Problems with G (split from history of astronomy)

[madmac]

Klaynos.

There is lots of stuff out there re the problem with G.

Final Demystifycation of the Gravitational Constant Variation -- is one.

Do u know about the borehole anomaly??

[Klaynos]

Klaynos.

There is lots of stuff out there re the problem with G.

Final Demystifycation of the Gravitational Constant Variation -- is one.

Do u know about the borehole anomaly??

Cite properly. If you can't do links do title, author, date and publisher.

 

We have measured G to a very high precision now. The Cavendish experiments were the first but we've added to it. They're relatively accessible hence I gave them as the example.

[Bender]

I wouldn't call three digits "very high precision".

[madmac]

Bender.

Make that 2 digits.

Some sources report plus 0.7%, some minus 0.2%.

A borehole analysis gave plus 1%.

A Russian source found a curious variation of up to 0.7% over time.

 

Prof Reg Cahill has measured turbulence of up to 20% (of speed or something) in what he calls Dynamic Space. And says that measurements of G (not by him) produce values that differ by nearly 40 times their error estimates. All of Cahill's 40 or so papers on Process Physics can be found in various sites on google, including Flinders University, & Mountain Man Graphics, & Physics arXiv. The one i was reading just now was Gravity as Quantum Foam Inflow (2003).

 

Cahill says that Newton's inverse square law is only applicable for spherical symmetry & is therefor inapplicable to say spiral galaxies & Cavendish type experiments. Not forgetting the wild swings due to turbulence.

Edited February 5, 2017 by madmac

[John Cuthber]

I wouldn't call three digits "very high precision".

I wouldn't call it relevant since G is known to 4 digits- not great precision, but they are working on it.

 

Madmac seems to be including the worst estimates he can find ; is there some reason why he's avoiding the better ones?

I mean what's the point of saying "A Russian source found a curious variation of up to 0.7% over time."?

We have grandfather clocks that are good enough to disprove that idea.

[madmac]

Einstein specifically banned grandfather clocks in relation to SR & GR, because they were based on a pendulum, which is a part of Earth's frame ( or something, cant remember).

And re pendulums, Allais has some concerns also .

Edited February 5, 2017 by madmac

[swansont]

Einstein specifically banned grandfather clocks in relation to SR & GR, because they were based on a pendulum, which is a part of Earth's frame ( or something, cant remember).

And re pendulums, Allais has some concerns also .

 

 

!

Moderator Note

The time for vague rebuttals is over, if you want threads to remain open. You need to cite specific examples (full citations) and also explain why nobody seems to be able to reproduce these results. It's not enough to point to a single experiment when it disagrees with dozens of others. You exclude the outlier. Not the other way around.

[Strange]

Einstein specifically banned grandfather clocks in relation to SR & GR, because they were based on a pendulum, which is a part of Earth's frame ( or something, cant remember).

And re pendulums, Allais has some concerns also .

 

 

There is always a future for you in agriculture with all this experience of cherry picking ...

[madmac]

Ok i found it. In Chapter 5 of On the Electrodynamics of Moving Bodies by A. Einstein (June 30, 1905)(English version), Alby says that a moving clock will be slower than a clock at rest, & Alby says.....

 

"Thence we conclude that a balance-clock (7) at the equator must go more slowly, by a very small amount, than a precisely similar clock situated at one of the poles under otherwise identical conditions".

 

The note (not sure if this is Alby's or the Editor's) at the bottom of the page says.....

 

"(7) Not a pendulum-clock, which is physically a system to which the Earth belongs. This case had to be excluded".

 

Hencely i couldn't resist the urge to point this out to John Cuthber who had said that Grandfather clocks could be used to find G to better than 2 places (digits). However it isn't clear just how a Grandfather clock could be so used.

 

Re my mention of Allais having some concerns re using pendulums (for timing, or for finding G), i would be surprised if everyone here hadn't heard of the Allais Effect, ie the anomalous behaviour of pendulums related to gravity during eclipses.

 

Strange.

I don't see how i am cherry picking when i point out something that Einstein wrote or said. And anyhow it was only in relation to an assertion peripheral to finding G (ie re Grandfather clocks). Unless u mean my reference to 0.7% & 0.2% & 1.0% & 0.7% & 20% & 40 & 40.

[Strange]

I don't see how i am cherry picking when i point out something that Einstein wrote or said.

 

 

That is not an example of cherry picking. It is an example of you citing irrelevant facts (presumably in order to further demonstrate that you don't know what you are talking about).

 

In other words, as this is the Speculations forum and it is up to you to show, in suitable mathematical detail, that the note about pendulum clocks is relevant to the measurement of G. After all, the paper it comes from does not mention gravity at all. (And you can't claim "well Einstein said it so it must be relevant").

 

You could start with the equation for the period of a pendulum and work from there.

[madmac]

Strange.

When John Cuthber made some claims in post#5 u didn't ask for citations & equations etc, especially re the claim re how a Grandfather clock could disprove the idea that G can vary by 0.7% over time. And u didn't point out to John Cuthber that it wasn't what he called an idea (by the Russians), it was the result of an experiment.

 

But when i mentioned some doubts about using pendulums, in particular Einstein's concerns re using a pendulum clock re SR & GR, & that Allais had some concerns re pendulums re gravity, & then i in post#9 provided details, u now demand that i supply equations identifying the physics behind my doubts & how they impinge on John Cuthber's claims.

 

It appears that i am not entitled to raise such matters unless i provide some sort of proof of the underlying physics. Whereas Einstein apparently didn't have to bother when he raised it first (in his 1905 paper). And Allais spent much of his life looking for the cause of the Allais Effect (& got a Nobel), but now it falls on me to find it & define it with equations (even though i suspect that he didn't provide the equations before he got his Nobel). And whereas John Cuthber didn't explain his claim, i nonetheless have to read his mind, & then i have to provide the physics & equations behind my doubts.

 

Well, i am glad that u did, because it lead me to read a few more articles (that i wouldn't have), which i enjoyed, & after all that is the reason i am here on this forum.

Edited February 6, 2017 by madmac

[Strange]

I didn't challenge John because he's referencing well known physics that is obviously correct.

 

On the other hand you aren't able to justify your claim that this note by Einstein is relevant.

[swansont]

 

 

It appears that i am not entitled to raise such matters unless i provide some sort of proof of the underlying physics.

 

 

!

Moderator Note

 

Yes, precisely. If you make claims contrary to mainstream (i.e. well-established) physics, you had better have something to back it up.

 

On the other hand, if someone makes a claim that can be derived (in this case, in just a few steps) by anyone who has passed first-semester physics, it's really not required.

 

[studiot]

To move this thread forward let note that it is a spin-off from a history thread.

 

So to look back at the history of gravitational measurements I note that from Kepler and Newton to the 1930s the main thrust was to determine big G, the universal constant.

 

Here is a table from Newman and Searle (1957 edition) : The General Properties of Matter : showing the state of knowledge at the end of that lengthy period.

 

 

Between about 1880 and 1930 another g, little g, was coming to prominence as the science of Geodesy matured.

It can be seen from the table that D, the average density of the Earth was also becoming considered when the last (Heyl) measurement was listed and that now new information was added on G in the next nearly 30 years.

Newman and Searle also give an account of the detailed study of the factors that might be able to affect the value of G, in the latter part of that period.

 

Good quality gravity measurements are not cheap undertakings so I surmise funding considerations played a part

Geophysical exploration by gravimetric surveying was becoming possible so the impetus moved from big G to little g.

For instance Clark at the NPL obtained an accuracy of 2 parts in 10^-8 in 1940.

The measurement of little g does not suffer the same objections to

 

 

I am not an astronomer so I will leave it to a real one to tell us what is accurate enough for astro/cosmological purposes.

[madmac]

Strange.

My reference to Einstein's concerns re pendulum clocks was as i said related to SR & GR & my meaning there was primarily re reliability re measurement of time (but in my own mind i also realised that there might be other gravitational implications), which i suspected might not be known to all around this forum which is why i pointed it out, all of which could only be generalisations because i didn't know & indeed still don't know what John Cuthber's statement re Grandfather clocks meant.

 

In my googling i didn't see any mention of pendulum clocks ever being used to find G. They were used to find g. And there was mention of them being used to find changes in g, which could be related to possible changes in G, which is not the same thing as putting a number to G.

 

Einstein's writing (not clear if him or Editor) that one needs to use a balance-clock is understandable because these use pure inertia rather than a gravity-inertia effect. Anyhow in future i had better quote someone who has won 2 or preferably 3 Nobels else i will be savagely attacked.

 

studio.

Re accuracy for astro purposes, big G is almost irrelevant, what is relevant for trajectories & orbits is the product(s) G*m, which is known to umpteen digits.

 

Which brings me back again to statements re G being measured to almost 8 digits, i don't understand how this can be reconciled with other articles pointing out discrepancies, which range from plus 0.7% to minus 0.2%, & in particular a ref to Russians finding a drift of 0.7% (i must find details).

 

None of this makes sense. Students should also google borehole anomaly, & the Allais Effect (not the economics one).

I had a lot of fun years ago googling the Tamarack Mine mystery. Its a sort of gravitational who-done-it.

Edited February 6, 2017 by madmac

[Strange]

Strange.

My reference to Einstein's concerns re pendulum clocks was as i said related to SR & GR & my meaning there was primarily re reliability re measurement of time (but in my own mind i also realised that there might be other gravitational implications), which i suspected might not be known to all around this forum which is why i pointed it out, all of which could only be generalisations because i didn't know & indeed still don't know what John Cuthber's statement re Grandfather clocks meant.

 

 

So the fact is that you don't know what determines the period of a pendulum (Google could make up for your lack of education here).

 

This means that you end up citing citing a completely unrelated effect (purely related to special relativity, not general relativity, not gravity and not G) because you mistakenly think it must be related.

 

I struggle to see why anyone should take you seriously when you demonstrate this level of ignorance. I don't even understand why you take yourself seriously!

 

 

 

Anyhow in future i had better quote someone who has won 2 or preferably 3 Nobels else i will be savagely attacked.

 

You totally miss the point. It is not about quoting authorities, it is about understanding the subject and providing rational fact-based arguments. You need to cite relevant evidence and explain, in appropriate detail, why it supports your argument.

 

If you cannot explain why the comment about pendulums is relevant then please withdraw your claim that it is a counter-argument to John's point.

[studiot]

 

 

studio.

Re accuracy for astro purposes, big G is almost irrelevant, what is relevant for trajectories & orbits is the product(s) G*m, which is known to umpteen digits.

 

Which brings me back again to statements re G being measured to almost 8 digits, i don't understand how this can be reconciled with other articles pointing out discrepancies, which range from plus 0.7% to minus 0.2%, & in particular a ref to Russians finding a drift of 0.7% (i must find details).

 

None of this makes sense. Students should also google borehole anomaly, & the Allais Effect (not the economics one).

I had a lot of fun years ago googling the Tamarack Mine mystery. Its a sort of gravitational who-done-it.

 

I am not an expert in astro work, although I have carried out both gravimetric and astro surveys.

 

Thus I asked a real expert.

 

Are you such an expert ?

 

If not, why did you presume to lecture me as though you were?

 

It is fairly obvious to anyone who has done gravimetric work why swinging pendulum clocks are fine for measuring little g, but inappropriate for measuring big G.

It is also obvious to anyone who has ever set up or moved a grandfather clock.

 

If you don't know the answer to this, why don't you simply ask?

I'm sure Strange is bursting to tell you.

[Strange]

It is fairly obvious to anyone who has done gravimetric work why swinging pendulum clocks are fine for measuring little g, but inappropriate for measuring big G.

 

 

Note that John's point was not about using a pendulum to measure G but about constraining the variation in G. (Of course, it is entirely possible that the radius and/or mass of the Earth varies when G changes in order to keep pendulums swinging at the same rate ...)

[madmac]

Strange. studio.

I see no need to change even one word of my earlier jottings.

Almost all of what i say is based on stuff that i have read. In many instances i don't fully understand it, so i need to be careful, & use appropriate wording. Certainly i am not an expert of any sort, & my wording should reflect that. But i think that nonetheless i know enough to see through bad science (ie some of the mainstream stuff).

 

But i would be happy to know what John Cuthber thought of my comments (re his Grandfather clocks, & re pendulums etc).

And i would be happy to know whether Astro experts agree with what i said re G*m being crucial (ie moreso than G & m individually).

Edited February 6, 2017 by madmac

[Strange]

Please explain why the "Note 7" that you quote is relevant to a pendulum demonstrating the stability of G.

 

Or, at least admit you don't understand what John said and that you just grabbed a random statement about pendulums that may have nothing to do with it. Then you have to drop the claim as being nonsense.

[madmac]

Strange.

No, when i wrote that i hadn't given any thought to whether a pendulum is ok for demonstrating the stability of G.

I suspected that Note#7 possibly had to do with Einstein's (or the Editor's) misgivings re whether a pendulum is ok for measuring time.

But, if u think about it, if a pendulum cannot be trusted to measure time, ie g, then it cannot be trusted to measure the stability of G.

But, having said that, any drift in the pendulum's beat could be either due to drift in G (a real effect), or it could be due to some non-related effect (bad timing) feared by Einstein (or Editor).

 

No, i hadn't grabbed a random statement (by a Nobel Prize recipient)(do Nobel Laureates make random statements?) & i didn't drop it later.

 

I stand by every word i have written on this forum, here & elsewhere. However, if anyone here should happen to show my errors, or give me some new information (which they have), then i will be happy.

I have seen some new info & some new links here that i appreciate & were interesting, but none have in any way made me change one iota of my beliefs in aether theory. And it appears vice versa, unfortunately.

If someone has a false idea, then that is one thing (no big deal), but if that someone has had the truth explained but yet adheres to falsehood then that is less forgivable. Yes, it works both ways, but the truth might surface sooner than u think.

[swansont]

 

But, if u think about it, if a pendulum cannot be trusted to measure time, ie g, then it cannot be trusted to measure the stability of G.

 

 

 

!

Moderator Note

If you keep ignoring the requests that your claims need to be supported, this will not end well. IOW, explain they physics behind this, don't just assert it.

[Strange]

I am quite sure that Einstein (who knew some basic physics) had no doubt at all about a pendulum's suitability for measuring time.

 

But feel free to use some science to show otherwise...

[madmac]

swansont re your post#22.

In which u ask me to explain the physics behind my statement that if a pendulum cannot be trusted to measure time, ie g, then it cannot be trusted to measure the stability of G.

It is well known that a pendulum might change its beat if moved, ie due to a change in g due to position or altitude. But, if not moved, the beat might also change due to temperature or air pressure or vibration. Bearing in mind that we are talking mainly about a Grandfather clock here.

 

Which reminds me that when John Cuthber made his statement that "we have Grandfather clocks that are good enough to disprove that idea" (regarding my statement that Russians found a curious change in G of 0.7% over time), no-one asked him to explain the physics. That doesn't bother me much, what bothers me more is that no-one pointed out the lack of logic that any fresh measurements anywhere with any sort of apparatus could possibly disprove that the Russians did actually measure a 0.7% change at a particular place at a particular time.

 

Nextly, there doesn't appear to be any reference on Google that a pendulum has ever been used to measure G. Cavendish used a torsion apparatus in say 1790, & he was the first, despite good pendulums being around since say 1690. Perhaps a pendulum can be used to measure G, armed with a good equation for that pendulum, & using Newton's inverse square equation for gravity, so why hasn't it ever been done (or has it?).

 

It seems to me that a pendulum can be used to measure a change in g at any one location, & hencely a change in G, in which case a Grandfather clock could be used, but u would need a balance-clock (or a non-pendulum clock of some other sort) to measure true period (time).

Strange.

If u are correct that Einstein had no doubts about a pendulum's suitability for measuring time, then it must have been the Editor who authored Note 7 in Einstein's book (see earlier postings). Possibly the Editor of the English version (1920 here).

 

One little problem, Einstein said (somewhere??) that a clock at a low altitude was slower than a clock at a higher altitude. But, i reckon that a pendulum clock beats faster at a lower altitude.

[Strange]

Which reminds me that when John Cuthber made his statement that "we have Grandfather clocks that are good enough to disprove that idea" (regarding my statement that Russians found a curious change in G of 0.7% over time), no-one asked him to explain the physics.

 

Because it is obvious. Perhaps you can show, in mathematical detail, why you think he is wrong?

 

That doesn't bother me much, what bothers me more is that no-one pointed out the lack of logic that any fresh measurements anywhere with any sort of apparatus could possibly disprove that the Russians did actually measure a 0.7% change at a particular place at a particular time.

 

So your argument seems to be that G is stable everywhere, and at all times, when there is a grandfather clock present. But it varies if there are unreliable Russian scientists present. Very logical.

 

If u are correct that Einstein had no doubts about a pendulum's suitability for measuring time, then it must have been the Editor who authored Note 7 in Einstein's book (see earlier postings). Possibly the Editor of the English version (1920 here).

 

I think a more likely explanation is that it was written by Einstein but that you don't have a clue what it means.

 

One little problem, Einstein said (somewhere??) that a clock at a low altitude was slower than a clock at a higher altitude. But, i reckon that a pendulum clock beats faster at a lower altitude.

The change in the period of a pendulum has nothing to do with GR (it is a straightforward mechanical thing). If you want to take GR into account, as well, then the equation for the period of a pendulum is slightly more complicated.