Stanford’s Gravity Probe B confirms two Einstein theories
After 52 years of conceiving, testing and waiting, marked by scientific advances and disappointments, one of Stanford’s and NASA’s longest-running projects comes to a close with a greater understanding of the universe.
Stanford and NASA researchers have confirmed two predictions of Albert Einstein’s general theory of relativity, concluding one of the space agency’s longest-running projects.
Known as Gravity Probe B, the experiment used four ultra-precise gyroscopes housed in a satellite to measure two aspects of Einstein’s theory about gravity. The first is the geodetic effect, or the warping of space and time around a gravitational body. The second is frame-dragging, which is the amount a spinning object pulls space and time with it as it rotates.
After 52 years of conceiving, building, testing and waiting, the science satellite has determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth. If gravity did not affect space and time, Gravity Probe B’s gyroscopes would point in the same direction forever while in orbit. But in confirmation of Einstein’s general theory of relativity, the gyroscopes experienced measurable, minute changes in the direction of their spin as they were pulled by Earth’s gravity.
The findings appear online in the journal Physical Review Letters.
“Imagine the Earth as if it were immersed in honey. As the planet rotated its axis and orbited the Sun, the honey around it would warp and swirl, and it’s the same with space and time,” said Francis Everitt, a Stanford physicist and principal investigator for Gravity Probe B.
A lasting legacy
“GP-B confirmed two of the most profound predictions of Einstein’s universe, having far-reaching implications across astrophysics research,” Everitt said. “Likewise, the decades of technological innovation behind the mission will have a lasting legacy on Earth and in space.”
Stanford has been NASA’s prime contractor for the mission and was responsible for the design and integration of the science instrument and for mission operations and data analysis.
Much of the technology needed to test Einstein’s theory had not yet been invented in 1959 when Leonard Schiff, head of Stanford’s physics department, and George E. Pugh of the Defense Department independently proposed to observe the precession of a gyroscope in an Earth-orbiting satellite with respect to a distant star. Toward that end, Schiff teamed up with Stanford colleagues William Fairbank and Robert Cannon and subsequently, in 1962, recruited Everitt.
NASA came on board in 1963 with the initial funding to develop a relativity gyroscope experiment. Forty-one years later, the satellite was launched into orbit about 400 miles above Earth.
The project was soon beset by problems and disappointment when an unexpected wobble in the gyroscopes changed their orientation and interfered with the data. It took years for a team of scientists to sift through the muddy data and salvage the information they needed.
Despite the setback, Gravity Probe B’s decades of development led to groundbreaking technologies to control environmental disturbances on spacecraft, such as aerodynamic drag, magnetic fields and thermal variations. The mission’s star tracker and gyroscopes were the most precise ever designed and produced.
Played a role in developing GPS
Innovations enabled by GP-B have been used in the Global Positioning System, such as carrier-phase differential GPS, with its precision positioning that can allow an airplane to land unaided. Additional GP-B technologies were applied to NASA’s Cosmic Background Explorer mission, which determined the universe’s background radiation. That measurement is the underpinning of the “big bang theory” and led to the Nobel Prize for NASA’s John Mather.
“The mission results will have a long-term impact on the work of theoretical physicists for years to come,” said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. “Every future challenge to Einstein’s theories of general relativity will have to seek more precise measurements than the remarkable work GP-B accomplished.”
Over the course of its mission, GP-B advanced the frontiers of knowledge and provided a practical training ground for 100 doctoral students and 15 master’s degree candidates at universities across the United States. Over 350 undergraduates and more than four dozen high school students also worked on the project, alongside leading scientists and aerospace engineers from industry and government.
Sally Ride, the first American female astronaut in space, worked on GP-B while studying at Stanford. Another was Nobel Laureate Eric Cornell, who also studied at Stanford.
NASA’s Marshall Space Flight Center in Huntsville, Ala., managed the Gravity Probe-B program for the agency. Lockheed Martin Corporation of Huntsville designed, integrated and tested the space vehicle and some of its major payload components.
===========================================================
Learn a lot more on testing Einstein’s theories here h/t Dr. Leif Svalgaard via email
Leif Svalgaard says:
May 8, 2011 at 1:51 am
“We are seeing a galaxy that now is 40 Gly away.”
I’m going to leave this alone, because the horse is long dead.
“Perhaps you are confusing light years and parsecs….”
Actually, recessional velocity must have been sub-light at that time because it is below the Hubble radius of 13.8 Bly and, otherwise, the light would not have gotten to us. But, the calculation is simple enough. Hubble’s constant is about 71 km/sec/Mpc. A parsec is 3.26 ly. Speed of light is 300e3 km/sec. Recessional velocity is (was) 71*13.2e9/3.26e6/300e3 c = 0.96c.
“The measured redshift is ~10.”
In that case, barring any additional information, I assume the Wiki graph is plotting velocity now versus redshift of a photon emitted then. That’s fine. It’s just a convention. But, I wish they had made it clear in presenting the graph.
Jim Masterson says:
May 8, 2011 at 8:22 am
“I doubt that such a structure could withstand the centrifugal force and would fly apart.”
I think you need to give this some more thought. Centrifugal “force” is mass times centripetal acceleration. How difficult is it to find materials which will stand up to that kind of g-load?
Myrrh says:
May 8, 2011 at 10:39 am
“There is nothing in that diagram that shows Time being warped or that it is even involved. Claiming it is a representation of 4 dimensions is nonsense. It represents a claimed scenario in simple 3D, of the body with mass affecting the space around it.”
It is NOT a representation, it is an analogy. It does not represent anything in 3D. It represents something in 2D which is analogous to the situation in 4D. You are taking this analogy WAY too literally.
“What you’re not dealing with here is that “spacetime” is still unproven.”
It gives us results which are replicable and repeatable in the real world, and allow us to design neat stuff like Doppler radar and GPS systems. If you don’t like it, that’s your personal preference. But, it’s not going to stop the rest of us from exploiting its predictions.
Leif Svalgaard says:
May 8, 2011 at 11:10 am
“Re my: “What is simply not true?”
that the two effects cancel out exactly.
Still can’t find it. Please point it out.
Myrrh says:
May 7, 2011 at 4:20 pm
“Remarkably, these two effects cancel each other for clocks located at sea level anywhere on Earth.”
and this is simply not true.”
The claim in Myrrh’s reference was not anything as general as he thinks or you have accepted. It is making a very narrow claim, which is this: time runs slower at the poles of the Earth than it does at the equator due to the fact that the radius of the Earth is smaller there (GR effect). But, it runs slower at the equator than it does at the poles because of the velocity of a point on the equator is greater than the velocity of a point at either pole (SR effect). It is claimed that the two effects roughly cancel each other out. Maybe so – I have not done the calculation though, and am not endorsing it until I have.
Myrrh says:
May 8, 2011 at 11:11 am
“What I mean by space and time to be “warped” is exactly as it is presented by you, generic, in the diagram which begins this discussion. That is what I am describing and commenting on.”
Stop. Please, stop. It is an analogy which has failed to give you the desired insight. It is not IN ANY WAY a rigorous explanation of what is happening in 4D spacetime.
Bart says:
May 8, 2011 at 11:42 am
Leif Svalgaard says:
May 8, 2011 at 11:10 am
Let me make this a little clearer…
“It is claimed that the two effects roughly cancel each other out over the oblate spheroid of the Earth regardless of latitude. The slower the time from GR, the faster from SR in roughly equal measure and vice versa.
Bart says:
May 8, 2011 at 11:51 am
Bart says:
May 8, 2011 at 11:42 am
Leif Svalgaard says:
May 8, 2011 at 11:10 am
Let me make this even more clear…
The point is that time is roughly uniform in rate over the surface of the Earth. It says nothing about the rate of time on the surface of the Earth versus anywhere else.
I’ll reply to Leif and Bart tomorrow. Meanwhile, for our delectation or consternation depending on one’s view, it’s all relative ain’t it, something I’ve just found while reading this site’s pages:
http://einstein.stanford.edu/SPACETIME/spacetime4.html
As several have mentioned and in several different ways, the experiment’s claim to have proved two of Einstein’s theories has had to be tortured out of the data gathered and even that not done very well..
Why not just admit it? There’s nothing here, after 52 years of experimental data collection, that can’t be explained in bog standard 3D movement of bodies in a fluid, curvature included.
http://einstein.stanford.edu/SPACETIME/spacetime3.html
And doesn’t make any sense elsewhere in science knowledge.
Savin was right istm, what has been happening is that the equations work where they do because they revert back to Newton or other known effects, that is, can be explained otherwise than by the claim that it is this entity ‘spacetime’ being warped by matter as the cause of ‘relativity’ and whenever it is tried to prove that this is alone the cause there is only failure to produce the evidence.
Perhaps an interesting experiment in trying to measure perception, but like the man who mistook his wife for a hat, what then does he make of it when he sees a real hat?
So, Yang was right.
To mods, much appreciated.
“There’s nothing here, after 52 years of experimental data collection, that can’t be explained in bog standard 3D movement of bodies in a fluid, curvature included.”
No, Myrrh, that just isn’t the case. Newtonian mechanics doesn’t explain the bending of light via gravitational lensing. It doesn’t explain the cosmological and gravitational redshifts. It doesn’t explain the precession of the perihelion of Mercury. It doesn’t explain the loss of output energy from binary pulsars. It doesn’t explain the clock trends on satellites and experimental aircraft.
That researchers are looking for chinks in the armor of General Relativity should come as no surprise. But, so far, none have been found. And, it is no reason to throw out all the results which have been confirmed when we can make such good use of them.
It is true that the frontiers are uncertain, and something even better may replace General Relativity as the leading theory of gravity someday. But, if so, it will simply extend General Relativity in the same way General Relativity extends Newtonian mechanics. At worst, all that will change is the interpretations, but not the formulas.
Myrrh:
I am making a comment in hope of clearing a log-jam in the interesting discussion you are having with Lief. My intention is to reduce misunderstanding that is hindering communication, but if it does not then please ignore this post.
At May 8, 2011 at 10:39 am you say in response to a comment from to Leif:
“What you’re not dealing with here is that “spacetime” is still unproven. These things may well happen, I don’t have the time to go into more complicated effects witnessed in our world, but you still haven’t proved that it is your “spacetime” that is doing this, that it even exists, that the method claimed is warping it is even possible!”
OK. But it does not matter if “spacetime is still unproven”. Indeed, it does not matter if spacetime exists other than as a useful concept.
Spacetime is an idea about the nature of the universe, and that idea can be accurately described mathemnatically. The mathematics enable predictions of behaviours in the universe and – to date – every such prediction which could be tested has been shown to be correct. Several of the predictions are counter-intuitive so the findings that they are correct is strong supporting evidence that the idea is correct.
So, the idea of spacetime is the best description of the behaviour of the universe that we have. This does not mean that spacetime exists in reality (although I and many others think it does). However, the concept of spacetime will continue to be used until we obtain a better description of how the universe behaves.
Please note that there is reason to doubt the existence of spacetime: viz. at very small scales the predictions provided by spacetime (i.e. the description of the universe provided by the idea of spacetime) do not apply and the rules of quantum mechanics apply.
In summation, spacetime is a very useful concept as a tool for describing the behaviour of the universe (at large scales), and it is not relevant to its usefulness whether or not spacetime actually exists.
I sincerely hope this helps.
Richard
Myrrh,
Forgive me if I’m wrong, but you seem to perceive the trampoline as a repesentation of the field around the Earth, such that when you envisage a multitude of these you claim they cancel each other out.
But the trampoline is a contrivance by which to imitate the gravitational slope, and is merely a projection of what is taking place on a plane passing through the centre of the Earth. Such a plane coincident with the equator should show some twisting, the effect of drag in the direction of rotation. One difference however, would be that unlike the trampoline above which shows a sharp kink or dragpause, the drag should diminish with the square of the distance and extend as far as the gravitopause, assuming there is such a thing.
Another plane at 90 degrees to the equator will be distorted into a wave shape (by the swirling honey) and thus show a different representation of the effect of drag in the direction of rotation. Likewise, every plane in between will be different, but each will show the drag from its own perspective and none will cancel out.
I hope this helps you not to take the trampoline so literally.
wayne says:
May 6, 2011 at 9:55 pm
“No, I wasn’t speaking of field density but acceleration.”
Well that’s fine if acceleration is what you meant, but it ain’t what you said. viz: “Don’t look at that green-blue mesh and think that is what the real signature of Earth’s gravitational field would actually look like, well, kind of, but not correct. At the center of the Earth there is no gravity field, zero.”
So I would agree with your dimple wrt acceleration, but not for field density which I maintain should be at maximum at the centre of the Earth.
“You think it would be at maximum but I know there is none at the center, in fact, no such field exists at all.”
Weightlessness is not an indication of zero field strength, but rather that forces are balanced out, as with an astronaut in orbit where he is most certainly under the influence of gravity. Gravity is maxed at the centre because mass is maxed at the centre, regardless of whether gravity is real or just a mathematical construct.
Slacko says:
May 8, 2011 at 10:47 pm
Gravity is maxed at the centre because mass is maxed at the centre, regardless of whether gravity is real or just a mathematical construct.
No, gravity is zero at the center, because gravity inside a small sphere [shrink it down to zero size at the center] only depends on the mass inside the sphere and not on the infinite mass outside the sphere. Already Newton knew this. Today this is known as Birkhoff’s theorem because it also holds in General Relativity.
Gravity will not pull you down any further then the centre of the Earth if you could fall that far at this point the gravitational force is balanced if you overshot the centre you would be pulled back.I think that the strength of gravity would be determined by the amount of total mass mostly if you were in the centre of a massive planet you would be crushed flat I think.
don penman says:
May 9, 2011 at 2:26 pm
if you were in the centre of a massive planet you would be crushed flat I think.
If you drilled a tunnel all the way through a massive planet [assuming that you could make the walls strong enough that the tunnel wouldn’t collapse] and dropped down the tunnel, you would find no gravity at the center and not be crushed.
Leif Svalgaard says:
May 8, 2011 at 11.10 am
Re my “Dealing with here is that “spacetime” is still unproven.”
All my links have not had any effect, it seems. Spacetime is one of the best supported fact of all of science.
So, where’s the proof that it exists?
I’ve looked at a lot of pages now. Odd, but no explanation of “spacetime”, no explanation of how “time” is actually warped, actually, zilch. And, I’m beginning to agree with someone who commented above about your responses, that you don’t actually engage in discussing the points. I too find you deflect by passing on to “your links” as if the answer to my question is to be found there, and regardless I’ve said that it isn’t, you keep doing it. Moreover, when I’ve called you on a specific point from your links, you ignore it, or continue your what is now becoming very rude deflection in its own right, but it still comes coupled with your condescending arrogance as you’ve just shown again.
My view, is you don’t know. You’ve probably never thought about it and have nothing to say, or you don’t understand it. Actually, probably the latter, because you so consistently avoid engaging in my actual points.
So come on Leif, show me a real explanation of “spacetime” proven as a fact.
Re my “It represents a claimed scenario in simple 3D, of the body with mass affecting the space around it.
spacetime is curved.
Yeah, yeah.
Re my “What is simply not true?”
that the two effects cancel out exactly.
followed by my: “Still can’t find it. Please point it out.”
So, Leif, you then post the original as here, where I am quoting from a link which looks comprehensive about GPS, originally posted by PaulH above:
Myrrh says:
May 7, 2011 at 4:20 pm
“Remarkably, these two effects cancel each other for clocks located at sea level anywhere on Earth.”
and this is simply not true.
So Leif, the first time around you added a link to a page to prove what you said, that this my quote was not true. You have deflected my requests since then to show me exactly from the page you linked to which supposedly proves that this is not true. You have avoided doing it, and now, you insult me even further by repeating your original statement instead of showing me on the page you linked to, where exactly it proves that what the quote is saying is not true.
Your replies are a joke. Now who was it who noted that here? Ah yes, Alexander Feht on May 5, 2011 at 11:29 pm http://wattsupwiththat.com/2011/05/04/einstein-proven-right-again/#comment-654098
“In many cases, Dr. Svalgaard doesn’t give meaningful answers or explanations. Actual intellectual content of his posts, if you look beyond the obfuscating jargon and painful reiterations of the obvious, is difficult to discern.
Dr. Svalgaard repeats textbook definitions and/or gives you a link to a Wikipedia article that contais a textbook definition – or, if you insist on clarification, pretends to misunderstand your question ..”
I now have ample proof Leif, that Alexander got you down to a t.
And as I wondered, in this particular example here, whether you were confused by the fact that general relativity wasn’t being explained on the link you posted to avoid answering me and by your continuing deliberate avoidance to engage with my asking you explain what you meant, and, with a confusion you showed earlier in this discussion about what speeds up when, I think you don’t know. Like Alexander said. You’re covering this ignorance with some very heavy footwork, tedious statements and deflections to links and avoidance of direct engagement with particular points, and your rudeness runs all the way through it.
So I won’t bother with replying to the rest of your post.
REPLY: “Myrhh” try stepping out from behind the curtain if you want some respect. Leif probably doesn’t want to engage you because you aren’t worth all the time, as your style typically becomes argumentum ad infinitum. I wouldn’t respond much either. I’m really growing tired of moderatingyour thread disruption and insults. It is becoming tedious. For now, you are in the troll bin, all posts get an extra level of inspections, and some like this one, with insults, won’t be posted. clean up your act a bit. Be as upset as you wish, but don’t put it to words. – Anthony
Myrrh says:
May 9, 2011 at 3:22 pm
“Spacetime is one of the best supported fact of all of science.”
So, where’s the proof that it exists?
Anthony is right, it is becoming tedious.
Perhaps a movie would be better for you: http://www.youtube.com/watch?v=AZ6N85lNgHY&feature=related
Bart says:
May 8, 2011 at 4:14 pm
Re my “There’s nothing here, after 52 years of experimental data collection, that can’t be explained in bog standard 3D movement of bodies in a fluid, curvature included.”
No, Myrrh, that just isn’t the case. Newtonian mechanics doesn’t explain the bending of light via gravitational lensing. It doesn’t explain the cosmological and gravitational redshifts. It doesn’t explain the precession of the perihelion of Mercury. It doesn’t explain the loss of output of energy from binary pulsars. It doesn’t explain the clock trends on satellites and experimental aircraft.
As I noted above, Einstein went back to Newton for basics, but I’m not arguing Newton v Einstein. I’m arguing that “spacetime” is just another name for the space surrounding Earth and that, including ‘gravitational lensing’, istm, can be explained by simple 3D bog standard knowledge of bodies in fluids at speed, etc. As for the clocks, they’re mechanical… But seriously, molecules in Air move considerably more slowly under gravity and Air pressure, what’s the difference? That doesn’t mean “Time” has slowed down… ..that someone won’t age as fast in space as they would on the ground, do all the molecules in the body slow down in aging? Or just in efficiency?
Again, you’re saying things that are still not actually proven, redshifts are still under debate and there have been a lot of comments too above which have noted such and rather a lot that have noted this experiment likewise has not actually proven anything. Yet the claim is that is has confirmed two of Einstein’s whatevers. Where?!
And several have noted that this ‘honey’ is just normal space as fluid affected by mass, so for curvature, please, read my golf ball in flight link, and my failed attempts to engage with Leif about boundaries, what’s different about how the mass of the golf ball reacts with the fluid gas Air around it and what these experimenters have actually found that there is this fluid honey around Earth? Only the size.
That researchers are looking for chinks in the armor of General Relativity should come as no surprise. But, so far, none have been found. And, it is no reason to throw out all the results which have been confirmed when we can make such good use of them.
Well, sorry, I’ve read that quite a lot have been found.. But, that some equations work is not what I’m arguing against, I’m arguing that the explanation behind the equations can’t be real fact in our 3D world, that this concept of “Time” in relativity doesn’t make sense, and please, do give me some actual good explanation and verified data that it is actually “Time” that is being warped if you have it. All this can be explained by our normal understanding of states of matter. It’s staring us all in the face that this experiment has shown that the space around us in which the Earth and all the planets move is a FLUID, because it moves like a fluid as do liquids and gases. Not a static/expanding ‘something’ called ‘spacetime’, which so far, have you found all the missing matter yet? no one can explain what it is. And yet the claim is that this is actually including Time itself!
Have you ever felt Time slow down? I have, when I found myself about to crash into another car which decided to overtake the cars in his lane and so coming straight at me down the hill where I was in the overtaking lane doing 70 going up, and the lane to my left was crowded. From the moment I saw the whites of his eyes and realised he had no answer..
I aged faster …
It is true that the frontiers are uncertain, and something even better may replace General Relativity as the leading theory of gravity someday. But, if so, it will simply extend General Relativity in the same wya Gerneral Relativity extends Newtonian mechanics. At worst all that will change is the interpretations, but not the formulas.
Right, and it’s the interpretations I’m looking at. And when I began, in this actual discussion, it was because the concepts behind ‘spacetime’ and the diagram and example of the Earth squashing it and so altering both space and ‘Time’ were never forthcoming whenever I’ve seen them before. This was my first opportunity to actually question anyone on this.
I’m rather pleased with my investigation so far. Thanks for discussing it.
Lief:
I understand your frustration.
It seems to me that Myrrh fails to understand that all scientific descriptions are models. Every scientist knows that any model may be modified or replaced in future. But many non-scientists think that a scientific description is THE WAY IT IS.
The space-time continuum is one of the best models we have. As you have repeatedly said, it is an excellent model in that it both explained existing observations which Newtonian mechanics could not (e.g. perturbation of Mercury’s orbit) and predicted effects that were subsequently discovered (e.g. time dilation in a gravity field). And all attempts to obtain observations which contradict it have failed.
Now the space-time continuum may be THE WAY IT IS or it may not. But so what? It is one of the best models we have, and a scientist is only interested in whether a model is a good and useful description: the space-time continuum is one of the best models we have.
Myrrh’s posts indicate he wants proof that the space-time continuum is THE WAY IT IS, but no scientist can provide such a proof of any model. Hence, I understand both your and his frustrations.
Richard
Richard S Courney says:
May 8, 2011 at 5:43 pm
Thank you for your post, yes it does help.
Several of the predictions are counter-intuitive so the findings that they are correct is strong supporting evidence that the idea is correct.
There’s counter-intuitive and counter-intuitive, I’m still amazed that anyone worked out that the Earth revolves around the Sun. But I can’t see anywhere in any of the explanations that actual Time is taken into real consideration, the descriptions are only of bog standard space, and, as I’ve discovered since joining in the discussion here, that explains it consistent with the knowledge we’ve gained in science about masses and fluids and speeds.
I think, I’m concluding, that all General Relativity re gravity can be explained as our 3D world happening in Time and such things as the clocks slowing is consistent with our now normal understanding of how matter is affected by pressure and gravity. Time itself doesn’t actually change in this just the mechanical slowing down or speeding up relative to gravity and pressure and so on, but also, the speed at which we perceive time can change dramatically. A bat lives and flits about our world as if wholly in our time and mostly it is, but if you listen with bat ears all the sounds we hear at our speed are much slower for a bat, much more drawn out. Time still hasn’t changed, just some things work in different times and so on. What we don’t know is what Time is.
Please note that there is reason to doubt the existence of spacetime: viz. at very small scales the predictions provided by spacetime (i.e. the description of the universe provided by the idea of spacetime) do not apply and the rules of quantum mechanics apply.
I’ve noted, though I haven’t read enough yet of the differences or sure that I understand qm enough to judge anyway, that there’s not the same disjunct between quantum mechanics and what is already known as there is between qm and the spacetime universe. I’ve found an example of what I mean here:
http://www.nhn.ou.edu/~kieran/reuhome/vizqm/2schroeq.htm
“When considering objects as small as electrons, the equivalent to Newton’s Laws is an equation which was originally written down by Erwin Schrodinger. This equation cannot be derived from any funamental law but is based on several well established principles of physics.”
Seems to me that qm is building on what we already know well, a progression in our understanding, and I think that if the fluidity of space was to replace the spacetime concept, that things would fall into place from it in explaining such stuff as curvature and clocks. The right tool for the job?
“
Richard S Courtney says:
May 9, 2011 at 5:23 pm
Myrrh’s posts indicate he wants proof that the space-time continuum is THE WAY IT IS
He is quite right that I do not know THE WAY IT IS. Nobody does. It is an undefined concept. To prove that a rock on the ground exists I give it hard kick. If my big toe hurts I accept that the rock exists and that that is the WAY IT IS. Freely after:
“57. Refutation of Bishop Berkeley
After we came out of the church, we stood talking for some time together of Bishop Berkeley’s ingenious sophistry to prove the nonexistence of matter, and that every thing in the universe is merely ideal. I observed, that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it — “I refute it thus.”
Boswell: Life”
Myrrh says:
May 9, 2011 at 5:24 pm
But I can’t see anywhere in any of the explanations that actual Time is taken into real consideration
What is ‘actual Time’ then? Try to express that. My and any other scientists definition is that time is what a clock shows. If that is not ‘actual’, then what is?
Myrrh says:
May 9, 2011 at 5:24 pm
But I can’t see anywhere in any of the explanations that actual Time is taken into real consideration
Perhaps it will help you to read this: http://en.wikipedia.org/wiki/Time
Slacko says:
May 8, 2011 at 9:46 pm
Forgive me if I’m wrong, but you seem to percieve the trampoline as a representation of the field around the Earth, such that when you envisage a multitude of these you claim they cancel each other out.
I was using it as any example, as the example usually given of this effect of the mass Earth creating gravity by warping spacetime is one of a rubber mat, to explain the diagram above of the warp effect.
So what I was saying is that this distortion at its deepest point, when extrapolated for a 3D figure, creates a continuous boundary layer all the way around, like a shell. So the open side opposite the deepest point of strongest gravity is constrained in some way by this shell – i.e. the distortion is first of all at its deepest point all around, so the effect of actually warping the space is cancelled out – in other words, against what is the Earth distorting in any one direction when it is doing so equally in all directions at the same time? (Assuming for the moment that the “Earth” is like “average” here, a perfectly round sphere.)
There is no distortion. You cannot extrapolate that to 3D reality because the Earth cannot be equally forcing its mass/weight into the space around it at every point to get that effect all around the Earth. It’s simply illogical in our normal everyday 3D reality. You have to show that the Earth is actively forcing its way into this ‘spacetime’ first. If it’s distorting it in one place it cannot be doing so in another.
So, from there I wondered what is does look like if it were ‘equally distorting the space all around it’ and I get the known 3D example of a ball suspended in water. Neither floating nor sinking, just heavy enough to stay in the middle. Now what is interesting in this is that when calculating about such things the force of the water acting on the body is taken into account. This is also missing from the spacetime scenario, at least I haven’t seen anything about it, spacetime appears to be something that can be distorted but not something that has any reality of its own which any medium should have…
Simply taking ‘time’ out of the ‘spacetime’, brings us back to normal reality where things do act on other things, relative to other things.
From there, from the Earth being suspended in some medium, called space, I wondered how gravity was actually working on all these points of distortion of the space around it, which includes how space is forcing its presence onto the Earth as water is doing on a ball suspended in a bath of it, for example, the pressure is equal on all sides. That boundary layer between surfaces, between the surface of the Earth and the edge of space all around it. (The edge being the rubber sheet or the trampoline, both the rubber and trampoline extend in all directions from their edges.)
Thinking of boundaries, I thought then of the boundaries around a moving object in space, such as the golf ball example I gave. It’s a good example, because these boundary layers of an object travelling in space are very well understood, wind tunnel testing and so on. So a golf ball can also have spin, like a tennis ball hit hard and sliced, and how these effect the air they are in are well known. The Earth is exactly like this in the space it is in, travelling fast like the golf ball it will have the same kind of boundary layers around it made out of whatever constitutes the space around Earth.
Immediately around the speeding golf ball all is quite, the Air (Air is a gas; liquids and gases are fluids, in contrast to solids) is still immediately around the golf ball, sticking to it, then comes a boundary layer of slurpy moving Air which as it passes over the golf ball begins whirling and tumbling behind it, above that boundary layer the Air is travelling at great speed past the ball. What happens when spin is added?
So far, an Earth merely with presence in this honey space fluid around it would behave as a ball in a bath (assuming for the moment a closed universe with edges, let’s say it itself is a bubble of Space in some other fluid and all our billions years history are in that bubble and the bath representing that bubble which is our universe), wouldn’t be doing very much at all, suspended as it is in this and we haven’t felt it, not that I know of, bumping into the edge of our universe bubble. So we would have it suspended somewhere in this Space Fluid or bumping into the edges and the Space Fluid exerting its own pressure on it and not a lot happening, except for the fact that it is moving at great speed through it.
Suspended and not moving what is there in its mass that could created gravity, attraction to itself? What happens at the boundary layer of a ball in a bath of water? However, the Earth moving, and spinning is what is said to create the water down the plug hole differences in hemispheres – and thinking of this I wondered if the Earth’s spin is what is attracting stuff to it. Perhaps even pulling in this Space Fluid itself and objects just fall at the speed this happens because they’re in the speed of the Space fluid. Anyway, that’s as far as I’ve got.
I think it is the spin, because if the Earth merely suspended in Space Fluid then it’s not doing anything more than a ball in a bath of water. If only travelling at speed, again, the layer of Space Fluid immediately in contact is still, not a lot happening there to attract stuff to it as ‘gravity’, with the only movement happening in the next boundary layer which is sliding off it and so would be taking stuff past Earth. It must then be the Spin. Earth’s spin is grabbing stuff. That’s what Gravity is. And as its grabbing stuff what it’s really grabbing is the Space Fluid around it and stuff comes in with it.
That it is some kind of fluid medium is the only thing of value from that experiment – and, should be shouted from the rooftops of Science.
Leif – clocks are only one way of measuring time, they do not represent Time. A bat measures time quite differently from us in its hearing, it hears sounds very draaaawn ooouuuttt and sllooowww. It does this even when flying very fast or hanging very still. Perception of time can be different physically as for the bat and for ourselves, is the bat’s clock in this running slow or is ours running fast? But as for the clocks supposedly proving that time in ‘spacetime’ is being warped, they are matter. Matter is affected by gravity and pressure. In our atmosphere which is the gas Air, molecules will travel through it faster the less of it there is, i.e., the higher one goes the less pressure and gravity and so stuff moves more quickly. If it wasn’t for gravity and the resultant air pressure created we wouldn’t hear sounds at all, it takes molecules being constrained by this to give a medium where they are close enough to be moved by sound and to vibrate ‘on the spot’ passing that vibration on. What you, generic, are calling time in ‘spacetime’ and clocks, is only changes in speed.
As someone noted above, ‘they found that the gyroscopes moved a fraction affected by gravity’, and his conclusion, ‘well, duh’.
This experiment isn’t showing any such thing as confirmation of ‘spacetime’, all it’s finding is an extension of our natural world.
But, the Space Fluid is profound, especially as I’ve concluded its capture creates Gravity by the spin of the Earth which explains how bodies of different weights fall at the same speed… Look forward to my Nobel Prix. How much is it worth now?
Or, Earth’s spin plus the immediate still Space Honey around the speeding Earth. Like our Atmosphere pressing down a ton or so per sq foot and we don’t feel it, there could be an intrinsic speed to the pressure of the Space Fluid around the Earth, which would be like then the kind of pressure on a ball from the bath water it is suspended in, on all sides equally. Can we estimate the weight of that still layer of Space Fluid sticking immediately around the Earth from the speed at which things fall in gravity?
Myrrh says:
May 9, 2011 at 4:25 pm
Please do me the courtesy of reading through this thoroughly before responding. I have put significant effort into explaining these things to you, and I’m not going to respond anymore to anything which ignores what I have already explained. Besides, if you stick around to the end, you may find I’ve thrown you a bone or two.
“That doesn’t mean “Time” has slowed down… ..that someone won’t age as fast in space as they would on the ground, do all the molecules in the body slow down in aging? Or just in efficiency?”
Maybe it would help you to consider something more elementary. Time is also affected by relative motion (Special Relativity). There can be no doubt of that effect. It is confirmed every single day in atom smashers at CERN, Fermilab, and other places, and in more mundane applications, such as the Doppler radar images you see on the weather report every night, and the Doppler radar your local police use to patrol your roads. Special Relativity DOES extend all the way down to the quantum world, and explains, among other commonly observed effects, the existence of antimatter. Antimatter, in fact, was “discovered” purely by the mathematics of Special Relativity married to classical quantum theory, years before it was actually observed.
The Doppler shift, by itself, confirms Special Relativity in all its essentials. You may not be aware, but the Doppler shift for sound, which you hear every time a vehicle goes rumbling by, rising in pitch as it approaches, and decreasing as it recedes, takes on very different forms depending on whether you are moving toward or away from the source, or whether the source is moving toward or away from you. Not so, the Doppler shift for light, which takes the same form regardless. Time and space are inherent in the way the formula for the shift is derived for both sound, and for light. Therefore, the ONLY way for that to be so is if both time and distance change due to motion or, equivalently, if light propagates at the same speed regardless of the speed of the observer.
So, we know these things. They have been proven. There can be no argument with this, no wiggle room at all. Special Relativity is fact, and only someone ignorant of the facts would argue otherwise. From that foundation, it is not much of a stretch to conclude that gravity acts to distort time. Indeed, it is absolutely necessary, if inertial and gravitational mass are equal, and exquisitely precise experiments have never measured any difference outside experimental error limits (to understand the difference between inertial and gravitational mass, try google or wikipedia).
“Again, you’re saying things that are still not actually proven, redshifts are still under debate…”
Redshift is a generic term. Generally, we speak of three kinds: Doppler, gravitational, and cosmological. Doppler emerges from relative motion, as I have described above. Doppler redshift is completely proven – enough said. Gravitational redshift is due to electromagnetic radiation passing through a gravitational field. Again, it is not such a tall leap from Doppler redshift to gravitational redshift. It has also been proven by any reasonable standard, by radar signals bounced off of our neighboring planets, among other experiments.
Cosmological redshift is less of a slam dunk. It is, at least, plausible given the other two. And, it fits with our observations. Everywhere we look in the night sky, almost every object is redshifted from where it ought to be. If it is due to Doppler shift, then that means almost everything is moving away from us in particular, and we are effectively at the center of the universe. Given that messiness with Copernicus and Galileo some years ago, which moved us away from the center of Creation, scientists are understandably reluctant to indulge their hubris in reestablishing our existence there. You must admit, barring God himself’s desire for us to be there (and, claiming to know the mind of God is not a little blasphemous), it is exceedingly unlikely that we would be. The only other plausible explanation we have yet conceived is that everything in the universe is moving away from everything else, and this means the entire fabric of the universe is stretching. And, fortuitously or not, it just so happens that the General Theory of Relativity predicts just such a universe is physically realizable. And, so far, it all fits together like the pieces of a jigsaw puzzle. So, either it is right, or it is a series of amazing coincidences piled one on top of another.
So, hopefully to end this discussion for now, I will say to you this: Special Relativity is a fact. Warpage of space and time is a fact. General Relativity is, at the very least, a very good description of gravity which will never be overthrown, just as Newton’s mechanics have never been overthrown, despite what some people appear to believe, but merely extended. Cosmology based on General Relativity is… plausible, and so far, all the evidence appears consistent with it, enough so that there is every reason to continue exploring its implications – I think we may never know for sure unless we find some loophole which allows us to actually reach these far away places and explore them firsthand.