ether is unthinkable”_ - Albert Einstein You didn’t include the entire quote. > [@](#): > > We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an aether. According to the general theory of relativity space without aether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this aether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. **The idea of motion may not be applied to it.** ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 2:11pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/297 "2014-05-01T14:11:01Z")
> [@Telemark](#): > > You didn’t include the entire quote. Every time Einstein refers to motion in terms of the aether it is described as individual particles which can be separately tracked through time. Throughout the article Einstein says the aether does not consist of individual particles which can be separately tracked through time. This is the definition of motion Einstein applies to the aether. _“There may be supposed to be extended physical objects to which the idea of motion cannot be applied. They may not be thought of as consisting of particles which allow themselves to be separately tracked through time.”_ _“as consisting of parts which may be tracked through time”_ This is different than the aether displaced by the particles of matter which exist in it and move through it. Even if we can’t know if the aether consists of individual particles which can be separately tracked through time, or not, does not imply the aether does not have mass and does not imply that it can not be displaced by the particles of matter which exist in it and move through it. ---
**Author:** ![Jonathan\_Chance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jonathan_chance/32/701_2.png) [@Jonathan\_Chance](https://boards.straightdope.com/u/Jonathan_Chance)\ **Post date:** [May 1, 2014, 2:12pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/298 "2014-05-01T14:12:06Z")
> [@mpc755](#): > > _“Think of waves on the surface of water. Here we can describe two entirely different things. Either we may observe how the undulatory surface forming the boundary between water and air alters in the course of time; or else-with the help of small floats, for instance - we can observe how the position of the separate particles of water alters in the course of time. If the existence of such floats for tracking the motion of the particles of a fluid were a fundamental impossibility in physics - if, in fact nothing else whatever were observable than the shape of the space occupied by the water as it varies in time, we should have no ground for the assumption that water consists of movable particles. But all the same we could characterise it as a medium.”_ mpc755, by my count this is the SIXTH time you have posted this quote in the last week _in this thread_. I have told you before that merely repeating yourself is not debating. I have noted it and I’ve given you warnings for it. Yet you continue to repeat the same quotes over and over. This is not debating as it is normally understood. This is another warning and any more can get your posting privileges revoked. Now debate, do not repeat. ---
**Author:** ![mpc755](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mpc755/32/7307_2.png) [@mpc755](https://boards.straightdope.com/u/mpc755)\ **Post date:** [May 1, 2014, 2:25pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/299 "2014-05-01T14:25:00Z")
> [@Jonathan\_Chance](#): > > mpc755, by my count this is the SIXTH time you have posted this quote in the last week _in this thread_. I have told you before that merely repeating yourself is not debating. I have noted it and I’ve given you warnings for it. Yet you continue to repeat the same quotes over and over. > > This is not debating as it is normally understood. This is another warning and any more can get your posting privileges revoked. Now debate, do not repeat. So, what am I to do? After posting this same text five times a poster is stating any analogy having to do with water and surface waves is invalid. How do you expect me to respond to a poster who insists any analogy having to do with water and surface waves is invalid _after_ I have used the Einstein quote five times to demonstrate an analogy using water and surface waves is valid? How am I to respond to the poster when Einstein’s quote _is_ the appropriate response? ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [May 1, 2014, 2:30pm UTC](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772/300 "2014-05-01T14:30:28Z")
> [@mpc755](#): > > _“According to the general theory of relativity space without ether is unthinkable”_ - Albert Einstein. He wrote that way back in 1920, _94 years ago!_ There is no modern aether theory in physics, period. [Previous page](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772.md?page=14) [Next page](https://boards.straightdope.com/t/what-if-spacetime-were-a-kind-of-fluid/686772.md?page=16)