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Author Topic:   What happens if Einstein was wrong ???
RingoKid
Inactive Member


Message 1 of 15 (107050)
05-10-2004 7:48 AM


I don't know enough about it but if Gravity probe B (GP-B) proves certain predictions concerning General Relativity were a figment of Einstein's fertile imagination, then...
...it would probably lose the great man some cred, put a lot of clever people out of a job and make some people's life work irrelevant but what does it mean for the average man in the street and what are some of the far reaching implications stated in the following excerpt from the GP-B website???
What is GP-B?
Gravity Probe B is the relativity gyroscope experiment being developed by NASA and Stanford University to test two extraordinary, unverified predictions of Albert Einstein's general theory of relativity.
The experiment will check, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth satellite orbiting at 400-mile altitude directly over the poles. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are warped by the presence of the Earth, and, more profoundly, how the Earth's rotation drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe.
(quoted from Gravity Probe B: Testing Einstein's Universe)
This message has been edited by AdminSylas, 05-10-2004 10:27 PM

Replies to this message:
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AdminSylas
Inactive Member


Message 4 of 15 (107291)
05-10-2004 11:30 PM


Quoted text indented. Minor spelling errors fixed. Thread moved here from the Proposed New Topics forum.
This message has been edited by AdminSylas, 05-10-2004 10:31 PM

  
Darwin Storm
Inactive Member


Message 5 of 15 (107319)
05-11-2004 1:56 AM
Reply to: Message 1 by RingoKid
05-10-2004 7:48 AM


The purpose of the gravity probe is to test one particular predicition of realitivity. This predicition is that a rotating mass will drag space-time around with it. The effect is extremely weak for a body like the earth, but with the current probe, they are estimating that a year in orbit, with a particular orientation, should detect this effect if it exists.
So far, realitivity has show that both space and time are affected by gravity, and the theory has solid grounding. If this experiment does fail to show the effect, then there would have to be a reconsideration of GR.

This message is a reply to:
 Message 1 by RingoKid, posted 05-10-2004 7:48 AM RingoKid has not replied

  
Sylas
Member (Idle past 5261 days)
Posts: 766
From: Newcastle, Australia
Joined: 11-17-2002


Message 6 of 15 (107354)
05-11-2004 4:23 AM
Reply to: Message 1 by RingoKid
05-10-2004 7:48 AM


RingoKid writes:
...if Gravity probe B (GP-B) proves certain predictions concerning General Relativity were a figment of Einstein's fertile imagination, then...
...it would probably lose the great man some cred, put a lot of clever people out of a job and make some people's life work irrelevant but what does it mean for the average man in the street and what are some of the far reaching implications stated in the following excerpt from the GP-B website???
Einstein's credibility is secure, and will not be affected by the progress in science taking us beyond what he proposed. Science, by its very nature, continues to progress; and the contributions of the past, of geniuses like Leonardo Da Vinci, and Isaac Newton, and Albert Einstein, will continue to be celebrated, honoured and used; even if those contributions turn out to be subsumed or superseded in subsequent developments.
Clever people are not put out of a job by new discoveries. Their jobs become more important; not less. The job of a scientist or engineer is not predicated on the knowledge of the day; it is expected that a professional will be able to keep up with new developments. The experts in old theories are the very ones who are best positioned to grasp and appreciate and apply new knowledge that replaces those old theories. Someone who has no grasp of Einstein's work is at a real handicap in dealing with further extensions or replacements or refinements.
The life work of a scientist is rarely made completely irrelevant by new developments. It can happen; but usually this is when a scientist is pursuing new ideas that don't pan out. The people whose work is most likely to become "irrelevant" are those who are actively proposing a specific new idea to replace Einstein's models. It is more common for major new ideas to turn out to be incorrect than for them to become established as the new foundation for physics. However, this is not "irrelevant"; it is essential to how science works. An idea proposed and rejected is still useful basic scientific research, even if nothing comes of it at all. Rejection sometimes involves finding useful new data, which can still be used by others in other contexts; but even if the only result is "Well, that idea was wrong"; this is still useful and relevant research.
The impact for the man-in-the-street will be pretty much nothing, in the short term, unless they are interested in physics or cosmology. There is a chance of new possibilities for applied knowledge with any new advances in physics; but this is not really something we can predict.
On the other hand, simply solving the problems of building and launching the probe is a major exercise in engineering research and development. There is a definite potential for spin-off applications which may be useful to people who have no idea where they originated. This is described in a page at the site you reference: Spin-off Technology from Gravity Probe B.
The impact on cosmology, for those who are fascinated with learning as much about the universe as we can manage, could turn out to be profound.
Finally (and not wanting to be a wet blanket, but this has to be said):
The most likely consequence, in my opinion, is strong confirmation of Einstein's relativity and the further cementing of this as a pivotal and reliable scientific basis for research in theoretical cosmology.
But let's wait and see. Any new test has potential for surprises.
Cheers -- Sylas
This message has been edited by Sylas, 05-12-2004 02:11 AM

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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 7 of 15 (107427)
05-11-2004 10:47 AM
Reply to: Message 1 by RingoKid
05-10-2004 7:48 AM


If you asked any Scientist what was the Greatest Contribution he could make.
he would say, "Find something that Invalidates or Falsifies one of our basic theories."
That is how advances are made.

Aslan is not a Tame Lion

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Darwin Storm
Inactive Member


Message 8 of 15 (107660)
05-12-2004 2:46 AM
Reply to: Message 6 by Sylas
05-11-2004 4:23 AM


IF I remember correctly, this experiment has been on the drawing boards for almost 50 years.

This message is a reply to:
 Message 6 by Sylas, posted 05-11-2004 4:23 AM Sylas has replied

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Sylas
Member (Idle past 5261 days)
Posts: 766
From: Newcastle, Australia
Joined: 11-17-2002


Message 9 of 15 (107663)
05-12-2004 3:23 AM
Reply to: Message 8 by Darwin Storm
05-12-2004 2:46 AM


Darwin Storm writes:
IF I remember correctly, this experiment has been on the drawing boards for almost 50 years.
Yes... according to Page 3 of "the story of gp-b":
In 1918, two years after Einstein formulated general relativity, W. Lense and H. Thirring calculated that according to the theory a rotating massive body should slowly drag space and time around with it!
Startling and far-reaching as Lense & Thirring's discovery was, any verification of frame-dragging seemed hopeless. Nothing happened until 1959 when Leonard Schiff of Stanford University (and independently George Pugh of the Defense Department) considered orbiting gyroscopes. On Schiff's calculations a gyroscope in polar orbit at 400 miles should turn with the Earth through an angle amounting after one year to 42 milliarc-seconds.
This vitally important frame-dragging effect has never been seen. Gravity Probe B will measure it to a precision of 1% or better.
The rest of the linked pages all make up a really fascinating introduction to this experiement.
Cheers -- Sylas

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Loudmouth
Inactive Member


Message 10 of 15 (107734)
05-12-2004 3:48 PM
Reply to: Message 1 by RingoKid
05-10-2004 7:48 AM


quote:
...it would probably lose the great man some cred, put a lot of clever people out of a job and make some people's life work irrelevant but what does it mean for the average man in the street and what are some of the far reaching implications stated in the following excerpt from the GP-B website???
Einsteins cred is already high, since NASA is spending millions of dollars to falsify/support his theory. Not many physicists can claim this. I would bet my bottom dollar that most scientists wouldn't care if their work was made irrelevant by this probe. Instead, they would be excited to be the first one to come up with the new, more precise theory to replace one of the greatest icons in physics. Besides a bruised ego, scientists see the importance of theories being proved wrong, since the new theory will probably be closer to what is happening in the natural world.

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usncahill
Inactive Member


Message 11 of 15 (109535)
05-20-2004 10:15 PM
Reply to: Message 9 by Sylas
05-12-2004 3:23 AM


This space-time warping effect is kind of hard for me to grasp when applied to this experiment. I don't understand how the probe can measure a characteristic of Earth's gravity with gyroscopes since the experiment starts in the Earth's gravitational field (The gyros are already under the Earth's influence before the experiment begins). I have a moderate hold on the general ideas of relativity and mass' 'warping' of space-time. Can someone explain it better?

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Eta_Carinae
Member (Idle past 4375 days)
Posts: 547
From: US
Joined: 11-15-2003


Message 12 of 15 (109593)
05-21-2004 1:04 AM
Reply to: Message 11 by usncahill
05-20-2004 10:15 PM


Hint:
free fall!

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Sylas
Member (Idle past 5261 days)
Posts: 766
From: Newcastle, Australia
Joined: 11-17-2002


Message 13 of 15 (109600)
05-21-2004 3:29 AM
Reply to: Message 12 by Eta_Carinae
05-21-2004 1:04 AM


Re: Hint:
Hi Eta... I don't understand your hint; and I don't know enough relativity to answer the question with confidence. But I'll take a stab at it. Any comment from you explaining what I get right, and what I get wrong, would be much appreciated.
Here is my attempt.
An object in orbit is in freefall. In conventional Newtonian physics, the orbit of a satellite around a large sphere, like the Earth, is dependent only on their masses. It makes no difference whether or not the large massive sphere of the Earth is spinning; the orbit of the satellite remains the same.
In relativity, this is no longer true. The rotation of the Earth actually drags space along with it, in a sense, and this has an effect also on the orbitting satellite.
Gyroscopes on board the satellite will remain pointing in a fixed direction in space; but if space itself is being dragged along by the spin of the Earth, then the gyroscope will move in the same way. The end result is that it ends up pointing at different regions of the sky after a length of time. The effect is slight, but should be detectable in the new probe... if the effect exists as predicted.
Now I think some of that is on the right track, but I am not sure. I'll bet it could be explained much better. Could you consider this my astrophysics assignment, and mark it for me?
Thanks -- Sylas

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RingoKid
Inactive Member


Message 14 of 15 (109620)
05-21-2004 6:19 AM
Reply to: Message 12 by Eta_Carinae
05-21-2004 1:04 AM


Re: Hint:
free fall as in one of those planes that take a sudden dive so that the people in it and the observer appear to counter the effect of gravity so GP-b with it's suspended gyro's in effect has the characteristics of zero gravity and thus is able to make measurements of the warp effects on space time by a mass object without factoring in the effects of gravity...
...kinda like taking measurements in a plane dive that keeps diving
I am so out of my league here but you should see me when i care. I look exactly the same, just words on a screen

This message is a reply to:
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mogur
Inactive Member


Message 15 of 15 (109712)
05-21-2004 3:53 PM
Reply to: Message 13 by Sylas
05-21-2004 3:29 AM


Re: Hint:
Very nicely explained, Sylas. Austrian physicists Joseph Lense and Hans Thirring derived the frame-dragging effect using general relativity in 1918. Known as the Lense-Thirring effect (also called gravitomagnetism), it is like spinning a huge ball bearing in a tub of motor oil, to greatly exaggerate its effect. Some of the oil will be pulled, or twisted, along with the spin of the ball-bearing, slightly affecting the much more pronounced effects of Newtonian gravity, by a factor of 10 million, and relativistic space-time fabric warping, known as the geodetic effect, by a factor of 100. Since these two relativistic effects are manifested at right angles to each other, they can be independantly verified.
An onboard optical telescope will lock onto a guide star, but its unpredictable stellar drift would swamp out the desired results, so a guide star was chosen that is very bright in microwave frequencies. This allows ground based, very-long-baseline interferometry to correct for this drift by comparing it to very distant quasars.
These effects have already been observed by astronomers non-localy, and at least two nearby direct measurements have been observed, so don't get excited about upsetting Einstein's apple (pun intended) cart. These will be extremely refined measurements that will probably give us a much better insight into relativistic mechanics.
Edited for minor typos.
This message has been edited by mogur, 05-21-2004 05:52 PM

This message is a reply to:
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