What is Gravity?

If NASA faked the moon landings, does the agency have any credibility at all? Was the Space Shuttle program also a hoax? Is the International Space Station another one? Do not dismiss these hypotheses offhand. Check out our wider NASA research and make up your own mind about it all.
Critical Mass
Member
Posts: 544
Joined: Tue Jul 08, 2014 10:33 pm

Re: What is Gravity?

Unread post by Critical Mass »

I suppose I'm not the only one who thinks someone could set off a small rocket in that ("nuclear bomb" proof) vacuum chamber & help answer a serious question that Cluesforum & others have raised?

Instead of needlessly "proving" that air resistance exists which is, as far as I'm aware of, a fact "not in dispute".


As for the Einstein-ien bullshit at the end of the Cox video... one can only shake their heads in amazement at the nonsensical thought processes involved.




-"Something is falling & hitting the ground with a visible & forcible impact"

-"However without the ground or a background there would be no apparent fall or impact"

-"Therefore there is no fall or force"



At least Ancient peoples beliefs in "benevolent ancestors" or "angry sky spirits" made some sense (the effects of a thunderstorm are something that one could clearly mistake for anger).. but this?
pov603
Member
Posts: 870
Joined: Thu Jun 30, 2011 8:02 pm

Re: What is Gravity?

Unread post by pov603 »

I thought the biggest vacuum chamber in the world was between Brian Cox's ears?...



******************
ADMIN NOTICE (simon) :
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
Kham
Admin
Posts: 229
Joined: Thu Jun 25, 2015 9:30 am

Re: What is Gravity?

Unread post by Kham »

I suppose I'm not the only one who thinks someone could set off a small rocket in that ("nuclear bomb" proof) vacuum chamber & help answer a serious question that Cluesforum & others have raised?
- CM

We could even start low tech, how about setting off a balloon car in the vacuum chamber first? If that works, and I know it won't, THEN we could move towards the more expensive rocket.

Image
simonshack
Administrator
Posts: 7339
Joined: Sun Oct 18, 2009 8:09 pm
Location: italy
Contact:

Re: What is Gravity?

Unread post by simonshack »

pov603 wrote:I thought the biggest vacuum chamber in the world was between Brian Cox's ears?...
Unfortunately, it seems that sound waves can actually propagate out of that particular vacuum chamber ... :P


full link: http://www.youtube.com/watch?v=6EJ8r9Rhfw8


(Hat tip to my pen friend Vinny - who sent me the link to this priceless, breakfast-table 'Coxplanation' of gravitational waves)
Painterman
Member
Posts: 95
Joined: Wed Sep 16, 2015 12:02 pm

Re: What is Gravity?

Unread post by Painterman »

JLapage,

Regarding your concerns which you highlighted in pink, I was at fault for being unclear and therefore apologize. In the sentence that immediately followed the sentence in question, I wrote:

I've never seen a counterexample cited by any "gravity denier" (apologies to George Orwell).

This was meant to clarify the preceding sentence, the pink sentence, though apparently this intent was improperly conveyed by me. So, what I meant by saying that gravity has always been found as expected between known masses in the laboratory (by itself an untenably sweeping statement, of course) is: there are no experiments known to me in which the predicted force of gravity was looked for and not found.

If you know of such an experiment, one which found a different-than-expected force of gravity under these conditions, please cite it here, as this would be a huge deal in physics of which I should be informed. Thanks.

Farcevalue,

I'm glad you posted what you did, because I've been meaning to address both of these points since flatology went into full promotion mode a year ago.
Farcevalue wrote:So, the apple falls from the tree, due to the same force that keeps the moon in place relative to the earth, but the astronots in between the apple and the moon have escaped that force.
Actually not, astronauts would also experience the force of gravity. The theory is that gravity manifests itself to astronauts as the centripetal force of their circular orbit. If there was no gravity pulling the astronauts down, they would simply fly off into space in a straight line. That a ship in space - or any object anywhere - moves in a circular path requires a force, in this case it's gravity.

centripetal force
noun
1. the force, acting upon a body moving along a curved path, that is directed toward the center of curvature of the path and constrains the body to the path.

(dictionary.reference.com)

That's the theory, in any case. I, for one, never questioned it. However, the abundant fakery of space imagery, including the complete absence of plausible high-orbit photographs of Earth, means something about "outer space" (possibly including gravity) is very different than what we're being told. I'm searching for the answer as to what that something is.
Of course Cavendish had to have balls to get a constant out of this.
The value of the gravitational constant, which Cavendish is credited with first establishing, is a consequence of the measurement units you choose, and in that sense is arbitrary: a mere mathematical artifact. What really counts about gravity as a physical phenomenon is what I tried to explain in my previous post in this thread. Namely, there is an attractive force between material objects, and the magnitude of this force depends on their masses and the distance between them.

In theory, this force is always present between all material objects. Obviously, "always" and "all" are impossible to prove in physics, so instead we wait and see if someone produces a counterexample in which the predicted gravitation is falsified. To my knowledge, we're still waiting after three centuries.
pov603
Member
Posts: 870
Joined: Thu Jun 30, 2011 8:02 pm

Re: What is Gravity?

Unread post by pov603 »

simonshack wrote:
pov603 wrote:I thought the biggest vacuum chamber in the world was between Brian Cox's ears?...
Unfortunately, it seems that sound waves can actually propagate out of that particular vacuum chamber ... :P


full link: http://www.youtube.com/watch?v=6EJ8r9Rhfw8


(Hat tip to my pen friend Vinny - who sent me the link to this priceless, breakfast-table 'Coxplanation' of gravitational waves)
Wow, that is actually 'cringeable'. I almost felt embarrassed for him.
JLapage
Member
Posts: 115
Joined: Tue Apr 23, 2013 1:38 pm

Re: What is Gravity?

Unread post by JLapage »

Replying to painterman's post of February 14th, 2016, 5:35 am ,

You stated with confidence that "Whenever this force has been sought between known masses in the lab, it has been found as expected". Whenever it was measured in the lab (giving the impression that you had done so yourself, or that you could easily cite such examples) the result was always as expected. Now in your reply you say "there are no experiments known to me in which the predicted force of gravity was looked for and not found." So you changed from measuring the force between two bodies of any mass to a body and earth? But this is assuming that we know the mass of the earth. To calculate the mass of the earth we are to accept and use Newton's Law of Universal Gravitation. But Newton's Law of Universal Gravitation is itself a theory that does not hold too well under close scrutiny (see below).
Actually not, astronauts would also experience the force of gravity. The theory is that gravity manifests itself to astronauts as the centripetal force of their circular orbit. If there was no gravity pulling the astronauts down, they would simply fly off into space in a straight line. That a ship in space - or any object anywhere - moves in a circular path requires a force, in this case it's gravity.

That is the standard explanation given and generally accepted when people really believed (and apparently some still do believe) in the theories of Newton. Newton's thought experiment was that the moon traveled in fixed circular orbits around the earth. The force (F) holding the moon in its orbit(s) is given by his Law of Universal Gravitation
F = GMm/r2 Where F = gravitational attraction, G = the gravitational constant, M = mass of one body, m = mass of the second body, r = distance between the two bodies
in order for the equation to hold, he (Newton) assumed that the moon travels in concentric circles around earth and thus that the distance r is fixed (constant) (by definition of a circle). F (the gravitational attraction holding the moon to its "true" path) If r was not a constant then the model does not hold. imagine if r was larger at one point then the moon could theoretically be gone from its orbit and if it's too close it would theoretically collide with earth and that is also according to his theory of inertia that a body set in motion remains in motion. Now it is claimed that the moon and other objects in our solar system travel in elliptical orbits and in order to keep track of the fact that everything in the universe is moving at unimaginable speeds that these objects are necessarily spiraling at various points to remain in their orbits. So the moon (in particular as an example) is therefore traveling at variable distances from the earth. Newton's theories aren't going to help you here. Remember that you said that you trust the theory
That's the theory, in any case. I, for one, never questioned it
. Good luck trying to explain what you really meant.
Of course Cavendish had to have balls to get a constant out of this.
The value of the gravitational constant, which Cavendish is credited with first establishing, is a consequence of the measurement units you choose, and in that sense is arbitrary: a mere mathematical artifact. What really counts about gravity as a physical phenomenon is what I tried to explain in my previous post in this thread. Namely, there is an attractive force between material objects, and the magnitude of this force depends on their masses and the distance between them.

In theory, this force is always present between all material objects. Obviously, "always" and "all" are impossible to prove in physics, so instead we wait and see if someone produces a counterexample in which the predicted gravitation is falsified. To my knowledge, we're still waiting after three centuries.
Henry Cavendish did not isolate the variable that he was trying to measure. He failed to eliminate many other variables. There are many problems with his experiment. I have found the following article to be quite logically written and difficult to counter showing that Cavendish's experiment is a fake.
I do not know if the Bible starts out with "In the beginnning, let
there be light", but the Bible is mostly fiction with the hints of
some historical truths, but mostly fiction. In the Cavendish
Experiment, we can say: In the beginning of the experiment, let the
first thoughts be logical thoughts.

Physics is the modern day bible. As I keep saying, Science is god, and
god is Science.

Now the Cavendish Experiment is fatally flawed, but of course in 1797,
Henry Cavendish would not have known much about electricity and
magnetism and seek to make sure that his experiment eliminated EM from
his experiment.

I went ahead and redid a mock- Cavendish Experiment with 50 lb steel
weights. I say mock because, not only did Cavendish fail to eliminate
static electricity, in that you can repeat the Cavendish Experiment
and get a torque in the torsion bar without using any weights, and
caused by applying a static electric charge, similar to making the
leaves of a electroscope move.

Let us go back to 1797 and do the Cavendish Experiment properly. We
first start with two balls of either lead or steel, preferably steel.
We suspend the steel balls near one another and independently
suspended. We put them as close together as possible without touching.
We then run a series of tests to see if the proper Cavendish
Experiment is worthwhile or doomed to perpetual failure.

Can the steel balls as they get closer and closer, have an attraction
that is as observable as when we bring two bar magnets closer and
closer, so that we cannot deny the fact that there is an "attraction"?
Not a pseudo wish desire that the Cavendish lead balls attract.

Because in the Cavendish Experiment, as I could easily see from my
mock Cavendish set-up, that I could put a weak magnet on one and both
will visibly come together. But without the magnet, I can never see
them come together.

But there is a worse culprit. The culprit that the ground where any
and all Cavendish type experiments are conducted the ground is moving,
or better, the ground is vibrating. Henry himself complained that as
he was doing the measurement, that the measurement was in oscillation.
So was Cavendish
measuring gravity, or probably, better yet, Cavendish was merely
measuring the jiggling of the ground due to Plate Tectonics of
continents adrift.

Now the Plates in South America are moving about centimeters a year.
The deflection of Cavendish Experiment was 4.1 mm. If Cavendish had
his setup in South America where the ground is noticeably jiggling,
then Cavendish would have had a far different answer. If we set-up
identical Cavendish Experiments, one near Chicago, one where Cavendish
actually did it, one near Tokyo Japan near active fault zone, etc etc,
we can expect all ranges of deflection, not because the experiment is
measuring gravity, but because it is an experiment that cannot exceed
the limitations of the fact that Plate Tectonics is a jiggling motion
that prevents the accuracy of a Cavendish Experiment to properly
function and work right.

So the question of In the Beginning of the Cavendish Experiment, Let
there be the first Logical Question: since the force of Newtonian
gravity is 10^39 weaker than the force of Electricity Magnetism for
which all material objects are composed of EM, then can there be an
experiment of Newtonian gravity that can differentiate out, separate
out the fact that EM is 10^39 stronger, and that one charge imbalance
in the Experiment would make the result a fake result.

What I am saying is that since EM is 10^39 stronger than Newtonian
gravity or General Relativity, that there never can be an experiment
on Earth that separates out EM from gravity as mass attraction. By
Logic, the Cavendish Experiment is an impossibility, to know if that
deflection was an EM deflection or a balancing imperfection or a
jiggling of the ground imperfection.

The take away by a real physicist, is that when all materials have EM
and that EM is 10^39 stronger than Newtonian gravity, that it is
impossible in an experiment to isolate the Newtonian gravity from EM.

The results of Henry Cavendish were make-belief, wish fulfillment
results, but not physics, not science for the experiment is bereft of
logic.

If someone set up the experiment at different locations around Earth,
each would experience different deflections depending on the
seismology of the ground shaking. The experiment can eliminate wind
currents and control the air. But none can control the ground of
jiggling. And none can control the fact that an object is made of EM.

Every one can witness, that no matter how large and massive of two
balls, of steel you make and place them close together, that there
never, ever was a perceptible attraction by Newtonian gravity of one
for the other. But everyone can build the tiniest of bar magnets and
notice that as you bring the two closer together, that the snap at one
another in attraction.

Also, the asteroid Ida and its moon Dactyl. Anyone doing the Cavendish
Experiment and believing it, should look at the asteroid belt, that
all the asteroids should have moons based on Cavendish Experiment, but
the fact is, that gravitational bonding is a rare phenomenon, because,
well, gravity is not Newtonian and that gravity is EM-gravity.

So the Cavendish Experiment is a fairy tale experiment, and not
physics. Physicists should be ashamed of that experiment, not proud.

Archimedes Plutonium
Reference: http://mathforum.org/kb/thread.jspa?mes ... 1&tstart=0
Painterman
Member
Posts: 95
Joined: Wed Sep 16, 2015 12:02 pm

Re: What is Gravity?

Unread post by Painterman »

JLapage wrote:So you changed from measuring the force between two bodies of any mass to a body and earth?
No, all my statements about measuring gravity have referred to the force between objects of known mass in the lab. The planet Earth is not an object in the lab.

Now I ask you, JLapage, can you cite a measurement of the force of gravity between objects of known mass in the lab that gave a result inconsistent with Newtonian gravity?
If r was not a constant then the model does not hold.
A second question:

By what reasoning do you conclude that orbital radius must be constant for the Newtonian model to hold?
Remember that you said that you trust the theory
No, I did not say that.
Critical Mass
Member
Posts: 544
Joined: Tue Jul 08, 2014 10:33 pm

Re: What is Gravity?

Unread post by Critical Mass »

Painterman wrote:No, all my statements about measuring gravity have referred to the force between objects of known mass in the lab. The planet Earth is not an object in the lab.

Now I ask you, JLapage, can you cite a measurement of the force of gravity between objects of known mass in the lab that gave a result inconsistent with Newtonian gravity?
Painterman you've been asked a number of times to bring to the forums attention these laboratory experiments you keep mentioning yet have failed to do so... why?

Instead you're asking for forum members to provide counter examples to your, so far only alleged to exist, laboratory experiments.

As far as I'm aware the only way of "measuring gravity" is by dropping steel bearings or something similar & timing their rate of fall (I'm happy to be corrected on this if that is not so)... but you seem to be implying there's another method using other objects?
JLapage
Member
Posts: 115
Joined: Tue Apr 23, 2013 1:38 pm

Re: What is Gravity?

Unread post by JLapage »

Painterman wrote:
JLapage wrote:So you changed from measuring the force between two bodies of any mass to a body and earth?
No, all my statements about measuring gravity have referred to the force between objects of known mass in the lab. The planet Earth is not an object in the lab.

Now I ask you, JLapage, can you cite a measurement of the force of gravity between objects of known mass in the lab that gave a result inconsistent with Newtonian gravity?
If r was not a constant then the model does not hold.
A second question:

By what reasoning do you conclude that orbital radius must be constant for the Newtonian model to hold?
Remember that you said that you trust the theory
No, I did not say that.
I don't think I want to play these types of games with you. One thing I can clearly show is that you did say what I claim that you did say. Just re-read the posts. I took the time to make quite a long post to leave no doubt as to what you said or failed to clearly state. But you still find a way to play mental jiu-jitsu with me, to roll with the punches so to speak.

You see I am not a physicist but I do know one thing and that is: all of Newtonian and Einsteinian theories (and frankly most of physics since the time of Newton) are thought experiments. Please read the excellent job by fellow member IC Freely under the thread 'the gods of science' (i believe that's what it's called). They (Newton and Einstein)turned physical problems into a mathematical abstractions and derived mathematical models to simulate the original physical problems/questions. So I have attacked the mathematical equation known as the Law of Universal Gravitation F = GMm/r2. I have already explained that in this model it was Newton himself who made the assumption that the orbit was circular. Again if you had read my post carefully you would see for yourself that I stated that already. So why do you ask me "By what reasoning do you conclude that orbital radius must be constant for the Newtonian model to hold?". Furthermore, from reading your posts you appear to make it look as if you were a physicist and if so you should enlighten us instead of trying to play these types of games. The only experiment used to try to support the Law of Universal Gravitation is Cavendish two balls experiment which I have already illustrated is fake science. Please read the post carefully. See the link that I have provided as the source of the brilliant guy who showed that Cavendish performed fake scientific experimentation. You have not explained how the scientific theories, that you believe in so much, can be used to calculate the mass of the earth and other celestial bodies. Please explain, and please be ready to answer questions akin to "which came first, the chicken or the egg"? Because in these mathematical models they do not make it clear.

I see something quite wrong and dishonest with scientists' approach of turning a physical problem into a mathematics problem and then turn around to ask us to falsify the physics theories in the lab. You are using the same approach. How about what's fair? You claim that you have an answer to a physical problem, you do the experiments and then come up with mathematical equations that support your laboratory results and then specify the limitations of your proposed mathematical model? In any case others have preceded me in showing the limitations of the Newtonian mathematical models. I have not discovered anything. I just read carefully to see for myself, that yes indeed there are limitations and that these limitations are enough to prove the models wrong or inadequate.

If I stated anything incorrectly or made invalid type claims please correct me.
Painterman
Member
Posts: 95
Joined: Wed Sep 16, 2015 12:02 pm

Re: What is Gravity?

Unread post by Painterman »

Here are five recent experiments to find the Newtonian gravitational constant G, each properly cited for the convenience of those who wish to scrutinize their methods.

All of these found G to be about 6.67 * 10^-11, in agreement with Cavendish, based on measurements of the gravitational force between objects of known mass in the lab, as opposed to any of the masses being the Earth or the Sun or other "outer space" object.

Fitzgerald and Armstrong
Meas. Sci. Technol. 10, 439 (1999)

F. Nolting et al.
Meas. Sci. Technol. 10, 487 (1999)

Gundlach and Merkowitz, University of Washington
Phys. Rev. Lett. 85, 2869 (2000)

T. Quinn et al., Bureau International des Poids et Mesures
Phys. Rev. Lett. 87, 111101 (2001)

Schlamminger et al., Physik-Institut der Universitat Zurich
Phys. Rev. Lett. 89, 161102 (2002)

See also:

Determination of the Gravitational Constant Using a Beam Balance
http://www.schlammi.com/pdf/diss.pdf

These five are only for starters. Many others have been conducted over the years and got roughly the same result, as predicted by Newtonian gravity.

Now, can anyone cite a few experiments that looked for gravitational force between objects of known mass in the lab and got results that are inconsistent with Newtonian gravity? Or shall we conclude there is no such experiment?
JLapage
Member
Posts: 115
Joined: Tue Apr 23, 2013 1:38 pm

Re: What is Gravity?

Unread post by JLapage »

Painterman wrote:Here are five recent experiments to find the Newtonian gravitational constant G, each properly cited for the convenience of those who wish to scrutinize their methods.

All of these found G to be about 6.67 * 10^-11, in agreement with Cavendish, based on measurements of the gravitational force between objects of known mass in the lab, as opposed to any of the masses being the Earth or the Sun or other "outer space" object.

Fitzgerald and Armstrong
Meas. Sci. Technol. 10, 439 (1999)

F. Nolting et al.
Meas. Sci. Technol. 10, 487 (1999)

Gundlach and Merkowitz, University of Washington
Phys. Rev. Lett. 85, 2869 (2000)

T. Quinn et al., Bureau International des Poids et Mesures
Phys. Rev. Lett. 87, 111101 (2001)

Schlamminger et al., Physik-Institut der Universitat Zurich
Phys. Rev. Lett. 89, 161102 (2002)

See also:

Determination of the Gravitational Constant Using a Beam Balance
http://www.schlammi.com/pdf/diss.pdf

These five are only for starters. Many others have been conducted over the years and got roughly the same result, as predicted by Newtonian gravity.

Now, can anyone cite a few experiments that looked for gravitational force between objects of known mass in the lab and got results that are inconsistent with Newtonian gravity? Or shall we conclude there is no such experiment?
Why don't you explain a little how they conducted the experiments and what you think? In any case if you are saying the first five are based on the Cavendish method then these are null and void I have already told you why.

I have no idea how they determine the force using the beam method? can you explain?
Last edited by JLapage on Mon Feb 15, 2016 9:15 pm, edited 1 time in total.
Critical Mass
Member
Posts: 544
Joined: Tue Jul 08, 2014 10:33 pm

Re: What is Gravity?

Unread post by Critical Mass »

Painterman wrote:Fitzgerald and Armstrong
Meas. Sci. Technol. 10, 439 (1999)

F. Nolting et al.
Meas. Sci. Technol. 10, 487 (1999)

Gundlach and Merkowitz, University of Washington
Phys. Rev. Lett. 85, 2869 (2000)

T. Quinn et al., Bureau International des Poids et Mesures
Phys. Rev. Lett. 87, 111101 (2001)

Schlamminger et al., Physik-Institut der Universitat Zurich
Phys. Rev. Lett. 89, 161102 (2002)

See also:

Determination of the Gravitational Constant Using a Beam Balance
http://www.schlammi.com/pdf/diss.pdf
Thanks for the link/references however please remember this is not a "link dumping site".

As JLapage says we shouldn't really drop links into threads without comment.

Forum members & any neutral readers* would like to know what you think of your link & the references**!

Either way I'll go through the "Beam Balance method" (I think I can guess what it involves based on the name...but we'll see).




* And I'm pretty much the most neutral guy you'll find on this topic as I care little for it.

** Please remember one can find "peer reviewed" references on things like Climate change "hockey sticks", Thermonuclear space earthquakes, tourniquet usage following the Boston Marathon, Apollo moon refractors & "Dark Energy"... It should therefore be clear to anyone that the value of a "peer-reviewed" reference has been much reduced.
Painterman
Member
Posts: 95
Joined: Wed Sep 16, 2015 12:02 pm

Re: What is Gravity?

Unread post by Painterman »

Thanks for the constructive feedback, Critical Mass.

Concerning the citations in my previous post, I posted them because you asked that I "bring to the forums attention these laboratory experiments you keep mentioning". Citations like that are the standard way to bring experiments to people's attention.

Otherwise, those particular experiments have no significance here beyond what I've already said about such Newton-confirming experiments in general, which forum members and neutral readers will have read.

Meanwhile, I'm sure forum members and neutral readers are still waiting for a citation or two documenting experiments that contradicted Newtonian gravity in the laboratory.
JLapage
Member
Posts: 115
Joined: Tue Apr 23, 2013 1:38 pm

Re: What is Gravity?

Unread post by JLapage »

Painterman wrote:Thanks for the constructive feedback, Critical Mass.

Concerning the citations in my previous post, I posted them because you asked that I "bring to the forums attention these laboratory experiments you keep mentioning". Citations like that are the standard way to bring experiments to people's attention.

Otherwise, those particular experiments have no significance here beyond what I've already said about such Newton-confirming experiments in general, which forum members and neutral readers will have read.

Meanwhile, I'm sure forum members and neutral readers are still waiting for a citation or two documenting experiments that contradicted Newtonian gravity in the laboratory.
I am sorry but at best I can say you are not serious. I don't want to state what is the worst that I think of you.

You make a claim and you wish to turn the burden of proof on me to disprove your claim? I don't wish to make this post long. Anyone who follows the exchanges between you and me can clearly see that you aren't serious and in fact you don't know what you are talking about.

The burden of proof lies with you because you made the claim. Unfortunately for you I did already disprove your claim. But I don't think you could discern that much. Furthermore, supposing that I was not able or refused to take the time to disprove your claim, would that make your claim valid? Here's a nice example: My claim is that I have 100 Million USD. If you ask me to prove it and my claim is indeed correct, all I have to do is to just show you my bank account balance and then you can verify that my claim is correct. But if I make the claim and ask you to show that my claim is false and you are unwilling or unable to do so this unwillingness or inability does not mean that I indeed do have 100 Million USD anywhere in this world. I took the time to explain this to you and others who are wont to say "prove it" or (as in your case) "disprove it" so that you think a little about what you are saying. Good luck to you.
Note to MODERATORS:
Please see for yourselves that this guy is playing games and if you agree with my assessment concerning him and his childish methods then take some sort of action to either reprimand him or to ban him completely. Thank you.
Post Reply