Talk:Gravity

Archives

It's time to archive, per the message "This page is 145 kilobytes long. It may be helpful to move older discussion into an archive subpage. See Help:Archiving a talk page for guidance." Archiving suggestions, anyone. We might keep the most recent, if any, threads which the editors wish. But please, no off-topic or forum discussions. We have a talk page for the encyclopedia, not a soap box here.

1 Opening sentence

2 Solar System Photo

3 References

4 Opening statement revisited

5 And the distinction is...?

6 Gravity and Quantum Mechanics

7 Last sentence

8 Who is Mr. Kassner

9 Alternative Gravity Theory

10 Dark Matter

11 Gravity and gravitation

12 Scientific revolution

13 Did Newton predict gravitational lensing, and did Eddington refute Newton and confirm Einstein ?

14 Not all the GTR novel predictions listed were of previously unpredicted novel phenomena

15 1919 eclipse experiment references

16 Did GTR predict an expanding universe ?

17 So wot about the red-shift ?

18 An attractive force or not?

19 Gravity and astronomy section

20 On Ruslik's logic GTR predicts thek Moon is made of green cheese !

21 Was Hubble’s discovery of galactic red shift regarded as a test and confirmation of GTR ?

22 Gravitational table for the planets

23 Inexperienced in the field of physics - A comment on gravity?

24 Archives

--Ancheta Wis (talk) 20:54, 17 January 2009 (UTC)

Those discussions all look inactive, so I moved them to Talk:Gravitation/Archive 7. Feel free to pull a section back if I am mistaken. - Eldereft (cont.) 22:00, 17 January 2009 (UTC)

No Original Research

-- A Talk Comment --

I found this comment in the moved archive group comments.

"The purpose of an article's talk page is for discussing suggested changes to the article and ways of improving it."

Don't you suppose getting the correct science description of gravitation written would be a somewhat MAJOR step in the direction of IMPROVING the article? With other changes being a bit on the ultra-trivial side in comparison. And then discussing that real science description being major, worthwhile talk. Steve Crum (User talk:Steve Crum18:40, 18 January 2009 (UTC) —Preceding unsigned comment added by 4.254.210.92 (talk)

Welcome to Wikipedia. If you start a User Page, such as User:Example, you will typically be welcomed by the Welcoming committee, who will give you a set of links to study. For your convenience these links are shown at the top of this talk page. But currently, you should be aware that the encyclopedia has a distinct set of policies which make life easier when you attempt to contribute to this page. If you try to strike your own path please be aware that you may encounter some policies and reactions which may be counter to your intention.

For example, your current attempts to sign with your account name show that you are attempting to create links to Wikipedia:Article space rather than to Wikipedia:User space. If you want immediate personalized help then create an account, type in {{helpme}} on your talk page, save your edit, and wait for an editor to come to your assistance. To create an account, go to the login page and click create one.

One of the policies which you may find helpful in saving your time and effort on Wikipedia is No Original Research. Follow that link if you want clarification. --Ancheta Wis (talk) 02:07, 19 January 2009 (UTC)

As the editor who made the comment quoted by Steve Crum I have a little more to add to Ancheta Wis's reply. Steve Crum wrote:

"And then discussing that real science description being major, worthwhile talk."

Not all discussions which may be considered worth while by their participants are necessarily appropriate for the talk pages of Wikipedia articles. Whether they are depends on the nature of the discussion. As Ancheta Wis has pointed out, Wikipedia has numerous policy documents that spell out what is and is not appropriate. To the ones he has already listed, I would also add What Wikipedia is not, with particular reference to the sections Wikipedia is not a publisher of original thought (nor a discussion forum) and Wikipedia is not a soapbox.

—David Wilson (talk · cont) 13:45, 19 January 2009 (UTC)

In my above reply I forgot to answer Steve Crum's question:

"Don't you suppose getting the correct science description of gravitation written would be a somewhat MAJOR step in the direction of IMPROVING the article?"

Yes indeed. Wikipedia's policy requires the article to contain a description of gravitation which can be documented by reliable sources. So if the article's current description were unclear, or not properly documented, then obtaining a better one by consulting appropriate sources would certainly be a major step in improving the article, and it would be quite appropriate to discuss that on the talk page.

—David Wilson (talk · cont) 14:49, 19 January 2009 (UTC)

Alternative Theory

If the Universe is governed by the mass-dependent (Newton's law) gravitational force, the Universe shall be spherical in shape as mass-dependent gravitational force has no preference in direction. But the Unvierse is not spherical in shape, in fact flat. An alternative theory is proposed to explain this reason. A more detail description is presented in this link gravitational force Kongkokhaw (talk) 17:21, 20 January 2009 (UTC)

Has this been published in a peer reviewed journal? If not, see WP:FRINGE. Vsmith (talk) 19:04, 20 January 2009 (UTC)

Unsatisfactory sentence

The terms gravitation and gravity are mostly interchangeable in everyday use, but a distinction may be made in scientific usage. "Gravitation" is a general term describing the phenomenon by which bodies with mass are attracted to one another, while "gravity" refers specifically to the net force exerted by the Earth on objects in its vicinity as well as by other factors, such as the Earth's rotation.

The last sentence gives a flavour of what's meant, but when you read it closely it is not coherent. Can I suggest we change it to read something like this:

... while "gravity" refers specifically to the net force experienced by objects on or near the surface of the Earth. This net force is dominated by Earth's gravitational force, but also includes other components such as the centrifugual force resulting from the Earth's rotation and the buoyancy force provided by the Earth's atmosphere. —Preceding unsigned comment added by 86.134.115.227 (talk) 03:44, 11 February 2009 (UTC)

Opening sentence

The opening sentence is "Gravitation is a natural phenomenon by which objects with mass attract one another" [emphasis mine]. This sentence is not true since in Einstein's physics of gravitation (confirmed by all observations up to date so most likely the true physics) there is no attraction (though it looks like one to uninformed humans). In Einstein's gravitation there is only something called curvature of spactime and it's easy to show (even at a high school level) that it explains exactly the gravitational force. If there were also some additional attraction (a fundamental force of nature, as those uninformed humans call it) the gravitational force would be bigger than it is, and so Einstein's theory wouldn't work. So maybe it would be good to modify the opening sentence in a way that it wouldn't eliminate Einstein's physics at the onset.

Just a suggestion since I tried for years to modify this line myself to agree with Einstein's physics but it proved only that wikipedia editors don't believe that Einstein's physics is true. Since I'm doing my PhD in Einstein's gravitation I don't have this luxury of not believing in Einstein's physics but if wikipedia chooses to fool high school students (by 9:1 consensus) since grownups don't take wikipedia seriosly anyway, the opening sentence may stay as it is providing an example that the majority is sometimes dead wrong. Jim (talk) 17:40, 15 February 2009 (UTC)

You have a somewhat blinkered view of gravitation, I think. I suggest you return once you have completed your physics PhD, and then some knowledge of the history and philosophy of science. The concept of "gravitation" clearly predates Einstein by over a century. So for the first sentence to say something like "Gravitation is the field generated by matter creating a change in the curvature of spacetime" would require a fairly specific phenomenological position. Acannas (talk) 02:21, 16 February 2009 (UTC)

It should be rather something that could be understood by high school kids and would motivate them to learn more about it. E.g. "Gravitation is a natural phenomenon by which objects with mass tend to move towards each other despite that they don't attract each other". It eliminates attraction as a reason for the movement and may prompt curious kids to try to find out why those object move if there is no attraction between them. They may also ask their science teachers, which may prompt the science teachers to learn how gravitaton really works and to stop promoting the legend of attraction. Note that even Newton opposed this legend, being strongly against "action at a distance". The science teachers (at least some) may learn why the gravitational force is strictly an inertial force coming from the inside of gravitating object, which is known since 1915, when gravitation stopped being just math and bcame physics. Jim (talk) 15:46, 17 February 2009 (UTC)

I disagree with your proposal, as it implies a specific phenomenological position ("objects do not attract one another"). A more defensible position may be that "Gravitation is a natural phenomenon by which objects with mass tend to move towards each other." Period. Without taking a specific position on the "attraction" issue. Acannas (talk) 03:25, 18 February 2009 (UTC)

The math of gravitation may use "attraction" as a phenomenological model but, as we know, it is only approximate math so the model is false for sure. "Attraction" is not physics (it doesn't deliever true results). Only the inertial force may be true physics (and it is, as far as we know). So why to put garbage into the minds of kids who read wikipedia while we know for sure that it is garbage? Jim (talk) 16:14, 18 February 2009 (UTC)

You haven't addressed my reply, and instead are merely descending further into positivism. Acannas (talk) 05:14, 21 February 2009 (UTC)

People, people, people! I have changed the intro quite a bit, and most of what you say here is already addressed.Kmarinas86 ^(6sin8karma) 14:19, 21 February 2009 (UTC)

I appreciate your effort but the article about gravitation, as a minimum, should explain the simple mechanism of generation of gravitational force without the old "attraction" (spooky action at a distance) that disappeared form physics almost a century ago. Jim (talk) 20:22, 21 February 2009 (UTC)

The lead is not the appropriate place to delve deeply into the history of the subject. However, I am curious to know how you think the current lead compares to the previous one. I am neutral on this matter. The current lead has some major issues that I definitely do not like, but in some ways it is superior to the old version. Perhaps you should consider sandboxing a version of the lead and presenting it here for discussion. Acannas (talk) 00:55, 22 February 2009 (UTC)

I agree that "The lead is not the appropriate place to delve deeply into the history of the subject". Also that "The current lead has some major issues that I definitely do not like". I don't agree that "in some ways it is superior to the old version". The main issue I see here is that everybody can edit wikipedia and the great majority of people, including retired physicists, think that graviation works through "attraction". So all those people feel offended by removing word "attraction" from their texts and fight for it. So anyone who knows how gravitation works has to give up. That's why I never could explain to the high school kids of wikipedia how gravitation really works according to Einstein since it was always reverted by consensus of retired (and even still active but probably in a different branch of physics) physicists who didn't believe that Einstein's physics could be so simple as I described it and thought that I'm presenting my own theory. Jim (talk) 18:41, 22 February 2009 (UTC)

"The current lead has some major issues that I definitely do not like[....]" What are these major issues then?Kmarinas86 ^(6sin8karma) 22:56, 22 February 2009 (UTC)

The major issue is that gravitational force is not "attraction" ("spooky action at a distance" in Einstein's words) but a push from inside of gravitating object. This push is due to inertial force resulting in an interesting and rather simple way from the curvatures of space and from gravitational time dilation. Curvatures of space and gravitational time dilation are called collectively "curvatures of spacetime" and they found to be the only causes of gravitation. So gravitation is caused only by the geometry of spacetime and not by any "attractive forces" seen in the lead all over the place. Since inertial forces can't be "attractive". The mechanism of generation of gravitational force deserves an explanation in further parts of the article but unfortunately it is found nowhere in it. Which is another problem with the article. Jim (talk) 18:00, 23 February 2009 (UTC)

Thanks for making my point for me. Although I don't wish the lead to descend into too specific a phenomenological model (you had proposed stating baldly that gravitation is not attractive), I definitely disagree that the lead should be written from a predominately Newtonian perspective. If anything, the lead should summarize the main points of the article; and the chief among these seems to be how the very idea of gravitation has evolved through history. So I don't really see the current lead as a step forward, just a lateral step which only exacerbates the concerns of the present thread under discussion. Acannas (talk) 03:56, 24 February 2009 (UTC)

Jim, first, you're confusing Einstein's "spooky action at a distance", which was a reference to quantum entanglement, with plain old action at a distance (physics). Second, you're confusing action at a distance with attraction/repulsion. In Maxwell's electrodynamics unlike charges attract, but there's (said to be) no action at a distance because the interaction is mediated by the field. You could say that the particles don't really attract each other, they just respond to their local fields in such a way that they end up getting closer together—but, well, that's what it means to say that they attract each other. If we only used "attract" for direct action-at-a-distance forces then we couldn't use it at all since there don't seem to be any such forces. The other question is whether gravity is different enough from the other forces that it ought not to be called a force. I don't think it is. The Standard Model forces are all gauge forces, meaning that they can be understood very much like gravity as arising from certain "deformations of the background", except that the deformations involve internal degrees of freedom instead of just the four spacetime dimensions. Most (theoretically conceivable) forces can't be written in that way, so presumably it means something that all of the real-world forces can be. Presumably it's going to turn out that all of the "forces" are aspects of the same thing and all motion is equally inertial. That would be your typical particle physicist's guess, anyway. We shouldn't assert in the article that gravity's brand of attraction is special, since we don't know that that's true and it seems pretty likely that it isn't. -- BenRG (talk) 20:52, 24 February 2009 (UTC)

Ben, I didn't. I meant Newton's objections to attractive force based on his disbelief in action at a distance (idea of field acting on his own, also false, was not invented then). I just added to it the famous "spooky" to underline the fact that Einstein was also against action at a distance. Of course Einstein was talking about QM but Newton was talking about gravitation and both were against "action at a distance" in physics. In any case "attraction" doesn't exist neither in Einstein's gravitation, nor in QED, nor anywhere else in physics (it might be OK in math or cosmology which aren't exact sciences in the sense of describing the real world). We just shouldn't feed with false physics the high school kids who look to wikipedia for true information since there are simpler and true (as far as we know) ways of explaining gravitation. Jim (talk) 23:15, 24 February 2009 (UTC)

It looks like a hopeless situation since I have the same problem at my university. The professors want to teach the first year phsics students only the Newtonian math instead of physics of gravitation. Despite that first year students have no problems with understanding relativity since they are already taught special relativity. Yet professors think that physics students are too stupid to understand also the general relativity (or maybe professors are scared that students might be wise enough to understand it and find out that the universe can't be expanding, as the professors tell them, since it would have to violate a few physical principles). The result is that "physicists don't understand gravitation" (as one of professors said). Having no training in general relativity they don't know that the Big Bang is only math that follows the assumption of expansion, not physics, in which there is no visible expansion, just the false interpretation of the Hubble redshift. And this rdshift has also a legitimate physical interpretation contained already in Einstein's theory. "Physical theories are often wiser than their creators" [Heinrich Rudolf Hertz]. Jim (talk) 08:55, 25 February 2009 (UTC)

When we are at it I might reveal my idea of teching physics (and gravitation) that old physics professors are so much against: The last year should be dedicated to teaching the physical principles that students should absorb for their lifetimes. Once they internalize the idea that certain things are already known, as e.g. that speed of light is always $c$, the various principles of conservation, the imposibility of action at a distance (even if theists think otherwise) etc. then they can draw conclusions based on those principles and other things that they know. E.g. that if the time runs more slowly "down there" then necessarily the photons move more slowly "down there", and since the total energy of any particle is (about) its $mc^{2}$ then necessarily on any particle must act a "force" directed "down", equal $-dE/dx$, traditionally called "gravitational force". Smarter of the students may want to calculate this force and be surprised by a result that this force is exactly equal $mg$. Their science teacher should be there to help them to get through the math to get the right result. Which is not only my result but comes straight from Einstein's theory through simple differentiation that many high school students know how to do. Jim (talk) 12:17, 25 February 2009 (UTC)

We may save ourselves some time and consider that many accepted views of gravity can and must be mentioned but to do so effectively requires a certain ordering of the enyclopedic information in the article. Thus the history of gravitational theory can be related to its role in undestanding celestial phenomena. I have given a hint of this in my edits to the lead. One can divide the article according to the effects of gravity (e.g. formation of planets, stars, solarsystem, nebulas, galaxies, black holes, explosions, bending of light, etc.) and in each explaning the extent of validity of various theories of gravity, such as those of Newton and Einstein.Kmarinas86 ^(6sin8karma) 02:29, 26 February 2009 (UTC)

I agree, and I'd add that from the reader's point of view it is imporant to split the theories into physical ones, which postulate a physical mechanism of the phenomenon (like Einstein's), and mathematical (phenomenological) ones, that don't even try to guess the mechanism (like Newton's). This way the readers together with information get education that helps them to organize their knowledge. Calling all theories just "theories" would surely confuse the reader into thinking that all theories are created equal and Newton's theory is as good (or maybe better, being simpler) as Einstein's. The reader may not even notice that Einstein's theory is physical theory with so far unlimited predictive power while Newton's theory is only math (also according to Newton himself) with its predictive power limited to special cases (of "slow velocities" in the frame of observer and "weak fields"). So making a decent article on gravitation without repeating old errors might be quite a job, but then it might become one of the best articles in wikipedia. Jim (talk) 05:30, 26 February 2009 (UTC)

Gravity & Precessional Motion

It is known in the scientific community that the basic particles that make up matter are the proton,neutron,and electron. Also known is that every indivdual orbiting electron produces its own electromagnetic field while in motion. In an enviroment where matter,(atoms,molecules,mass)experience no or minimal effects from the magnetic fields produced by large bodies,(stars,planets,moons),such as the far reaches of outer space,the electrons orbiting the nucleus of said matter are more evenly distributed around said nucleus and produce no or minimal net electromagnetic output,hence,the physical effects of weightlessness.Matter that falls within or approaches the magnetic fields produced by large bodies,experience torque,causing "precessional motion",simultaneously changing the direction of its axis of rotation,and progressive angular momentum towards the large body,and causing an overall net electromagnetic output from said approraching mass.As the approaching mass feels the effects of a denser magnetic field from the large body,said mass experiences progressive angular momentum,"precessional motion",causing a greater net electromagnetic output and increased acceleration towards the large body.

````Chon Gonzalez 03/04/09```` —Preceding unsigned comment added by Chongonzalez (talk • contribs) 17:22, 4 March 2009 (UTC)

Censoring All Dissent: Does Censorship = Science?

How come there is no criticism of Newton's theory of gravitation on the page? Afraid of criticism and dissent? Is Wikipedia afraid of Neutral Points of View or not?

"Einstein’s theory of gravity is the craziest explanation of the phenomenon imaginable." -- Wallace Thornhill, physicist, 2001

"Leibniz also disagreed with other aspects of Newtonianism, such as the use of gravity, which he held to be a revival of occultism, and Newton's use of space as an absolute. Leibnizian physics defined motion and therefore space as relational." -- William E. Burns, historian, 2001

"Leibniz held that the Newtonian universe was imperfect because it occasionally requires God to intervene to prevent it from running down." -- William E. Burns, historian, 2001

"Leibniz also attacked Newtonian physical ideas, including absolute space and time, [and] the Newtonian theory of gravitation, which he charged introduced an occult force...." -- William E. Burns, historian, 2001

"Like Huygens, Leibniz never accepted Newtonian gravitation." -- Ezio Vailati, philosopher, 1997

"Newton was not the first of the age of reason. He was the last of the magicians." -- John M. Keynes, economist, 1936

"An atom differs from the solar system by the fact that it is not gravitation that makes the electrons go round the nucleus, but electricity." -- Bertrand Russell, physicist/philosopher, 1924

"...what is really wanted for a truly Natural Philosophy is a supplement to Newtonian mechanics, expressed in terms of the medium which he suspected and sought after but could not attain, and introducing the additional facts, chiefly electrical—especially the fact of variable inertia—discovered since his time…" -- Oliver J. Lodge, physicst, February 1921

"Magnetism is possessed by the whole mass of the earth and universe of heavenly bodies, and is an essence of known demonstration and laws. By adopting it we have the advantage over the gravity theory by the use of the polar relation to magnetism. A magnetic north pole presented to a magnetic south pole, or a south pole to a north pole, attracts, while a north pole to another north pole or a south pole to another repels. This gives to us a better reason than gravitation can for the elliptical orbit of the planets instead of the circular. It also gives us some light on the mystery of the tides, the philosophy of which the profoundest study has not solved. Certain facts are apparent; but for the explanation of the true theory such men as Laplace and Newton, and others more recent, have labored in vain." -- C.H. Kilmer, historian, October 1915

"Since Newton announced his universal law of gravitation, scientists have accepted and educators taught it, and rarely has it been questioned. Occasionally one has the temerity to say that gravitation is a myth, an invented word to cover scientific ignorance." -- C.H. Kilmer, historian, October 1915

"What we call mass would seem to be nothing but an appearance, and all inertia to be of electromagnetic origin." -- Henri Poincaré, physicist, 1908

"...the great truth, accidentally revealed and experimentally confirmed, is fully recognized, that this planet, with all its appalling immensity, is to electric currents virtually no more than a small metal ball...." -- Nikola Tesla, physicist, 1904

"If we were to assert that we knew more of moving objects than this their last-mentioned, experimentally-given comportment with respect to the celestial bodies, we should render ourselves culpable of a falsity." -- Ernst Mach, physicist, 1893

"...certain theoretical investigations ... appear to me to throw doubt on the utility of very minute gravitational observations." -- George H. Darwin, physicist, 1882

"The long and constant persuasion that all the forces of nature are mutually dependent, having one common origin, or rather being different manifestations of one fundamental power, has often made me think on the possibility of establishing, by experiment, a connection between gravity and electricity …no terms could exaggerate the value of the relation they would establish. -- Michael Faraday, physicist, 1865

"Thus, thinking as Newton did (i.e., that all celestial bodies are attracted to the sun and move through empty space), it is extremely improbable that the six planets would move as they do." -- Pierre L. Maupertuis, polymath, 1746

"...to establish it [gravitation] as original or primitive in certain parts of matter is to resort either to miracle or an imaginary occult quality." -- Gottfreid W. Leibniz, polymath, July 1710

"Meanwhile remote operation has just been revived in England by the admirable Mr. Newton, who maintains that it is the nature of bodies to be attracted and gravitate one towards another, in proportion to the mass of each one, and the rays of attraction it receives. Accordingly the famous Mr. Locke, in his answer to Bishop Stillingfleet, declares that having seen Mr. Newton's book he retracts what he himself said, following the opinion of the moderns, in his Essay concerning Human Understanding, to wit, that a body cannot operate immediately upon another except by touching it upon its surface and driving it by its motion. He acknowledges that God can put properties into matter which cause it to operate from a distance. Thus the theologians of the Augsburg Confession claim that God may ordain not only that a body operate immediately on divers bodies remote from one another, but that it even exist in their neighbourhood and be received by them in a way with which distances of place and dimensions of space have nothing to do. Although this effect transcends the forces of Nature, they do not think it possible to show that it surpasses the power of the Author of Nature. For him it is easy to annul the laws that he has given or to dispense with them as seems good to him, in the same way as he was able to make iron float upon water and to stay the operation of fire upon the human body." -- Gottfriend W. Leibniz, polymath, 1695

"The present does not seem to be the proper time to investigate the cause of the acceleration of natural motion [i.e., gravity], concering which various opinions have been expressed by various phiolosophers, some explaining it by attraction to the center, others to repulsion between the very small parts of the body, while still others attribute it to a certain stress in the surrounding medium which closes in behind the falling body and drives it from one of its positions to another." -- Galileo Galilei, physicist, 1638

"The example of the magnet I have hit upon is a very pretty one, and entirely suited to the subject; indeed, it is little short of being the very truth." -- Johannes Kepler, astronomer/mathematician, 1609

"It is therefore plausible, since the Earth moves the moon through its species and magnetic body, while the sun moves the planets similarly through an emitted species, that the sun is likewise a magnetic body." -- Johannes Kepler, astronomer/mathematician, 1609

"But come: let us follow more closely the tracks of this similarity of the planetary reciprocation [libration] to the motion of a magnet, and that by a most beautiful geometric demonstration, so that it might appear that a magnet has such a motion as that which we perceive in the planet." -- Johannes Kepler, astronomer/mathematician, 1609

Apparently criticism of creationist religious dogma such as that of Newton, Laplace, and Lemaitre is not tolerated. So much for NPOV Wikkidd (talk) 20:57, 6 March 2009 (UTC)

And to criticise this irrelevant post, I give you:

"Last of all Hurin stood alone. Then he cast aside his shield, and wielded an axe two-handed; and it is sung that the axe smoked in the black blood of the troll-guard of Gothmog until it withered, and each time that he slew Hurin cried 'Aure entuluva!" -- J.R.R. Tolkien, philologist, 1954. Acannas (talk) 02:29, 17 March 2009 (UTC)

I still say "gravity" is God. —Preceding unsigned comment added by 99.246.242.251 (talk) 16:10, 17 March 2009 (UTC)

Gravity + Energy

What happens to the energy used to fight gravity? Standing and sitting for instance...