Photons VS.Higgs-boson particle

Discussion in 'Astronomy, Exobiology, & Cosmology' started by machiaventa, Jul 9, 2012.

  1. hansda Valued Senior Member

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    No such bending of particle photon is observed around the Earth or the Moon in lunar or solar eclipse.
     
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  3. hansda Valued Senior Member

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    Here, three things are involved : an astronomical mass, spacetime and particle photon.

    So, there can be three relationships between (1) astronomical mass and spacetime, (2) astronomical mass and photon, (3) spacetime and photon.

    As per GR, spacetime always curves around the astronomical mass to generate gravity for the astronomical mass.(1)

    Particle photon may or may not curve around the astronomical mass.(2)

    The relationship between spacetime and photon (3) is quite different from other two relationships.


    What do you mean by photon's frame of reference? Is it part of photon or an outside observer?
     
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  5. OnlyMe Valued Senior Member

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    This is an example of the problem. The curvature of spacetime within the context of GR cannot be explained, by the everyday definition of curve you are using.

    Within the context of SR, length and time are dilated, and within the context of GR space (being a more complex form of lengths or distances) and time are dilated. In each case the dilation of distance and time is what the curvature of space is all about. Not the everyday definition of curve...

    In SR it is not generally talked about as curvature, because length contraction occurs only in the line of motion.., only relative to an object's velocity and only in the direction of that velocity. In GR lengths are contracted in all three spacial dimensions or directions.

    The way a gravitational field affects lengths is what the curvature of space in GR terms is about. Space does not in any real sense bend around a gravitational mass, in the same way a road curves or bends around a corner. What is happening is that distances on the x, y and z axises are all contracted or lengthened and time is dilated.., compressed or stretched, relative to where in a gravity well you are. The effect is very small except when you are considering a strong gravitational field, as in very close to our sun.

    Its location in the Earth's gravitational field, causes a GPS sattelite's clock to run fast, by a few tens of seconds per day (in 24 hours). That is in the neighborhood of a 0.04% change and accounts for both the GR and SR effects. To get an idea of how much that same gravitational influence would affect light, think about how far light would travel in 30 or 40 seconds.., and how difficult it would be to measure a 0.04% change in its direction, as seen from an outside perspective.

    The situation is really far more complex than just that. It is also very difficult to discuss without the mathematics, or in everyday lay language and analogy. To go further, I think would only add complication. First try to build a conceptual image of the curvature of space/spacetime, that is based on how gravitational fields affect length and time, instead of the two and three dimensional terms we use to describe everyday objects and actions.

    The photon's frame of reference is the frame one would experience if it were possible to move along with the photon. In all real situations we are always observing photons and light from our own frame of reference and measuring. Though I don't believe it is really accurate, one could say that from the photn's frame of reference, it is standing still and the universe is moving past it at c.

    The original point was that from the perspective of GR and curved space/spacetime as described above, the photon's path does not "bend". Though from where we view it, it does appear to do so. We cannot see how space/spacetime is changed or curved, by proximity to a gravity field, so we "see" the path of a photon from an outside perspective and it appears to bend around an object.

    I am sorry if any of the way I have been trying to explain this is confusing. Like I said earlier it is very difficult to discuss in everyday lay orientated language. I think if you can get one thing from my feeble attempt above, it would be to think of the curvature of space/spacetime in terms of length contraction and time dilation, instead of the curve of a line on paper or how a road curves around a hillside.
     
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  7. hansda Valued Senior Member

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    So, curvature of spacetime around an astronomical mass is in 4D but curvature of photon due gravitational lensing is in 3D.

    There is no such gravitational lensing around the Earth or the Moon(otherwise there would have been evidence in eclipse time) , though there is evidence of gravitational lensing around the Sun. As per GR, spacetime curves in 4D around the Sun, the Earth and the Moon.

    So, this is not gravity or curvature of spacetime in 4D; which causes gravitational lensing otherwise curvature of photon(gravitational lensing in 3D) around the Earth or the Moon would have been observed in eclipse time.
     
  8. OnlyMe Valued Senior Member

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    First, 4D is just 3D + time. They are just different geometrical models, used to approximate what we experience and observe. This is part of the reason I keep using, space/spacetime, in many of my posts. I try to bridge that gap, in how 3D and 4D seem to be misunderstood, as describing different things. They describe the same thing in different ways.

    How would you expect that we could observe any gravitational lensing around the earth? We are on the earth! As for the moon..., try once more to imagine just how much smaller the gravitational lensing around the moon must be, when comparred to the sun. We can observe the lensing effect around the sun because, the light passes close enough that it is affected by... Wait for it ... A strong gravitational field, which the moon cannot duplicate.

    Gravitational lensing occurrs to some extent around all, yes I said all.., gravitational masses. Except in the case of a STRONG field the effect is far too small for our ability to detect it. We detect lensing around the sun, galaxies and in some cases where we believe there is dark matter, sufficient to create a detectable lensing.

    The moon is just too small and we are on the earth, so we can see only the light that hits the earth, not that part that does not!
     
  9. hansda Valued Senior Member

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  10. OnlyMe Valued Senior Member

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    Hansda, I am about ready to give up on you. During that kind of eclipse the light from the sun would still overwhelm any photon passing near enough the earth to experience gravitational lensing.., even if the effect were within our ability to detect it.

    The gravity well of the earth is just not that strong....... And the moon has only a fraction of the gravity the earth does.....
     
  11. AlphaNumeric Fully ionized Moderator

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    Please provide source for such a claim. Please provide a link to a paper, published in a reputable journal by a competent research group, which does a sufficiently accurate observation of light deflection about the Moon to test relativity and which finds no such deflection. If you cannot provide such a thing then your assertion is baseless.

    You obviously have no idea what curvature in general relativity is, so all of this asserting you're doing is based on nothing but your opinions, not sound reasoning.

    We have measured relativity effects about the Earth and Moon via the GPS network, Gravity Probe B and gravitational redshifting. Precisely the results expected by general relativity were observed. At the very least this falsified Newtonian gravity again and demonstrated that GR can explain things no other model of gravity currently known can. The GPS network measures gravitational and motion based time dilation. Gravity Probe B tested the geodetic effect. The Pound-Rebka experiment tested gravitational redshifting in the Earth's gravitational field directly. We've since been able to do similar experiments planet to planet via probe communications.

    Every single experiment which has aimed to test the predictions of general relativity about the gravitational fields of the Earth and Moon and Sun has confirmed the predictions of relativity. You have asserted no deflection due to the Moon has been observed. This is different from the experiment not being done, you're implying it has been done and it failed to give the expected result. Provide a reputable published, peer reviewed experiment which justifies that claim of yours.
     
  12. hansda Valued Senior Member

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    My claim is based on wiki diagram on solar and lunar eclipse. These diagrams does not show bending of photon around the Moon and the Earth.

    The links for the wiki diagrams are http://en.wikipedia.org/wiki/File:Geometry_of_a_Total_Solar_Eclipse.svg , http://en.wikipedia.org/wiki/File:Solar_eclipse_types.svg for solar eclipse and http://en.wikipedia.org/wiki/File:Geometry_of_a_Lunar_Eclipse.svg for Lunar eclipse.
     
  13. OnlyMe Valued Senior Member

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    Hansda, those diagrams from Wiki are not meant or intended to show any gravitational lensing.

    I don't believe that the Moon's gravitational field is strong enough for us to measure any lensing, though it most certainly would occur. The same is true with respect to the Earth's field when viewed from the moon.

    You are taking the diagrams completely out of context. The geometry they are talking about is not defined on a scale that would include any lensing effect, even were it detectable.
     
  14. AlphaNumeric Fully ionized Moderator

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    Seriously? SERIOUSLY?! You do know they are only schematic diagrams, right? For example, the Moon, Earth and Sun aren't really that close relative to one another's size. The Sun isn't really that size compared to the Earth. They are massively simplified diagrams to get particular concepts across.

    Besides, the deflection the Moon imparts on the light is so tiny that on such diagrams the curve would be indistinguishable from a straight line so for all you know, it may well be drawing the correct curvature, it's just too small to see. Well done, you're doubly wrong. You need to realise that doing a Google image search doesn't make your assertions scientific, it instead demonstrates you don't have any actual knowledge or experience in any of this stuff and you just clutch at straws.

    The fact of the matter is that every experiment for general relativity's predictions about gravity has been validated. Your claim is that the deflection about the Moon doesn't occur. To justify such an assertion you need to either do the experiment yourself, compute the predicted deflection from GR and then compare or you need to give a link to a paper where someone else does that in a competent manner. The fact you reached for an obviously simplified schematic diagram of an eclipse shows you don't have any idea what 'justified' means in science.
     
  15. hansda Valued Senior Member

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    2,182
    Particle photon may bend around the Earth but no such bending of photon was considered in the calculation of 'maximum possible duration of total solar eclipse'. See this link http://articles.adsabs.harvard.edu//full/2003JBAA..113..343M/0000343.000.html .
     
  16. LaurieAG Registered Senior Member

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    If you actually map out the path of a stream of photons emitted from a rotating source, heading in a straight line from the emission point to the observer as the source rotates, you will see that the path is curved without any other gravitational mass required apart from the mass required to keep the original source rotating and emitting in the first place. Say you were viewing a star that took 200k years to rotate around its galactic center from an observation point 200k ly away.

    If you plot where the light path from the source to observer is at each of the 4 quadrants of the galactic rotation (A, B, C and D) at the time of the observation you will expect (1) to see the photons from the first quadrant A coming into the observation point, (2) the photons emitted from position B to be 50k ly away at a point in a direct line to position B, (3) the photons emitted from position C to be 100k ly away at a point in a direct line to position C, (4) the photons emitted from position D to be 150k ly away at a point in a direct line to position D and the original start point of the rotating source A is at the end of this twisted light path here and now after one complete rotation.

    Joining up these 4 points gives us a curved light beam path that exists in discrete real time. It cannot be a straight line even though it is comprised of quanta of straight lines, regardless of whether the source is moving away from or towards the observer at the time of observation. Somehow I don't think its a good idea to turn Schrodingers box into a refrigerator and claim that the light is always off when the box is closed.
     
  17. hansda Valued Senior Member

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    2,182
    Here is another paper, which observed some anomaly. See the link http://relativity.livingreviews.org/open?pubNo=lrr-2001-4&page=node10.html .

    Following is the quote from the paper
     
  18. AlphaNumeric Fully ionized Moderator

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    It isn't included because the deflection is too tiny to bother with. We're talking about fractions of a second here. Small fractions.

    You don't seem to realise there's a difference between "This effect is not relevant to our calculations, as we don't go to such huge levels of precision" and "This effect doesn't exist". If you want to hit a target across a room with a laser you could do the light deflection GR calculations but you'd be doing a ton of work to compute a deflection beyond your ability to measure. This is how science is done, careful consideration of the relevant contributions and errors is essential.

    Same thing, you've ignored the fact experimental error is often so big it swamps such things. For example, if you have a clock which is only accurate to 0.1 seconds then you cannot build a GPS network, as you cannot accurately measure timing differences. This doesn't mean the differences aren't there, it means you cannot measure them. Besides, you're being extremely dishonest by quoting a paragraph which admits large experimental errors but then failing to acknowledge the following paragraph goes on to explain how better, more accurate equipment went on to narrow down the errors and confirmed relativistic predictions. Either you stopped reading that page when you read what you think supported your claims, which is both dishonest and stupid, or you did read the paragraphs which followed, explaining how better experiments supported relativity, and you just decided to ignore it. That's less stupid but much much more dishonest.

    If this is an example of how you 'cite' sources then it completely undermines your previous referencing of other sources because you obviously have no qualms about being deliberately and wilfully dishonest. If you cannot support your case without resorting to lies then no one should give you the time of day. It's a deliberate act to either stop reading or ignore what you've read, either of you must be consciously aware of. As such, why are you doing it? You know you're ignoring information which contradicts your claims. What's your reason for not only trying to deceive others but also lying to yourself?
     
  19. hansda Valued Senior Member

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    2,182
    Does it mean that spacetime is almost flat around the Moon or curvature of spacetime around the Moon is so small/tiny that it is insignificant and spacetime around the Moon can be considered as flat?



    My only intention is to confirm, whether bending of photon is due GR or frame-dragging effect or due some other effect.
     
  20. OnlyMe Valued Senior Member

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    It means only that the curvature of space/spacetime resulting from the gravitational field of the moon is too small for "us" to measure it, at present. It is still there, but it would be like trying to measure the diameter of a hair, with a yard or meter stick.

    Frame-dragging is predicted by and part of GR. It is not something separate.

    When compared to gravity itself it seems to be a very small effect. Think of it like this, the effect of frame-dragging is hundreds of times smaller than the effect of gravity itself... Or like this the Grabity Probe B experiment measure frame-dragging in milliarc seconds per year, while if the sattelite were not in orbit and allowed to fall straight to earth, under the influence of gravity, it would have been measured in hours, at most. It was only about 400 miles up, in orbit.

    Yes frame-dragging would affect the path of a photon passing a gravity well, but that effect is far smaller than the general effect of gravity itself.
     
  21. hansda Valued Senior Member

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    2,182
    So, you mean to say practically, spacetime is flat around the Moon.



    Do you mean to say that, 'curvature of spacetime' and 'frame-dragging' are same?

    You have any reference for this?

    Can you show reference for this statement?
     
  22. hansda Valued Senior Member

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    2,182
    So, is it that in the case of the Moon; almost flat spacetime generates gravitational force for the Moon?
     
  23. OnlyMe Valued Senior Member

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    Hansda, you want to know what causes gravity. There are some very interesting ideas comming out of quantum mechanics, but none have been entirely successful, yet. Both Newton's and later Einstein's theories, only describe how gravity affects objects. They describe what is happening, not how it is happening.

    GR says that gravity is the curvature of space, but does not really explain how, it gets curved or how that curvature causes two objects to be pulled together. Newton flat out called the force of gravity action at a distance, between two objects, and never tried to explain how. I don't think even he liked the "action at a distance" lable.

    Newton's theory says space and time are flat, and it works very well describing most of what we see and attribute to gravity on earth and in the solar system. It could not explain some fine details, like Mercury's orbit, I believe even Newton understood that. Einstein's GR does explain Mercury's orbit and much more, though is does have some difficulties at cosmological scales.

    So is space flat? No! But for the purposes of quantum scales, everyday experience and most of what we see in the solar system, the difference between assuming space to be flat or curved is too small to detect.

    Still, no one so far can say with certainty what causes gravity, though we can describe with great precission how things interact because of gravity.

    Within the context of GR space is curved even around a rock on the ground in front of you, but that curvature is so small that it is insignificant.
     

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