Space-time curvature is incorrect

Discussion in 'Physics & Math' started by Frencheneesz, Aug 26, 2002.

  1. Frencheneesz Amazing Member Registered Senior Member

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    Sorry, i told you my explanation might sound like that, but my idea focuses only on the forces instead of using all but unscientific theories such as entropy, which states that "things tend to get less oraganized". That means almost nothing in science, given that organization is all in opinion.

    I can't exactly say that a philosophy proves much, but i see where you are going. I can see that both of our theories can coexist since neither of us have any observational evidence that one is a better model than the other.

    The thing missing from your acceleration point of view is that both your gravitic captor and yourself would be accelerating towards eachother. Effectively both of you are exerting the same force on eachother, but the more massive galaxy needs much much more force to push than your puny body.

    But i must disagree with you when you say no force is needed. Some force must be responsible for this acceleration. You can't move without a force being acted on you...

    "If we didn't, we couldn't explain how a perfectly spherical star's circumference is less than pi times its diameter. We also couldn't fully explain the precession of mercury's perihelion."
    First of all, how is the diameter of a star derived (PS nothing is perfectly spherical), it is measured from the light emitted from it, right? But then how is the circumference measured? It could be measured using the same light, right?
    Tell me how they got that the circumference was smaller than the diameter. Given that it is impossible to draw a perfect circle with those properties, sounds quite strange to me.

    "For example, if I am accelerating toward the moon thanks to gravity, then why must the moon be under the direct influence of a force of gravity? In other words, why must there be a physical interaction (such as gravitons) between myself and the moon? After all, the Apollo astronauts closed the gap between themselves and the moon just by accelerating towards it."

    Well, I CAN say that there must be a phisical link (direct or indirect) between the moon. In einsteins model, you would be pulled into the moons pit, but in your idea, there must be some sort of force or interaction that makes you accelerate toward the moon FASTER when you get CLOSER to it.

    "So it seems the car is moving the entire universe along my axis of motion."
    So it seems, well not everything is as it seems. In all seriousness, the relativistic frame of reference idea was to explain that you can not have an absolute speed and that if two cars going along the highway at the same speed hit, it would be just as if they hit when they werent moving forward.
    The universe is not connected in any special fasion, If you accelerate in your spaceship by flinging fast moving particles in the other direction, it hardly matters weather there is a universe or not. There is a clear relationship between mass and the amount of work it takes to move that mass. If we were to move all the universe, we would have to do a bunch of pushing, not to mention getting a hold on all the rest of the universe.
    I can give a very easy explanation of how a car can move itself (and i did), but I would like to see you try to explain how a car can move the universe.

    I can see only one more thing that might convince you, gravity is supposed to be projected at the speed of light right? If it is, then your idea cannot be true because it is quite clear that acceleration have instantaneous effects, in other words it does not take 8 minutes for the sun to BE closer to you if you accelerate toward it. You effectively are instantaniously are where you are, period.
    If something were to be moving at faster than the speed of light, You would see it come only after it had arrived, It could touch you (proably taking a chunk of you off at that speed) as a testiment to him being there before you saw his light come rushing in.

    I would be able to explain mercuries perihelion effect, except that it is a completely mathmatical issue, as i see it. How did einstein "correct" for this effect?
    ?
    Frencheneesz
     
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  3. Crisp Gone 4ever Registered Senior Member

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    Hi Frenceneesz,

    "...but my idea focuses only on the forces instead of using all but unscientific theories such as entropy, which states that "things tend to get less oraganized". That means almost nothing in science, given that organization is all in opinion."

    Just for the record I'd like to state that the concept of entropy is alot more than a way of indicating "the amount of organisation" or "disorder". I suggest you grab a good introductory book on thermodynamics before making such claims. But this is not relevant for the discussion, please carry on as you were ...

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    Bye!

    Crisp
     
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  5. zanket Human Valued Senior Member

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    jeffocal

    The discrepancy is the difference between what classical physics says about how far away from Earth the Voyager is expected to be, and where it actually is. The Voyager is closer to Earth by 0.003% of the expected distance. I’m no expert on the subject but I’ve read that the planets do not exhibit the same discrepancy.

    Frencheneesz

    I don’t see what is missing. The Sun accelerates outward in such a way that space comes to it rather than it enlarging itself. (How it manages that is a mystery.) Because the Sun is effectively accelerating towards everything in the universe, it may measurably move closer to a massive galaxy. No pushing or pulling need be involved between the Sun and the galaxy.

    Agreed. When books say “gravity is not a force” I take that to mean that there is no pulling between bodies. But there is still a force within each body that accelerates the surface.

    I won’t be able to explain this properly here. I suggest you get the book Relativity Visualized. Hardly any math in it. You can grasp all the concepts in a few days.

    Einstein’s model is the one I’m describing. There is no pulling in his model. You may read in descriptions of the rubber sheet example that objects “fall” into the pit under the influence of gravity, but that is misleading. In Einstein’s model, when you drop a ball, the ball has no force acting on it. It is not falling per se. The floor effectively comes up to meet the ball. The floor, with you attached, accelerates up, so the ball appears to fall faster and faster. It is only when you hold the ball in your hand or when it meets the floor that a force acts upon it, the force that is accelerating the Earth’s surface.

    I added to my description of Einstein’s model that, in my opinion, if the floor accelerates up in such a way that the Earth does not enlarge itself, then it is just as valid to say that the Earth accelerates space toward itself, in which case no physical link need exist between two bodies, such as gravitons.

    I explain it using your explanation, with the addition that when I remove my foot from the gas pedal and coast, there is no way I can tell whether I’m moving or the universe is. Since I can’t tell, it is just as valid for me to say that I moved the universe during my acceleration as vice versa. Better is to accept that who is moving is irrelevant and instead just focus on relative movement.

    There is no incompatibility. The latest information we have about the Sun is 8 minutes old. When we accelerate toward the Sun, the Sun that we measure ourselves moving closer to is the 8-minute-ago Sun not the Current Sun.
     
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  7. Frencheneesz Amazing Member Registered Senior Member

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    "But there is still a force within each body that accelerates the surface"

    Surface of what?

    "I won’t be able to explain this properly here (Tell me how they got that the circumference was smaller than the diameter)"

    I know that relativity says that space-time is bent in a gravitational field, so the circumference would be normal, but the diameter would be measured along the curve.
    A good picture of this is at http://plus.maths.org/issue18/features/thorne/
    I can understand the concept, but it is beyond me how they could come to the conclusion that the diameter is so long....

    Do you have any evidence that the diameter is so long? measurements?

    "The floor, with you attached, accelerates up, so the ball appears to fall faster and faster. It is only when you hold the ball in your hand or when it meets the floor that a force acts upon it, the force that is accelerating the Earth’s surface."

    Relativity in no way mentions that gravity has direct connections to acceleration, only that you could not tell the difference. The relativistic gravity model doesn't say anything about acceleration as far as i know.
    It is scientific fact that when gravity is in action between a planet and a person, BOTH the planet AND the person are pulled toward a vector point in the center of them that is proportional to the difference in mass.
    Non only that, but there MUST be some sort of interaction between the ball and the planet, otherwise how would the planet know to accelerate toward it in the first place.
    And if the planet accelerates toward the ball, why can't we feel it (if we were standing on the planet)?

    Well, more importantly, what proof is there that this happens? I have proof that an interactive force happens between to objects, i do not have proof of gravitons.

    "Since I can’t tell, it is just as valid for me to say that I moved the universe during my acceleration as vice versa. "

    Im sorry, but i must disagree. There is a direct relationship to how much energy it takes to move an object, and the objects mass. How do you explain the fact that it takes more energy to move a car two feet than it takes to move a pencil two feet?


    Frencheneesz
     
  8. Frencheneesz Amazing Member Registered Senior Member

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    739
    Oh yeah, crisp.

    what are your ideas on this acceleration/gravity stuff?

    I realize that thermodynamics states that all conversions of energy creates loss of energy, but what is "energy". Also, loss of energy can not happen according to the first law of thermodynamics. I know what they MEAN by loss is that it can't be 100% efficient. But Im saying that these laws are very much based on opinion. Obviously the universe doesn't have a specific job for the conversions of energy, so the losses or gains have completely no meaning. How do you proove weather some thing is a loss or a gain, good or bad. It kinda enters the relm of religion...

    oh yeah what are your ideas on this acceleration/gravity stuff?

    Frencheneesz
     
  9. zanket Human Valued Senior Member

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    3,777
    Frencheneesz

    The surface of the body, like the Earth or Sun.

    There are the experimental confirmations of general relativity, such as the observed advance of Mercury’s perihelion, the full explanation of which requires an excess diameter. If you read the (excellent, super simple) book I mentioned, it will make sense. There is nothing magical about the longer diameter; it is a consequence of the constancy of the speed of light, combined with the equivalency of gravity and acceleration. But it takes a good teacher to explain.

    A book I have about the special and general theory, written by Einstein for laymen, has a chapter on how gravity and acceleration are indistinguishable for an observer in a closed box. As I understand it, this equivalence of gravity and acceleration is the cornerstone of the general theory. One site I found says “The Einstein equivalence principle is the heart and soul of gravitational theory.” Conveniently, Einstein’s book is online. Here is the chapter:

    The Equality of Inertial and Gravitational Mass

    It may be a fact that they move toward a vector point. But nothing has proven that they are pulled there. Neither feels a force pulling on them.

    The planet doesn’t have to know about the ball. It just accelerates outward, toward everything outward. Rather than the planet enlarging itself, it brings the space to itself. Anything in that space appears to accelerate toward the planet. The planet is always accelerating.

    You can. Isn’t your butt pressed into your chair right now? That’s because the planet is accelerating your chair against your butt. Or better put (since the planet does not enlarge itself) the planet accelerates the space you reside in against your chair.

    All anybody has done is describe gravity. Nobody has proof of its mechanism, or proof that it is an interactive force. Yet Einstein’s description of gravity explains more of what we observe than yours does (I’m assuming yours is the Newtonian description).

    In my opinion, the main indication that Einstein’s model is more correct is the experimental confirmation of the principle of equivalence, to something like 10 decimal points. Here is some more background:

    What is the difference between the inertial and gravitational mass?

    It would be remarkable if two sources led to the exact same result. Einstein noted (in the chapter linked to above) that if the two cannot be distinguished by any experiment, then they must be considered equivalent. If equivalent, then when you accelerate in your car you are creating a gravitational field that pushes your back against your seat. Or when you sit in your chair, you are accelerating upwards. Either is a valid viewpoint (although the latter is far more intuitive to me).

    Agreed. You raise a good issue, and I was going to take back what I said and agree that when you accelerate in your car, it is valid to say that the car is moving and not the universe. But then in the chapter linked to above I read this: “We have thus good grounds for extending the principle of relativity to include bodies of reference which are accelerated with respect to each other” which means that when you accelerate the car, you can’t tell who is accelerating, you & the universe or the car. But other than giving this reference I can’t better explain it, so you have given me something to think about.

    It seems your point was this: “I don't see any reason that gravity would be involved in this process [acceleration].” And you pointed out that “A car's acceleration is completely derived out of the electromagnetic effect.” But who’s to say that gravity isn’t also derived out of the electromagnetic effect? Especially since no experiment can discern the difference between gravity and acceleration, and because there is a numerically constant relationship between gravity and the electromagnetic force.
     
    Last edited: Aug 29, 2002
  10. Crisp Gone 4ever Registered Senior Member

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    1,339
    Hi Frencheneesz,

    "what are your ideas on this acceleration/gravity stuff?"

    Unfortunately I know too little about General Relativity to talk about it in a sensible manner.

    "I realize that thermodynamics states that all conversions of energy creates loss of energy, but what is "energy". Also, loss of energy can not happen according to the first law of thermodynamics. I know what they MEAN by loss is that it can't be 100% efficient. But Im saying that these laws are very much based on opinion. Obviously the universe doesn't have a specific job for the conversions of energy, so the losses or gains have completely no meaning. How do you proove weather some thing is a loss or a gain, good or bad. It kinda enters the relm of religion... "

    Thermodynamics defines energy using a mathematical relation with entropy. (In fact, there is no uniform definition of energy, it varies between most physical theories). Thermodynamical laws are backed up by calculations (who on their turn are backed up by the three postulates of thermodynamics), so it is not quite based on opinion

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    ... The only thing that can vary is how you define positive energyflow, and this in turn has effects on how the concept of work is defined. Both are mathematically consistent, it is just a matter of definition.

    This ofcourse does not prove anything about "loss" or "gain" (the two terms are dependent on the definition of energyflow). What you refer to as "religious aspect" is in fact the philosophical aspect, in the sense that you can question whether a theory that allows different interpretations of "loss" or "gain" can really describe nature (or our feeling about what a "loss" or "gain" could be). This has been discussed quite a lot before on the forums here (especially in relativity threads

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    ) so I won't go into it deeper here... This message is already off-topic enough

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    Bye!

    Crisp
     
  11. Frencheneesz Amazing Member Registered Senior Member

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    Ok, Zanket,

    I can get the concept of this accelerating outward thing. If something COULD accelerate outward in all directions, then it would make sence, almost. This would mean that there is no gravitational wave or any gravitational force.
    I suppose gravity could be derived from the mechanics of electro-magnetism, although it is completely incomprehensible.

    The only problem is that, the idea breaks the speed of light limit (which i, for one, dont think makes sence). If a body accelerates outward, then eventually it will reach light-speed and beyond. So if you take relativity for truth, this blows it all away.
     
  12. James R Just this guy, you know? Staff Member

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    Apologies if this has already been said, but I'd like to answer Frencheneesz's original question regarding the rubber sheet analogy in general relativity.

    What you have to realise is that the rubber sheet analogy is just that - a story used to try to describe what GR says about gravity in easy-to-understand terms. The analogy, like all good analogies, is useful up to a point, but at some stage you have to get real and look at the actual thing the analogy relates to.

    This particular analogy breaks down when we realise that a force is needed to pull a ball into a pit in the rubber sheet. In GR, the curvature of spacetime <b>is</b> gravity, and there is no "extra" force required. The analogy is ok provided that you accept that objects have a tendency to move towards the low points in the sheet regardless of any "extra" force acting.
     
  13. Prosoothus Registered Senior Member

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    1,973
    James R,

    Frencheneesz has a point. Let's say that your God and you can bend and curve space anyway you see fit. Let's also say that you can compress or expand one or multiple dimensions to get the geometry you desire. There is no reason why an object would move towards your curved, compressed, or uncompressed space rather than just remaining in the same location. Are you claiming that curved space produces some kind of potential difference??

    I can understand how a moving object's path would be influenced by the space curvature, but I don't understand how a stationairy object would be moved by this curvature.

    Tom
     
  14. James R Just this guy, you know? Staff Member

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    Tom,

    <i>There is no reason why an object would move towards your curved, compressed, or uncompressed space rather than just remaining in the same location.</i>

    I could use the same argument to say that there is no reason why any object should ever move rather than staying where it is. Why does a force make something move? Who knows? That question is unanswerable. Why do objects move along geodesics in spacetime? Who knows? They just do. Science tells us how things move, not the ultimate "why".

    <i>Are you claiming that curved space produces some kind of potential difference??</i>

    No. That's a Newtonian idea, actually, which is applicable to gravitational fields (which do not exist in general relativity). On the other hand, there are terms in various GR equations which are vaguely like potential energy terms.

    <i>I can understand how a moving object's path would be influenced by the space curvature, but I don't understand how a stationairy object would be moved by this curvature.</i>

    It's <b>spacetime</b> curvature, not just space curvature.
     
  15. zanket Human Valued Senior Member

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    3,777
    Frencheneesz:

    Very astute. That’s what so great about this forum. In answering your post I realized for the first time how (intuitively) gravitational waves could exist. Before answering your question, I thought they couldn’t. In combination with answering your post and something I read yesterday about the tidal force, it clicked.

    Although objects feel no gravitational forces, they may feel tidal forces where “force” is a misnomer. This “force” is the squeezing and stretching that an object undergoes as it falls into the pit or revolves around a circumference of the pit, to use the rubber sheet example. For example, as the Earth rotates as it revolves around a circumference of the Moon’s pit, the Earth is squeezed perpendicular to the radius of the pit and stretched parallel to the radius. It is squeezed and stretched to match the curved geometry of the pit as it rotates. These tidal forces cause the tides, as Einstein postulated.

    As I understand, Einstein believed in a “fabric” of spacetime. Mass defines the curvature of the fabric. The fabric may ripple to create detectable gravitational waves. The fabric is only a paradigm, a way of looking at things. An equivalent paradigm is that mass defines how space accelerates toward it. But in either paradigm there is spacetime curvature (the pit) that has a curved geometry, and when the mass changes, the geometry of the pit changes, which causes a change in tidal forces that may be detected as gravitational waves.

    In other words, if, for example, two black holes are revolving around each other somewhere in our galaxy, they are continuously varying the geometry of their pit in which the Earth resides. With sufficiently precise equipment, we should be able to detect this as the Earth is alternately (and very slightly) stretched and squeezed.

    Not only to you, but also to every physicist, even as they see a connection! Einstein spent decades on this topic, to no avail.

    The body will never reach light speed, because the speed of light is a limit in the calculus sense, not the highway sense. In a spaceship, you may approach but can never reach the limit. Yet nothing stops you from accelerating as much as you like.

    For example, suppose the accelerator in your ship was a rotating dial. The more you rotate the dial, the higher the velocity (relative to your starting point) that you attain. Suppose 1 rotation brought you to 0.9c, 90% of the speed of light. What speed would you attain if you rotated the dial twice? It would be less than 1c. Even if you rotated the dial at 1000 revolutions per minute for years, you would never reach 1c. Yet if you were moving toward a destination, you would reach that destination faster and faster just like you’d expect. For instance, if you rotated the dial twice, you’d reach your destination twice as fast than if you rotated it only once. To make this happen, rather than you breaching the speed “limit,” space and time flex. This is what Einstein postulated: the speed of light is a constant, but space and time are variable. If you don’t “get” that, then again I recommend a good teacher, such as the author of the book Relativity Visualized.

    So the accelerating-outward planet will never reach light speed. Not in a billion years, not in a billion trillion years. Also note that, unlike the spaceship, the planet is effectively accelerating in all directions (that is, spherically), so it accelerates (brings space to itself) according to the inverse square law. Whereas objects drop next to us at 10 meters per second-squared, the Moon drops toward the Earth at only a few millimeters per second-squared.

    Note as well that Einstein's root model requires that the universe be contracting or expanding. The thinking goes, if all the masses are accelerating towards one another, then what is keeping them apart? Einstein kept them apart by including a "cosmological constant," a made-up value that perfectly counteracts gravity to ensure that the universe does not collapse under the influence of gravity. Later, when it was discovered that the galaxies are expanding away from each other, Einstein called his cosmological constant his "greatest blunder." The expansion removed the need for an arbitrary fix, the cosmological constant. Einstein thought he blundered because he could have postulated--ahead of observations--that the universe must be expanding or contracting.

    Prosoothus:

    I gave an explanation previously in this thread.
     
    Last edited: Sep 1, 2002
  16. Frencheneesz Amazing Member Registered Senior Member

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    739
    "Why does a force make something move?" James R

    Well, a force is defined as something that makes an object move. So Why does something that makes something move make something move? Its the identity property, like in math.

    Science is all about telling the "why" of the universe. What does happen is the first discovery, how it happens is the second giving a law for predictions, and why it happens is the law for the universe.

    My point was that a force DOES need to act on an object to move it, period. Even if we dont know WHY, we do Know how and if gravity is not a force or have a force mechanism, it can't move something, period. This is just like a hand is not a force, but it uses the electromagnetism in the atoms of the skin to repel something it is trying to push.

    "It's spacetime curvature, not just space curvature."

    Sorry if im hypocritical, but i wouldn't try to be so picky. It could get us into a stupid argument.
    Besides this forum is to discuss new ideas, not repeat old ones like einsteins theories and take them for fact. We can take nothing for fact. Everything is wrong except the observations. We need better theories and thats what we are here for, to better Einstein.



    Zanket, I read your post, but um.... I kinda couldn't remeber all that. Could you put your point into a couple sentences?

    One thing I could catch is that the speed of light is constant and spacetime is the variable. I might have already hinted that i don't believe in the theory that light is going the same speed for all frames of refferences. If you are going the speed of light toward the light, relativity says that the light would be going 2 times the speed of light toward you and vice versa. But then it contradicts itself with this constant speed of light crap.

    Seriously, i am interested in trying to put observations into MY theory to prove it wrong. In this way I can better my understanding of phisics. If you don't know what my theory is (maybe i shouldn't call it a theory, more like an idea), then ill explain it, is simple:

    My -Idea- is that the universe works only with particles that produce a force of some sort. Thats it. It takes in no wacky space time curvature stuff or entropy generalizations, unless someone can prove that my theory needs it.

    My current worst enemy is the fact that when you look a couple light-years away, you see things pretty much happening as they were a couple years ago, or so we think. If there was a super-nova, some light would be going faster toward us than other light and therefore arrive earlier. But, the people that observe this say that that does not happen. I have to believe them because I do not have the opbservational experience.

    This would mean that there is an intrincic maximum speed limit of the universe, which is rapidly becoming proven inaccurate.

    More problems sunt: what is light made of, how is it created, and what are photons?

    A lot about light, my theory does not know. But I can explain most other phenomenon, which is good for a theory. The only thing is my theory is in no way a model for how forces work, it just assumes they work and thats that.


    ANYWAY, I can think of another problem with the accelerating outward thing. If all the particles in the earth are acclerating outward, they would be all accelerating with the same rate (if the particles had equivelent mass, which we can assume, since things with more mass are probably just more particles), and that would mean the earth would have as much "acceleration" as a single particle.

    If more than one particle is to create a larger "accleration" there has to be some sort of mechanism to have the accelerations add up. If you have two cars, bumper to bumper, and you accelerate them at the exact same rate, they will not collide. But if one is to help the other accelerate, they must collide or in another way interact.

    But despite all my disproofs, I have something that provides evidence for the connection between gravity and acceleration. If you drop two objects of diferent mass in a vaccum, they fall at the same rate, despite the heavier one having greater gravity.

    This means that the thing that is holding the more massive (greater gravitation force) object back is its momentum, in effect its mass. Its mass makes it have greater pull, but its mass also makes the thing less easy to move. Its QUITE a conincedence that the extra pull COMPLETELY cancels out the momentum resistence of the extra mass.

    This experiment has been taken for fact and is nice support for the idea that gravity and acceleration are directly related.

    Ill stop talking now
     
  17. James R Just this guy, you know? Staff Member

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    Frencheneesz,

    <i>Well, a force is defined as something that makes an object move. So Why does something that makes something move make something move? Its the identity property, like in math.</i>

    According to general relativity, a geodesic is the path that a particle in gravitational free-fall will automatically follow - no force required. So, why does something that makes particles follow it make particles follow it? It's the identity property, like in math.

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    <i>My point was that a force DOES need to act on an object to move it, period.</i>

    How do you reach that conclusion? What about Newton's first law?

    <i>Even if we dont know WHY, we do Know how and if gravity is not a force or have a force mechanism, it can't move something, period.</i>

    Why not?

    I said: "It's spacetime curvature, not just space curvature."

    You said: <i>Sorry if im hypocritical, but i wouldn't try to be so picky. It could get us into a stupid argument.</i>

    It may just be the stupid argument we have to have to get you studied-up on general relativity.

    <i>Besides this forum is to discuss new ideas, not repeat old ones like einsteins theories and take them for fact.</i>

    Oh? I thought this was the "Physics & Math" forum, not the "Free thoughts" forum or the "Pseudoscience" forum.

    <i>We need better theories and thats what we are here for, to better Einstein.</i>

    A worthy aim indeed. Could you please tell me briefly what you think is wrong with Einstein's theories which means they need to be replaced? What experimental observations disagree with Einstein's theories, for example?

    <i>I might have already hinted that i don't believe in the theory that light is going the same speed for all frames of refferences.</i>

    It doesn't matter what you believe. That is what is observed.

    <i>If you are going the speed of light toward the light, relativity says that the light would be going 2 times the speed of light toward you and vice versa.</i>

    Better pull out that relativity text and reread it. That's not what relativity says.

    <i>Seriously, i am interested in trying to put observations into MY theory to prove it wrong.</i>

    Sounds good. That's a scientific approach. Could you please briefly any quantitative predictions your theory makes which differ from the predictions of relativity?

    <i>My -Idea- is that the universe works only with particles that produce a force of some sort. Thats it. It takes in no wacky space time curvature stuff or entropy generalizations, unless someone can prove that my theory needs it.</i>

    Show me some quantitative predictions of your theory and I'll take a look.

    <i>This would mean that there is an intrincic maximum speed limit of the universe, which is rapidly becoming proven inaccurate.</i>

    Really? Who has proven it inaccurate? How?

    <i>More problems sunt: what is light made of, how is it created, and what are photons?</i>

    Standard quantum mechanics has a very good model of light. The term "photon" is entirely a quantum beast.

    <i>But despite all my disproofs, I have something that provides evidence for the connection between gravity and acceleration. If you drop two objects of diferent mass in a vaccum, they fall at the same rate, despite the heavier one having greater gravity.</i>

    That doesn't provide a connection between gravity and acceleration. It provides a connection between inertia and gravitational mass. That particular connection was unexplained until relativity came along; relativity explains it very elegantly.
     
  18. zanket Human Valued Senior Member

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    3,777
    James R:

    Of my small library of relativity books, almost all of them refer to the equality of gravitational and inertial mass interchangeably with the equality of gravity and acceleration. Einstein’s thought experiment (linked to previously in this thread) to show the equality between gravitational and inertial mass is an example of gravity being indiscernible from acceleration. So I fail to see the distinction. Maybe you can enlighten me?

    Frencheneesz:

    OK. This is a side issue and a subtle point, so if you don’t see it and are still interested, hit the books or search online. But here goes: With outward-accelerating masses as a description for gravity, gravitational waves can still exist. Gravitational waves are changing tidal forces. Tidal forces are caused by the fact that, for example, the side of the Earth that is closest to the Moon is accelerating toward the Moon faster than is the opposite side of the Earth (inverse square law). All parts of the Earth are accelerating roughly toward the center of the Moon; that is, towards a point. So the Earth is squeezed into a slightly pie-shaped wedge. As the Earth rotates to present a new face to the Moon, the formerly squeezed part of the Earth stretches back into shape.

    While it’s okay to disbelieve, beware that probably hundreds of experiments have borne this out. Despite the observations, the absolute speed of light was widely disbelieved for nearly two decades (too weird to believe!) until Einstein postulated that it was true and made bold predictions thereupon, which have also been confirmed experimentally.

    Like James R said, relativity doesn’t say that. It says that, regardless of your speed towards the light’s source, the light would be going exactly the speed of light toward you. In relativity the speed of light is always the same.

    Good. That’s what we’re here for. If your theory is too wacky, I move on. So far, I’m interested.

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    OK, here’s a question: With your idea, wouldn’t every Moon dust particle, at least those on the surface, need to be continuously receiving at least one gravity-force particle to be continuously pulled toward the center of the Moon? What if some Moon particles were occasionally missed? Wouldn’t they fling out of the Moon’s orbit by their own inertia? And if this were happening often enough, wouldn’t the Moon have an atmosphere of dust?

    Also: how do you explain that the force of gravity has been shown experimentally to be continuous; that is, gravity doesn’t seem to come in discrete packets that would be imparted by a gravity-force particle.

    (I can think of answers within the realm of your theory but I'd like to hear yours.)

    My understanding is that these experiments are measuring the speed of light through various mediums other than a vacuum. Relativity says the speed of light is constant in a vacuum, not necessarily in any other medium. But the main thing to realize is that the speed of light is not a maximum speed limit on how fast you can go; that is, how fast you can attain a destination. Rather, it is a limit on how fast you can be observed to go. Until you grasp the difference, it may seem to be “constant speed of light crap.” After you grasp the difference, it may seem elegant.

    Well put. I’ve thought about this before. The difference is, unlike the car, the particles accelerate in all directions and in a way that brings space to them. Whatever is in the space is brought to the particle, regardless of its size (although the larger particle will appear to dominate). Imagine twin particles A and B. Particle A is accelerating towards itself all its surrounding space, which includes particle B. Particle B is doing likewise. As long as these particles are negligibly distant from each other as observed by a particle C, not necessarily touching, the A-B system will draw particle C at twice the rate of either A or B by themselves. Many particles in close proximity will bring space to themselves as the product of their respective masses, with the caveat that the inward velocity may only approach the speed of light, not attain it.

    You could say that particles A and B are interacting. Or you could say that a particle defines its surrounding space and how it draws that space, including any objects within the space, toward itself. The latter is closest to what general relativity advocates.

    Now you’re getting it! However, Galileo noted that this is no great coincidence if you simply imagine the heavier mass as broken into many pieces each matching the mass of the smaller mass, then drop the many pieces as a group. For example, rather than drop a sand particle alongside a closed box full of sand, drop a sand particle alongside all the sand particles dumped out of the box. Naturally, all the sand particles will fall at the same rate!

    What is more a coincidence is this: When the inertial mass of a standard kilogram (as weighed on the ground) is measured on the orbiting space shuttle, where ground-type weigh scales don’t work, the mass is found to be exactly 1 kilogram.
     
  19. James R Just this guy, you know? Staff Member

    Messages:
    39,426
    zanket,

    I agree with your description of gravitational force vs. acceleration.
     
  20. Frencheneesz Amazing Member Registered Senior Member

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    James R., Picky, picky. I have to choose my words carfully around you!

    -My point was that a force DOES need to act on an object to move it, period. -

    "How do you reach that conclusion? What about Newton's first law? "

    I think when I said "move" I meant accelerate or change the motion of an object. That is Newtons law, I think your just trying to make me look bad.

    -Even if we dont know WHY, we do Know how and if gravity is not a force or have a force mechanism, it can't move something, period.-

    "Why not?"

    Oh come on, This is one of newtons laws. An object's motion stays stagnent unless an outside force is applied. So if there is no force that at least is vaugely associated with gravity. There is no force to change an obects motion, or accelerate it.

    "Oh? I thought this was the "Physics & Math" forum, not the "Free thoughts" forum or the "Pseudoscience" forum."

    I would be very accepting of facts (ie direct observations), but a theory is a theory and is not a prooven fact. I see the advantages of the theory of relativity and quantum mechanics, but you just can't take them for granted. I have to see for myself that the theory works, im not going to take your word for it. That would be unscientific wouldn't it?

    "Could you please tell me briefly what you think is wrong with Einstein's theories which means they need to be replaced?"

    Im sure there are many reasons, otherwise quantum and string theories would not have been sought.

    -I might have already hinted that i don't believe in the theory that light is going the same speed for all frames of refferences. -

    "It doesn't matter what you believe. That is what is observed. "

    I can see your point when you say it doesn't matter what i believe, but i can disagree with your other statement. Light is not observed to travel the same speed in all frames of reference, but deduced from other observations. One really annoying one (for me) is if you look at a picture of a supernova, the super novae expulsions would be throwing newtonion light particles at all different speeds meaning they would come to earth at different times, which seems not to happen.
    That is an observations, and it does not proove that the light wont come at a different time, but it is pretty good evidence for relativity. What are some of the "observations" that you were talking about?

    "Could you please briefly any quantitative predictions your theory makes which differ from the predictions of relativity?"

    Sadly, I don't have a supercomputer handy. Mind lending me one? But seriously, my simple theory would be the basis for deducing complicated theories on everything. But to measure all the precise interactions of the forces and particles would be amazingly hard with a 4 year old computer. I would have to write a program and buy millions of dollers worth of hardware before I could give any quantatative predictions.
    I can give you qualitative explanations for anything that you can think of that doesn't have to do with light. It might be misleading to say that it is a theory, because it is pretty much just a way of simplifying science to make understanding it simpler. I would rather know one equation for math that is a little hard every time to do than have to memorize 20 different equations for 20 similar problems.

    -If you are going the speed of light toward the light, relativity says that the light would be going 2 times the speed of light toward you and vice versa. -

    "Better pull out that relativity text and reread it. That's not what relativity says. "

    OK, ok. I should have said particle relativity says etc. What I mean is that if two spaceships were traveling at the speed of light toward eachother at the speed of light (compared to each's "stop" position) then they would would be closing the distance between them at 2 times the speed of light. This contradicts the way it says light moves, at a constant speed no matter what speed you are going relative to its source.

    -This would mean that there is an intrincic maximum speed limit of the universe, which is rapidly becoming proven inaccurate. -

    "Really? Who has proven it inaccurate? How? "

    OK, you got me. I shouldn't have said that. I could say it is rapidly being debated. You haven't heard of the teleportation experiments? Well, its proof of nothing, but you should see what i mean.

    -More problems sunt: what is light made of, how is it created, and what are photons? -

    "Standard quantum mechanics has a very good model of light. The term "photon" is entirely a quantum beast. "

    Right, i am not a complete idiot. That relativity text needs no opening, but I do want the observations that led to some of relativities insights, like that the speed limit of the universe is lightspeed...
    Also I would like those questions answered: "what is light made of, how is it created, and what are photons? "
    Im sure your expertise would be adequit to answer these. And when I ask what are photons, I mean what composes them. I definately have never heard a "good" model of light, so enlighten me.

    Also, quantum theory has the annoying aspect of probability. Probablity is something we use when we don't have otherwise sufficient tools to evaluate what is actually going to happen. I think if a theory incorperates probability, it is pretty much saying it doesn't know something for certain. For example, the electron "cloud" model is probablity based. I for one think that just because the electrons are going to fast to be measured NOW, doesn't mean it is imposible to measure them in the future. Probability is just nonsence for an incomplete theory.

    "That doesn't provide a connection between gravity and acceleration. It provides a connection between inertia and gravitational mass. That particular connection was unexplained until relativity came along; relativity explains it very elegantly."

    Given that inertia resists acceleration, inertia and acceleration are related. And if you can draw parallels between gravity and inertia, there is a parrallel between acceleration and gravity.

    -end-
     
  21. Fairfield Registered Senior Member

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  22. (Q) Encephaloid Martini Valued Senior Member

    Messages:
    20,855
    French

    OK, ok. I should have said particle relativity says etc. What I mean is that if two spaceships were traveling at the speed of light toward eachother at the speed of light (compared to each's "stop" position) then they would would be closing the distance between them at 2 times the speed of light.

    Wrong again. Relativity does not have a 'clause' labeled "Particle Relativity." Two spaceships traveling NEAR the speed of light (they cannot travel AT the speed of light) towards one another will not attain speeds (2) times the speed of light. Nothing travels faster than the speed of light. Their combined speeds will still be less than c.

    At high velocities, the Relativistic Addition of Velocities formula is used, note that whatever V1 and V2 may be, V is always less than (1).

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    This contradicts the way it says light moves, at a constant speed no matter what speed you are going relative to its source.

    I fail to see a contradiction, please explain.

    what is light made of....

    'Light' is comprised of electric and magnetic fields oscillating transversely in the direction of travel; electromagnetic field (EM field).

    what are photons? "
    Im sure your expertise would be adequit to answer these. And when I ask what are photons, I mean what composes them. I definately have never heard a "good" model of light, so enlighten me.


    Photons are the quanta of electromagnetic fields. They are packets of energy with zero mass. Their energy is related to their momentum. However, for a further explanation, see chapter (4):

    http://www.pact.cpes.sussex.ac.uk/users/markh/RQF1/rqf1.pdf
     
  23. Frencheneesz Amazing Member Registered Senior Member

    Messages:
    739
    "Despite the observations, the absolute speed of light was widely disbelieved for nearly two decades "

    Those observations have escaped me. Do you know what they are? Im sure they are there, but i'd like to see for myself weather i think they are valid to prove it.

    "With your idea, wouldn’t every Moon dust particle, at least those on the surface, need to be continuously receiving at least one gravity-force particle to be continuously pulled toward the center of the Moon?"

    Well, my "theory" won't go into forces, because i simply do not have enough information (nor does anyone i think) to speculated well enough. My theory just accepts that they are forces, but the needed information is what particles create the force (like electrons create electric charge). So far, I think it is beyond science to discover how particle A flung from particle B could pull particle C towards particle B.
    But if there was a graviton, every moon dust particle would presumably be made out of some tinier peices which would all emit gravitons. If the gravitons are emited fast enough then an illusion of continuity would be created. I don't have a good graviton particle theory so I can see flaws in anything i try to come up with. I would suppose that if a graviton did miss, the next graviton that hit it would hit it in such short nitice that it would be pulled back down without jumping very high.
    Again I can see that if a particle could miss then some particles could hit one more than another, but then I could say that the mean of the hits is about equal.

    "how do you explain that the force of gravity has been shown experimentally to be continuous; that is, gravity doesn’t seem to come in discrete packets that would be imparted by a gravity-force particle. "

    I think that was covered in the moon one, but i think that the gravitons would come so frequently as to make an illusion of continuity.

    "Rather, it is a limit on how fast you can be observed to go."

    I think that needs some explaining... for me at least

    "When the inertial mass of a standard kilogram (as weighed on the ground) is measured on the orbiting space shuttle, where ground-type weigh scales don’t work, the mass is found to be exactly 1 kilogram."

    I would say the inertial mass-o-meter is made to calculate it. But I don't exactly know what your talking about. You would have to describe the process of measuring inertial mass. I suppose it would be easy to accelerate an object with a machine at some standard acceleration and then just see how much pressure is with the object.
     

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