Offline SteelyBob

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Re: Cavendish experiment
« Reply #80 on: May 03, 2021, 09:37:50 PM »
I'm just interested in Lackey's answer because he has spent the last couple of pages saying that if you can't explain the mechanism behind gravity then that shows that gravity is a load of nonsense. But things demonstrably fall. So I'm interested to know what he thinks causes that to happen and whether he can explain the mechanism behind it. His failure to respond is pretty telling.

Indeed. I'd also add that I asked him (her?) several pages back precisely what observation or what aspect of our physical world is at odds with the consensus view on gravity. The only answer we've had since then is an appeal to authority from 1693, which he completely failed to understand and continues to misrepresent, no matter how many times people point that Newton was, in fact, rather keen on the whole gravity idea. This is taking argument fallacies to a whole new level - when appealing to authority, most wayward debaters at least choose an authority that supports their argument.

So, to summarise the case against thus far, we have:

- the fact that measurements of the gravitational constant are tricky to do and only accurate to 3-4 sig figs. Therefore, earth is flat.
- Isaac Newton didn't think that gravity could transmit across a vacuum. Therefore, earth is flat.
- the science around the precise mechanism for gravity is still subject to debate and development. Therefore, earth is flat
- water doesn't stick to balls, therefore earth is flat

Have I summed that up fairly enough?

Still waiting for an observation of our physical world that contradicts the consensus view on gravity. Also still waiting for the answer to my question on whether we all at least agree that, if the earth was a globe and gravity existed, then water would stick to it just fine.

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Offline Tom Bishop

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Re: Cavendish experiment
« Reply #81 on: May 03, 2021, 10:09:19 PM »
The same is true of gravity. It has been measured. Cavendish measured it. Lots of people have measured it and they are with 0.15% of each other for the gravitational constant. Why do you need a mechanism before you acknowledge that something is there?

The effect of gravity is much smaller than that range. The 0.15% deviation is dominated by effects which are not gravity. See this section: https://wiki.tfes.org/Cavendish_Experiment#A_Small_Effect

Since the noise highly dominates the effect, how do you know that the effect is actually being measured?

Offline SteelyBob

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Re: Cavendish experiment
« Reply #82 on: May 03, 2021, 10:18:27 PM »

The effect of gravity is much smaller than that range. The 0.15% deviation is dominated by effects which are not gravity. See this section: https://wiki.tfes.org/Cavendish_Experiment#A_Small_Effect

Since the noise highly dominates the effect, how do you know that the effect is actually being measured?

So the error is caused by errors? So 0.15% is attributable to errors, and the other 99.85%, or thereabouts, is down to the thing we are trying to measure, which is gravity. You can try to twist it as much as you like, but none of the people you are quoting are even close to suggesting that any of the experiments indicate that gravity doesn’t exist.

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Offline Tom Bishop

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Re: Cavendish experiment
« Reply #83 on: May 03, 2021, 10:21:29 PM »
The gravity effect being measured is only equivalent to the weight of a few cells, very small. That gravity effect is be being dominated over ten fold by effects which are not gravity.

How do we know if it's measuring gravity if the noise level dominates the effect being measured? The results are erratic. It could just be measuring noise in that range.

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Offline Tom Bishop

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Re: Cavendish experiment
« Reply #84 on: May 03, 2021, 10:27:28 PM »
none of the people you are quoting are even close to suggesting that any of the experiments indicate that gravity doesn’t exist.

Wrong. They clearly admit that the problem is so concerning that they don't know if they are measuring it at all.

https://www.scientificamerican.com/article/puzzling-measurement-of-big-g-gravitational-constant-ignites-debate-slide-show/

"In fact, the discrepancy is such a problem that Quinn is organizing a meeting in February at the Royal Society in London to come up with a game plan for resolving the impasse. The meeting’s title—“The Newtonian constant of gravitation, a constant too difficult to measure?”—reveals the general consternation."

Offline SteelyBob

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Re: Cavendish experiment
« Reply #85 on: May 03, 2021, 10:37:19 PM »
The gravity effect being measured is only equivalent to the weight of a few cells, very small. That gravity effect is be being dominated over ten fold by effects which are not gravity.

How do we know if it's measuring gravity if the noise level dominates the effect being measured? The results are erratic. It could just be measuring noise in that range.

Because numerous experiments all arrive at numbers that are very close to each other. That article you yourself cited mentions two different methods getting very similar results, for example.

The frustration is that discrepancies between results exceed estimated errors, meaning error estimation is poor. That in no way nullifies the results.

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Offline Tom Bishop

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Re: Cavendish experiment
« Reply #86 on: May 03, 2021, 10:44:34 PM »
Ten fold differences from the expected uncertainties aren't similar results. They are different results. The effect of gravity is dominated by other effects on that range. If we don't have a consistent effect then we cannot say that it is gravity. It could be electrostatic forces at that level.

You need to purify the experiment enough so that noise doesn't dominate the results, in order to separate one phenomena from another. They have not yet been able to do that.

From the previous link:

" But getting to the bottom of the issue is more a matter of principle to the scientists. “It’s not a thing one likes to leave unresolved,” he adds. “We should be able to measure gravity.” "

Obviously the implication there is that they can't measure gravity.

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Online Rama Set

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Re: Cavendish experiment
« Reply #87 on: May 04, 2021, 12:21:30 AM »
The same is true of gravity. It has been measured. Cavendish measured it. Lots of people have measured it and they are with 0.15% of each other for the gravitational constant. Why do you need a mechanism before you acknowledge that something is there?

The effect of gravity is much smaller than that range. The 0.15% deviation is dominated by effects which are not gravity. See this section: https://wiki.tfes.org/Cavendish_Experiment#A_Small_Effect

Since the noise highly dominates the effect, how do you know that the effect is actually being measured?

It isn't dominated, that is your own ideological editorial.  There is a small variance, just larger than they would like, but they have no doubt as to what is being measured.
Th*rk is the worst person on this website.

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Offline Tom Bishop

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Re: Cavendish experiment
« Reply #88 on: May 04, 2021, 01:15:19 AM »
It isn't dominated

If you are forced to refer to yourself as a source you may as well say nothing at all. It's a sign of defeated position. Surely if there were mountains of evidence for this on your side you would be able to quote it directly from appropriate sources in order to directly contradict it.

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Offline Iceman

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Re: Cavendish experiment
« Reply #89 on: May 04, 2021, 01:22:27 AM »
You're acting like the futurism article is the only source that matters on the topic, when the reality is that the Cavendish experiment has been performed many times (vacuum chamber, electrically grounded masses) and is continually updated and improved to explore the limits of gravitational attraction

https://arxiv.org/abs/2002.11761

Granted, no one is satisfied with the lack of precision compared to other universal constants, but science is more than just a body of knowledge, it's the search for answers to questions we might not have even though to ask yet.

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Offline Tom Bishop

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Re: Cavendish experiment
« Reply #90 on: May 04, 2021, 02:11:14 AM »
You're acting like the futurism article is the only source that matters on the topic, when the reality is that the Cavendish experiment has been performed many times (vacuum chamber, electrically grounded masses) and is continually updated and improved to explore the limits of gravitational attraction

https://arxiv.org/abs/2002.11761

Granted, no one is satisfied with the lack of precision compared to other universal constants, but science is more than just a body of knowledge, it's the search for answers to questions we might not have even though to ask yet.

That's not a Cavendish-type experiment. That's an experiment testing the Equivalence Principle with a torsion balance like these ones: https://wiki.tfes.org/Torsion_Balance_Tests

Offline fisherman

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Re: Cavendish experiment
« Reply #91 on: May 04, 2021, 03:55:20 AM »
Quote
Well, yes.  But until TV is established, acceleration up is less than UA acceleration so velocity becomes less,  etc. etc.  Would have to look at it again to see exactly where it ended up.

As far as I am concerned, it is established.  The language in the wiki is clear and if I am misunderstanding, not FEer has seen fit to correct me. 

Consider the apple and tree in a vacuum if it makes you feel better.  The principle is still the same.

The bottom line is that the EP only applies when an object is "at rest"...in an unaccelerated state. If an object is being accelerated upwards, whether it is being slowed down by drag or not, it is still being accelerated.  They can't have it both ways and apply the EP, but also claim an object is being accelerated.
There are two kinds of people in the world.  Those that can infer logical conclusions from given information

Offline c0i9z

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Re: Cavendish experiment
« Reply #92 on: May 04, 2021, 04:30:28 AM »
We have a 99.85% consistent effect. Like I said before, no one is suggesting that the constant might really be under 6 or over 7. They're just all frustrated that they can't get a precision of more than a few digits, instead of about 9, like they can for other constants. This goes back to the quoting problems I've mentioned elsewhere. None of these sources think for a moment that gravity doesn't exist or that there isn't a gravitational constant or that it isn't about 6.67. Misinterpreting quotes to pretend like they do does nothing but show a severe lack of understanding of the subject.

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Online Rama Set

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Re: Cavendish experiment
« Reply #93 on: May 04, 2021, 04:37:03 AM »
It isn't dominated

If you are forced to refer to yourself as a source you may as well say nothing at all. It's a sign of defeated position. Surely if there were mountains of evidence for this on your side you would be able to quote it directly from appropriate sources in order to directly contradict it.

I am forced to call bull shit on your mischaracterization of your own source (no one is surprised).  At no time does it say the measurement is dominated by noise.  No where.  You are making that up for hperbolic purposes.  I have already posted a link to an article which cites multiple scientific papers where they discuss the difficulties in measuring G as well as the increasing precision of their experiments.  Keep ignoring it.  I expect nothing less.
Th*rk is the worst person on this website.

Offline SteelyBob

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Re: Cavendish experiment
« Reply #94 on: May 04, 2021, 06:02:57 AM »
Ten fold differences from the expected uncertainties aren't similar results. They are different results. The effect of gravity is dominated by other effects on that range. If we don't have a consistent effect then we cannot say that it is gravity. It could be electrostatic forces at that level.

You need to purify the experiment enough so that noise doesn't dominate the results, in order to separate one phenomena from another. They have not yet been able to do that.

From the previous link:

" But getting to the bottom of the issue is more a matter of principle to the scientists. “It’s not a thing one likes to leave unresolved,” he adds. “We should be able to measure gravity.” "

From the article:

Quote
The team also took the further step of adding a second, independent way of measuring the gravitational attraction: In addition to observing how much the bar twisted, the researchers also conducted experiments with electrodes placed inside the torsion balance that prevented it from twisting. The strength of the voltage needed to prevent the rotation was directly related to the pull of gravity. “A strong point of Quinn’s experiment is the fact that they use two different methods to measure G,” says Stephan Schlamminger of the U.S. National Institute of Standards and Technology in Gaithersburg, Md., who led a separate attempt in 2006 to calculate big G using a beam balance setup. “It is difficult to see how the two methods can produce two numbers that are wrong, but yet agree with each other.”

Through these dual experiments, Quinn’s team arrived at a value of 6.67545 X 10-11 m3 kg-1 s-2. That’s 241 parts per million above the standard value of 6.67384(80) X 10-11 m3 kg-1 s-2, which was arrived at by a special task force of the International Council for Science’s Committee on Data for Science and Technology (CODATA) (pdf) in 2010 by calculating a weighted average of all the various experimental values. These values differ from one another by as much as 450 ppm of the constant, even though most of them have estimated uncertainties of only about 40 ppm. “Clearly, many of them or most of them are subject either to serious significant errors or grossly underestimated uncertainties,” Quinn says. Making matters even more complex is the fact that the new measurement is strikingly close to a calculation of big G made by Quinn and his colleagues more than 10 years ago, published in 2001, that used similar methods but a completely separate laboratory setup.
Most scientists think all these discrepancies reflect human sources of error, rather than a true inconstancy of big G. We know the strength of gravity hasn’t been fluctuating over the past 200 years, for example, because if so, the orbits of the planets around the sun would have changed, Quinn says. Still, it’s possible that the incompatible measurements are pointing to unknown subtleties of gravity—perhaps its strength varies depending on how it’s measured or where on Earth the measurements are being made?
“Either something is wrong with the experiments, or there is a flaw in our understanding of gravity,” says Mark Kasevich, a Stanford University physicist who conducted an unrelated measurement of big G in 2007 using atom interferometry. “Further work is required to clarify the situation.”

If the true value of big G turns out to be closer to the Quinn team’s measurement than the CODATA value, then calculations that depend on G will have to be revised. For example, the estimated masses of the solar system’s planets, including Earth, would change slightly. Such a revision, however, wouldn’t alter any fundamental laws of physics, and would have very little practical effect on anyone’s life, Quinn says. But getting to the bottom of the issue is more a matter of principle to the scientists.

Quinn used two completely different methods and got results that were in agreement with each other. There are numerous ways of measure G - here's an article summing up the challenges: https://aip.scitation.org/doi/10.1063/1.4994619

You can distract, deflect and quote out of context all you like, but you can't avoid the fact that the noise you say 'dominates' the results simply doesn't. Even the article you yourself points that out - yes, mismatches between different experiments in excess of the individual forecast tolerances is disappointing, but you are talking about discrepancies of 450ppm - that's 0.045% instead of 0.004%. These are tiny, tiny errors. Nobody is in any doubt that big G is around 6.67 x 10-11. The debate is around the 3/4/5th sig fig. The notion that this uncertainty means the whole concept of G is in doubt is utterly ridiculous - there is no one alternative source of attractive force that could provide such similar results across a wide range of experimental methods.

Here's an interesting update on some of the latest work on the subject. As with all science - progress is being made.

https://academic.oup.com/nsr/article/7/12/1796/5721261

I think your last point says it all:

Quote
Obviously the implication there is that they can't measure gravity.

That just shows the kind of bad faith debating style you are using. It 'obviously' shows no such thing, and twisting his words like that seems a bit desperate, frankly. He is clearly suggesting that they should be able to do better - and indeed they have, as the last link shows.


Re: Cavendish experiment
« Reply #95 on: May 04, 2021, 06:42:53 AM »
none of the people you are quoting are even close to suggesting that any of the experiments indicate that gravity doesn’t exist.

Wrong. They clearly admit that the problem is so concerning that they don't know if they are measuring it at all.

https://www.scientificamerican.com/article/puzzling-measurement-of-big-g-gravitational-constant-ignites-debate-slide-show/

"In fact, the discrepancy is such a problem that Quinn is organizing a meeting in February at the Royal Society in London to come up with a game plan for resolving the impasse. The meeting’s title—“The Newtonian constant of gravitation, a constant too difficult to measure?”—reveals the general consternation."

You “accidentally” forgot to quote this part of that article:

Quote
If the true value of big G turns out to be closer to the Quinn team’s measurement than the CODATA value, then calculations that depend on G will have to be revised. For example, the estimated masses of the solar system’s planets, including Earth, would change slightly. Such a revision, however, wouldn’t alter any fundamental laws of physics, and would have very little practical effect on anyone’s life, Quinn says. But getting to the bottom of the issue is more a matter of principle to the scientists. “It’s not a thing one likes to leave unresolved,” he adds. “We should be able to measure gravity.”

There is clearly no doubt that gravity is a thing, but our ability to measure it is imperfect because it is such a weak force.
"On a very clear and chilly day it is possible to see Lighthouse Beach from Lovers Point and vice versa...Upon looking into the telescope I can see children running in and out of the water, splashing and playing. I can see people sun bathing at the shore
- An excerpt from the account of the Bishop Experiment. My emphasis

Offline Action80

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Re: Cavendish experiment
« Reply #96 on: May 04, 2021, 05:44:00 PM »
Thank you for demonstrating that water will fall off a ball
Oh dear. Denying the evidence of your own eyes again? This is “rockets in vacuums” all over again. Those water droplets at the bottom of the ball. They didn’t fall, did they?  :)

Quote
Gravity does not exist.
So what causes things to fall and what is the mechanism behind it?
Presenting surface tension as an argument for the existence of gravity is laughable.

Material things (i.e., matter) fall because they have weight.

Matter and weight are inseparable and elemental facts.

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Offline Iceman

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Re: Cavendish experiment
« Reply #97 on: May 04, 2021, 05:48:08 PM »
Strap a scale to the bottom of your feet and go up for a rip in the vomit comet, or out into space. Think the number on the scale is going to stay constant?

Offline WTF_Seriously

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Re: Cavendish experiment
« Reply #98 on: May 04, 2021, 05:48:34 PM »

Material things (i.e., matter) fall because they have weight.


Celestial bodies don't fall yet they have weight.  You do understand what 'mechanism' means, don't you?
Distance from Sydney to Perth - We don't know.
There's a mirror floating in the sky - Yup.

Offline Action80

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Re: Cavendish experiment
« Reply #99 on: May 04, 2021, 05:52:25 PM »

Material things (i.e., matter) fall because they have weight.


Celestial bodies don't fall yet they have weight.  You do understand what 'mechanism' means, don't you?
Yeah, I understand it so much as to hear you claim the thing that somehow causes things to fall is the same thing that is somehow also responsible for keeping all things in the same place.

In short, nonsense.