Akhenaten2

Just This - since singularities do not exist you can compose them in any way you feel like!

Fair Comment I'll give it more thought - also I've edited my previous posting - any comments?

If I was going to be seduced by this "rescaling" theory I should want to see its curve providing a better fit to observations than the Dark Energy Model it was intending to replace. But it does not. In fact - above a redshift of 0.7 the rescaled curve simply does not provide a good fit at all!!

Furthermore since I predicted several effects in the early 1990's (before D.E. was discovered) that would beset the Voyager and Ulysses spacecraft as a result of an "energy" of this kind - which effects have been patently in evidence and are continuing (for the 2 voyager craft at least) - I'm inclined to vote in favour of Dark energy - at least for now.

I am however, not convinced that the values of several so called "Constants" are actually absolute.

Additionally - you might like to visit Astronomy Now On-Line.

Good point. Though I would say that electromagnetism is due to the geometry of U(1) principle (or associated vector) bundles.

 

Force is curvature!

 

For U(1) we can really make this concrete by adding the curvature to the symplectic form on the phase space of a charged particle and then derive the "free Hamilton's equations" for this modified symplectic form. This is then equivalent to the Lorentz force.

 

 

 

 

The philosophical barrier with gravity is that it "happens on space-time" . (really one should think about natural bundles (or the principle bundles associated with these) over space-time, but as we have a functor from the category of smooth manifold to vector bundles the distinction is not really required) . The EM, weak and strong "happen on bundles over space-time". They don't mess with the arena of the physics. At least not in the same way.

 

I completely agree with you on the need to better understand gravity.

 

One thing to keep in mind is that a definition of force has it's roots in Newtonian ideas. If we require a post-Newtonian notion of dynamics then one would expect the notion of a force will also require modification. It makes me wonder if we should not really get too worried if gravity or the other "interactions" are really forces in any technical sense. We have accelerations or exchanges of momentum and that is enough.

Hooray, Iv'e been trying to get the message over to physisists for 25 years or more, that despite A.E. describing it accurately to us 95 years ago, gravity continues to be still totally MIS-REPRESENTED as a FORCE.

It is of course, an acceleration (which means it mimics and can be calculated as if a force) but never-the-less is not a force. Once you accept that you can start making sense of everything.

"We have acceleration or exchange of momentum and that is enough"

What kind of complacency is this?

What about the billions of dollars and vast resources, being wasted on the futile search to unify gravity as a 4th force (the incredible weakness by comparison should be enough to realise it is not a force) with the other 3 forces of nature? What about all the mis-conceived experiments designed to find effects of a force which doesn't exist. Gravitons? - I ask you!!, Gravitinos? I ask you!!! - Total rubbish!!!

For example - Gravity waves exist, but there is no way they can be detected by deflecting mirrors or other 'mechanical' devices.

"LIGO" is a complete waste of time, as Iv'e I've already told them.

GRAVITY IS NOT THE PRIME MOVER OF THE UNIVERSE!! - it is merely an effect!!! - This is probably all I'm prepared to say at the moment.

It is.

Don't worry, the vast majority of people agree with you. I dont', but I'm in a tiny minority. However that includes, besides me, Michio Kaku, Neil de Grasse Tyson, who have both said so on TV recently + a few other notables doing similarly + that other chap - er what's is name? I forget now! - oh yes that's it a Mr A. Einstein!!!

No John, I haven't missed any point. Its not about size its' about the amount of light. The "apparent" brightness of your torch (at 2.5 mtrs) is far, far greater than that of stars. There is little comparison between your torch-lit pinhole and star-shine except in your imagination.

Many photons will get through, but many will be refracted in the atmosphere to peripheral areas to the main image and seen as colours, many similarly lost and some reflected back into space.

If you look at the EM, weak and strong nuclear forces, when they lower potential, energy is given off. If gravity is also a force, like the other three forces, one would expect gravity would also give off energy when it lowers potential.

 

For example, if an electron lowers energy, a photon is given off. This photon can hit another atom and knock an electron to a higher energy level. The energy output has an anti-EM effect on other atoms.

 

If gravity is a force like the rest, when gravity lowers potential it should give off energy, which can increase the gravitational potential elsewhere. In the case of the universe, the summation cause it to expand.

 

Say we had a clump of matter in space that is collapsing to form a star. Since the gravity potential is lowering, the theory says energy will be given off at the same time it collapses. The combined effect would be collapsing and spinning.

 

The acceleration expansion of the universe would imply that the amount of matter in the universe, lower gravity potential into galaxies, stars, planets, blackholes, is increasing over time. Are there more galaxies and stars now than 10 Billion years ago, 5 billions years ago, etc.?

 

Since the matter of the universe tends to clump within galaxies, the bulk gravity energy output should have a connection to these largest bulk sources, causing the universe to expand relative to the galaxies.

 

Dark energy is the energy output stemming from gravity. Dark matter is predicted from the equivalence of matter and energy.

And if Gravity isn't a force?

John - re post 67. - "You can see an arbitrarily small thing, provided it's bright enough."

This was an interesting experiment you did; could you complete it for me?

By my calcs your distance/size relationship is out by a factor of about 100 (for a sun size object about 4 ly distance). Also your torch brightness could be out by a similar factor.

So if you repeat the set up, but with the torch and pinhole (a more appropriate) 250 meters away, without brightening the torch but additionally shining the light down a small bore tube onto the pinhole (to simulate more of a point source) - please advise if you can still see it.

Wait, what? Relativity says no such thing.

 

Relativity tells us that motion is relative. Its perfectly acceptable to say something is at rest, and there is no physics you can do that will tell you that something is in a state of motion. There is no claim about things not existing if they are at rest. Where did that come from?

My apologies to everyone. I made this throw away comment, which I thought everyone would understand. It turns out to be highly controversial and I didn't think to revisit and substantiate it. Naughty of me, but the thread has developed too far for me to respond on any but a general basis.

Actually this should not have caused any controversy. My comment is a true and accurate comment about Relativity theory, but perhaps many have trouble seeing this connection.

Firstly, one of you physisists should by now have pointed out to everyone that both the Special and General theories of Relativity are actually theories of MOTION and (more to the point) the motion of the universe. SR describes the behaviour of objects moving at constant velocity and - to briefly quote J.Cribben from Q is for Quantum - "GR deals with accelerations, which is why it is more general, BUT CRUCIALLY is ALSO a theory of gravity. The cornerstone of GR is the 'equivalence principle' which says that Acceleration and gravity are precisely equivalent".

I think we should all now conclude that Relativity theory is ALL ABOUT MOTIONS.

GR only became an "acclaimed" theory of gravity after 1919 when Einsteins calculation of the bending of light by the sun, was confirmed ahead of Newtons. It was not widely accepted as the definitive theory of gravity until much later.

If Mercury did not exist, or had been behaving in line with Newtonian gravitation, Einstein might never have looked for an alternative explanation for its "strange" motion relative to the sun.

So it would be quite legitimate for me to claim I only meant that, without motion, Relativity theory wouldn't exist. But of course that is not quite what I intended.

Einstein theorised that its motion could be explained if Mercurys' mass-energy was interacting with an all pervasive field of "Space-Time" emanating from the sun.

In doing so he quashed any idea that any 'force of attraction' was causing this motion. This was 95 years ago.

He realised that his discovery further implied that all clumps of matter in the universe would behave similarly, because the "Principle of Relativity" (the laws of physics are the same everywhere) says everything must be in motion relative to everything else and all must contribute proportionately to the overall "background" of space-time.

To be cont...

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cont....

Einsteins' field equation relating this mass-energy to space-time, indicated to him that the universe should be either expanding or contracting. It couldn't be static. Almost everyone on the planet, at that time, believed that the universe (on a non-local scale) was totally static.

He was therefore entreatied to modify his equation to nullify this "unseemly"motion. To do this he invented and added to the field equation, the "infamous" cosmological (or lambda) constant (more properly a small acceleration of undetermined sign - or put more simply one motion to stop another)

Clearly AE was preoccupied with 'Motion' and preoccupied enough to risk devaluing his most important lifes-work.

Both Special and General Relativity are now well proven theories.

Cribben comments:- "There is no doubt the General theory is a good and accurate description of the behaviour of matter in the universe and of the relationship between space, time and matter." He goes on to say - " One of the most important features of the general theory, is that it provides a COMPLETE description of the universe and of the way the universe has expanded away from a "singularity" (I might argue with him here) at the beginning of time, via the Big Bang, to reach its present state."

This is the expansion of ALL the universe; everything in the universe; from the instant of the BB, through any inflationary expansion, subject always to gravity and now (we realise) Dark Energy.

Trust me - if its in the universe - ITS MOVING - there is no tenable option - GR says so!

If it isn't in the universe now, it never was and therefore does not exist in our reality. GR implies so!

This also ligitimately answers all criticism of my comment - but is still not my full response.

TB cont...

I don't think that argument holds water. If the photon flux was so small that you don't get multiple photons on a receptor (in some arbitrary time), how does spreading it out via atmospheric effects make it appear brighter?

I think Iv'e explained perfectly well how and why atmospheric effects only enhance the ability of humans to observe stars on earth using our "less than perfect" eyesight and its (slightly time-lapsed) relationship with our "less than perfect" brains - not that they add to their brightness.

This topic was raised during the Apollo era and has arisen several times since - mostly in relation to debunking theories. I have related what I recall to be the consensus view. To the best of my recollection very few (possibly none) of the astronauts either on the moon or in orbiting craft, recalled seeing stars when interviewed.

I wouldn't be surprised if somewhere deep in the NASA archives is a poorly exposed image from the Moon, with the lunar landscape bright white and washed out and stars clearly visible. They were manual cameras operated by guesswork, so they probably screwed up a few images. We only get to see the nice ones.

yes exactly - overexposed.

No there's nothing else. The question was would you "notice" them on the moon rather than 'can you see them'. I think you have helped me explain that they would not be as noticeable on the moon for the reasons I (and you) have now laid out. So thanks for that.

Ah, but we don't know if the observer is measuring at noon, sunset or sundown, or where on the surface the light is coming from.

I stand corrected Swansont I didn't think it worth bothering with adjustments for tiny earth/sun differentials - I'll amend my 'estimate' to "about 2.4 seconds + or - about a millisecond. OK?

Your comments regarding the varying positions and times of observers and where the light originated from, have no bearing on the original concept of the discussion.

I still don't see how the twinkling makes a lot of odds. In the absence of an atmosphere the photons will all hit the same receptor cell. They will, therefore trigger it. You will see a bright spot.

On a clear night the stars don't twinkle much- occasionally you get clear spots of air. The stars don't "go out" when this happens

John, your'e not listening to either me or Mr Skeptic, earths atmosphere makes all the difference!!! Stars (at the distances involved) are much tinier than you can clearly conceive and their light behaves only as a point source. Earths atmosphere, whether twinkling or not, smears out this tiny amount of light (as I have described) and makes them appear much bigger than they actually look in space.

You need to read a bit about eyes, receptors and quantum behaviour to appreciate the very low probability that even two photons from a "point source" would hit the same receptor cell. Even if they did, receptors are so small you would barely notice.

I personally do not see twinkling of stars. However, they say it is caused by our atmosphere and fluctuations in it, because the stars are pointlike sources. The planets are not supposed to twinkle since they are not pointlike sources. But maybe I'm blind cause I can't see any difference.

I apologise, I understood all human eyes to register the twinkle similarly, but I accept this could be only a majority. Logically it might depend on where you live and where you observe from. I can see that people at altitude or in areas of low atmospheric disturbance, would see less twinkling than at sea level or heavy atmosphere generally. The planets and stars all twinkle for me too, though I understand that the planets are not supposed to. Maybe atmospheric pollution is starting to vary this phenomenon differently?

Oh, that would be interesting indeed. If the entire universe were rotating, then it would have a center and we would be able to find it, right?

Conventional "wisdom" says the universe has no centre, but in fact I have arguments against this (All proprietary info I'm afraid at the moment). The indications from CMBR images is that if there is rotation it is very small, but if there is any rotation at all, then in principle it must be about something.

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It may be just me but can you explain this

"This is not the case on the moon, where the photons arrive effectively one at a time in a very narrow stream and hence only excite a small number of receptors. Each receptor only registers the signal for a short time so you only get a faint and largely incomplete image."

As far as my eyes are concerned the stars are point sources. The light from them arrives at my eyes along a very narrow line.

The moon has no atmosphere to scatter photons. A slightly larger number of photons would reach my eyes on the Moon than on Earth.

The " we never went to the Moon" nutters say that the lack of stars in the background of pictures taken on the Moon proves that we weren't there.

Cleverer people point out that it's just the same as on earth- you don't normally see stars in a picture where the exposure is set for daylight.

If you face away from the sun and look up at the stars while on the Moon they should be just as visible as here on a dark night.

The stars are just as bright (actually slightly brighter) and the background just as black (actually slightly blacker).

Just as many photons (strictly, slightly more) hit the retina and, I suspect that they pretty much all hit the same receptor cell- much as they do on earth.

What's the difference?

Then I'm afraid you have unique eyes - everyone else on earth sees them twinkling which is caused exactly as I have described. The stars themselves do not change it is only the amount of light which is registered exactly the same as I have told you. Seek an alternative source if you do not believe me. Photos on the moon would have to be considerably time lapsed to register images.

I defy you to hold your head still enough to get all the photons striking anywhere near to just one receptor- here or on the moon.

Indeed. Aphelion is 152,097,701 km and perihelion is 147,098,074 km, so it varies from ~490 to ~507 seconds. Rounding isn't that big of a sin if you are ignoring these other details.

I agree with you entirely on this Swansont. Rounding to 8 mins sounds all right to me, but I'm sure you'd want me to point out that all the distances you quoted are between centres of mass and the light actually comes from the suns surface. You need to subtract about 2.4 seconds.

Light coming from the suns centre of mass takes thousands of years to "wriggle" out.

"The "stuck" orientation/motion you say you find weird and cannot understand, is actually quite common. A number of the larger moons in the solar system exhibit similar gravitational binding to our moon."

Gravitational locking is perfectly commonplace and I'm familiar enough with it.

 

What would be odd would be if the moon were "locked" to the rest of the universe, rather than rotating in it.

 

Incidentally, because there's no atmosphere the view of the stars from the moon should be excellent. It's silly to say "Because stars are so distant, each is just a pinprick of light " they are practically as far away from Earth and they are practically pinpoints from here too. In most cases they are so small that all the light from a given star falls onto just one retinal cell; it wouldn't matter if the Earth's atmosphere were removed- they would still be points as far as the human eye is concerned.

If you are on the moon you should be able to see them rise and set - albeit very slowly.

Of course it would be easier on the dark side of the moon (and I mean dark, not Earth-facing)

What would be more interesting is if the universe itself turned out to be rotating - we wouldn't be able to trust any observation we ever made!

I'm afraid what I said about not detecting stars so readily on the moon is perfectly true; Though you would see some of the nearer/ larger ones rise and set slowly and make out larger structures reasonably (eg The Milky way galactic features).

Earths atmosphere smears out the stream of photons of light from stars and thus we are able to observe them better but the downside is that twinkling and colour scatter occurs. Being smeared out means that some refraction effects are occurring which slows some photons more than others and this holds the image together long enough for our eyes to register a larger number of photons over a larger area of receptors.

This is not the case on the moon, where the photons arrive effectively one at a time in a very narrow stream and hence only excite a small number of receptors. Each receptor only registers the signal for a short time so you only get a faint and largely incomplete image.

If earth had no atmosphere this is all we would see from here also.

Thanks shakes - digipro was interesting but nothing new and nothing to resolve this thread question I'm afraid.

Thanks Sisyphus

I've found one or two of your comments to be a bit wide of the mark, but I agree with you on this last comment. I will leave people to consult wikipedia for the answers that I consider less contentious or (dare I say) - "beyond dispute".

I in fact, try to concentrate my comments (in language we can all understand) to material that isn't contained in such scientific edicts. This is because I have an enquiring mind and I do not find it satisfactory to be told to accept something just because a majority of people believe it to be true.

All such "wiki - type" articles are written based on the "best interpretation currently to hand" of the physics involved. But if there is a fundamental misconception running through the "establishment view" then how are we ever to understand and expose it if we are only ever allowed to "consult" the "establishment edicts"?

Regards - Akhenaten

If I get a good analytical balance and calibrate it at the equator then move it to the North pole it needs recalibrating. Part of that change is because the Earth isn't a perfect sphere, but part of it is because the Earth rotates.

I can do that experiment without needing to know about anything else in the cosmos or relativity and I can deduce that the Earth spins.

Similarly I can set up a Foucault's pendulum and, from its motion I can tell that the Earth is rotating.

 

What would be the outcome of doing these experiments on the Moon?

My guess is that would show the Moon to be rotating once a month.

I also guess that that is a lot nearer to the sort of answer that the OP wanted.

John,

I apologise, I answered this in haste and it was ill conceived. Having now partially re-examined your "Moon experiment hypothesis" I conclude that a rotation would be recorded. However, in view of the peculiar geometry of the sun/earth/moon system and its several sets of precessional effects, the moons motion becomes very complex.

Using either a gyro or pendulum alignment at the moons poles would record a lunar 'sidereal' month of 27.3 days and this is generally taken to represent a true rotational period. I contest this in a gravitationally bound situation.

The counterpart experiment on earth (viewed from its clearly rotating and therefore 'non-inertial' reference frame) introduces the "Coriolis" and 'Centrifugal' "pseudo forces" which cause the observed periodic deflections in the apparatus.

The same set up on the moon would similarly constitute a non-inertial reference frame and this would similarly introduce pseudo forces to create the deflections which would be seen in that apparatus also, but (I emphasise) this would only be recording the "revolution" of the moon about its orbit - as compelled by earth/sun gravity - and not an actual rotation of the moon about its own axis.

Regards

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We has people on the moon for a while; did they notice any stars rise and set?

(come to think of it, did they leave a telescope and transmitter of some sort behind?)

If not then it seems to me to be really weird that the moon is "stuck" in one orientation whereas everything else we see seems to have a spin.

John

Astronauts on the moon could still observe stars rising and setting due to orbit change, but they might possibly not have "noticed" them because you get a very different view of stars on the moon. There is no "Twinkle" effect.

Because stars are so distant, each is just a pinprick of light and requires at least a small time lapse to register. Normal photographic shutter speeds are probably too quick and probably our eyes are too.

I honestly don't know what they left on the moon.

The "stuck" orientation/motion you say you find weird and cannot understand, is actually quite common. A number of the larger moons in the solar system exhibit similar gravitational binding to our moon. It is also common among binary star and star/BHole systems and even evident to a degree in the planet Mercury, which (according to conventional teaching) is bound into doing 3 rotations to every 2 orbits. They all spin relative to some axis or other but not their own. In all cases they must "share" an axis with a larger body.

Swansont/Iggy - Gentlemen before you congratulate yourself too early on a job not even nearly done I have a few things to say. In no way has the original question in this thread been answered.

When I first saw Pravin.sonars simplistic question I didn't think he had just got up that morning and thought "I wonder if the moon rotates". I expected that he had been pondering it for some time and hadn't found many answers that satisfied.

I was surprised that it (initially) received only a brief, scornful response, because I felt ( as is being proved) that it was a rather interesting and profound question which was by no means unequivocal. This kind of handling is what "drives people away from science" I believe.

I have long held the view that there is a deep misconception bound up in this seemingly innocuous query (and many others). I strongly disagree that this should be viewed as a rotation about its own axis and neither of you have found any argument that convinces me otherwise.

Swansont - I feel you are peddling the "Newtonian" viewpoint because this best suits your arguments and your reluctance to "invoke relativity" is more because It doesn't.

Then we have Iggy coming in with a sledgehammer to break an egg and invoking Totally Irrelevant relativistic effects I suspect he does'nt understand a great deal more than I do; talking as if the sun were a black-hole and not really contributing to the discussion at all.

This approach too is the kind of handling which "drives people away from science"

Iggy you say you don't get this "It either rotates or it doesn't" bit, well from what you have said, I defy anyone to decide categorically whether you agree with rotation or not. I don't get why such clever people can be so ambiguous. It's almost as if this is the intention in science today and this too drives people away from science.

I haven't time tonight, but I think everyone who has commented, deserves an answer of some sort and I shall try to do this in due course before I respond more appropriately to your combined comments.

Perhaps pravin.sonar could, at this stage, say whether he is forming an opinion as to what conclusion he can draw.

Regards for now -Akhenaten

John - My guess is that it won't, but we will probably not now find out in our lifetimes.

Swansont - Thanks for your patience under duress - I thought I had mastered the posting and have just spent 2 hours composing an extensive response, which had my 3 strongest arguments that might have "stirred" you also, but this is all now somewhere in cyberspace - I can't afford any more time on this topic - we must agree to disagree. I've enjoyed our discussion.

Regards - Akhenaten

Try it. Take a gyroscope and move it around a circular path, whose axis is perpendicular to the gyroscope's axis of rotation, without exerting a torque on the gyroscope. We know the gyro won't rotate, so that's what non-rotation looks like. The gyro axis maintains a fixed attitude toward a distant, fixed object. The moon doesn't do this.

This is all very interesting, but mostly diversionary from the original discussion about the moons orbital/rotational motion. I understand what you are saying and if the moon actually rotated additionally as a gyroscope, with axis perpendicular to axis of orbit, everyone who ever lived would swear that (from our perspective) it also rotated bodily once backwards every orbit. The question of whether it rotates would never have been asked. But the moon is gravitationally bound (which I feel is the essence of the problem) is not gyroscopic as it does not rotate about its supposed axis of rotation (at least not more than slowly) and its supposed axis of rotation is parallel to the axis of its orbit. So I cannot accept that your analogy is in the least valid.

In my reference to Uranus, which does exhibit some of the properties you describe, I ask (genuinely) will its gyroscopic-like spin orient it in the same attitude all the way round its orbit?. If so, will we describe this as one backward bodily rotation?

I did not realize we had gone through the looking glass.

 

"When I use a word," Humpty Dumpty said, in a rather scornful tone, "it means just what I choose it to mean - neither more nor less."

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OK, let's look at that situation. You have your (track & field) hammer and because we want to make sure it doesn't rotate about the axis in question, we put a gyroscope inside, perpendicular to that axis. Now, can we swing the hammer only via a force along the arm, i.e. perpendicular to the sphere?

 

I think you'll have a hard time doing that.

Perhaps, perhaps not. The weight doesn't rotate about its axis so the insertion of the gyroscope is merely an attempt to prevent the weight being rotated about the athlete. I doubt the gyroscope could be made large enough to prevent this though. But do we not have proof of this in the planet Uranus, which has a "gyroscopic-like" rotation but still follows a low ellipticity orbit despite its axis of rotation being almost perpendicular to its orbital plane. Is this proof that the Newtonian view of gravity, as a force between centres, is not correct?

obviously you do not need me to point out that these 3 "observations" are merely unavoidable consequences of proven natural behaviour. Living is dangerous after all. You would need to forecast exact instants and circumstances to claim an "observation"

I'm perfectly satisfied the future does not exist.

I totally agree with your last sentence - this is a must because a proper understanding would confirm my previous sentence.