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Question about gravity

Are you serious??? I'm half inclined to think you're just putting us all on...

Did I mention I was going to mock you?


































Oh yes, I did.

:wackywink:


But let us look at your statement.

If we break it down to the essential statement

"eggs are good for breakfast"
http://www.google.com/search?hl=en&safe=off&q="eggs+are+good+for+breakfast"&btnG=Search

We get 3,900 hits.

But if you break the claims about "the inverse square law" down, you end up with creationism sites, and other crazy stuff.

Can't you just simply quote or link to a credible paper or scientist to support your claim? It shouldn't be hard.
 
The discovery of truth is prevented more effectively, not by the false appearance things present and which mislead into error, not directly by weakness of the reasoning powers, but by preconceived opinion, by prejudice.

WOW Robi have you ever read your own sig?
If you don't understand what that says then shhhhh, you are just making a fool of yourself.
 
I don't understand what you're trying to say here. If Newton's law of gravity is exact, how can Einstein's law of gravity be better?

That is an excellent question. Since we have an expert here, he might be able to explain it in great detail.

No, you misunderstand me. The reason I asked isn't that I want to find out the real answer. I already know the real answer, or at least I think I do. (It is that Newton's law of gravity is not exactly correct.) I want to find out what you think the answer is. Or, rather, I am hoping that in trying to answer the question, you will realize that your position is self-contradictory. I can understand why you might not be convinced that you're wrong by someone telling you, "I'm an expert and I say that you're wrong", but surely you agree that a self-contradictory position can't be entirely right.

(Incidentally, he sure seems like an expert to me, although I guess I can't you give a good reason to take my word for it either.)
 
If you tell them it is just a theory, (as some here have pointed out), they get annoyed.

That's because anyone who says "just a theory" doesn't understand what the term means in a scientific context. Unlike colloquial useage, it's got nothing to do with our uncertainty or tentativeness about the subject. All it means is that it's a collection of concepts, laws, and what have you for explaining something about the physical world. Theories may be very tentative (string theory), they may be very well established (electrodynamics), they may be extremely successful but only in a limited context (Newtonian mechanics), but they are never just a theory. Theories do not get replaced by something better which isn't a theory. They get replaced by better theories.
 
This has now decended to the typical linguistic semantic pissing match, although I am not really suprised at the tedious inevitability, it just happened quicker than I anticipated

As far as I understand Newtonian gravitational theory starts to breakdown the faster you go and the more extreme your dimensions become. within it's boundaries it is a valid approximation of the GR gravity model, whilst discounting aspects you might not have decided to include in your model (Translation of body through space when taken from a static referance) depending on the level of accuracy of results or if GR needs to be taken into account then NP does a nice job as long as your figures don't get too big or too small.

I was taught always that it was a theory and should be referred to as a theory, and that pretty much any physical law can be considered as such, not that there is anything particularly wrong with the theory, just that outside of it's boundariesit broke down or started to lose accuracy.

Inverse Square Law as has been stated, the inverse square (and cube etc) is a mathmatical progression, and is applied to many other theories, some of these other theories also break down at extremes of numbers as well this is not due to the maths, just that this wasn't anticipated or understood or maybe even measureable at the time when the physical law was declared as a law,

Scientific Laws have Boundaries, if it helps clear things up when discussing gravity, clarify which model you wish to use, If you are discussing the cause of Gravity (a very interesting topic), then you are going to have to get over this BS semantic asumption because as it is named as a law it applies universally, there are some assumptions within all models where we are trying to discover unknowns, a lot of this is because there are unknowns, now to paraphrase we have work out what are known unknowns and unknown unknowns, sometimes you have to make an assumption to progress further, as long as the assumption works in the model you can use it to paper over the cracks for the moment, it could be that your known unknowns get fixed when you find your unknown unknowns.

Now can you pull your knobs back in and clean up that puddle
 
Let's take this example a little further and see where it goes. Imagine for a moment that the earth is completely covered with ocean - no land or ice, just water everywhere. Now an asteroid comes flying in and hits the ocean somewhere. Like a stone thrown in a pond, that sets up a circular wave that expands out from the impact point. Let's suppose the impact was the south pole, so every part of the wave is moving due north.

In the case of a stone thrown into a flat pond, 69dodge is (roughly) correct about the energy density in the ripples falling off like 1/r (ignoring friction and a few other effects). Let's see what happens instead on the curved surface of the earth.

The wave expands and eventually gets to the equator. As it keeps moving north, it actually contracts, and its energy density increases. After a while longer it will contract to zero at the north pole and smack into itself, sending up a huge plume of water.

That is not correct. It isn't even close. Such examples make it difficult to not resort to mockery. Your lack of understanding of oceans, and physical laws of motion, have led you to a completely wrong conclusion.

What do you think would happen?
 
Some laws are true by definition. Like 'A = A'. This is not a theory, it is the law of identity and is only a bullet proof Law because of the definition of '='. The inverse square law also must be true because it is a logical consequence of the math. There are many other laws in math that are true by definition.

Other laws were prematurely labeled a law when they were actually a theory. Such as "Newton's Law of Gravitation", which is listed in the 'Scientific laws named after people" link you posted. Newton's Law of Gravitation was prematurely labeled a law and later replaced by Einstein's Theory of General Relativity. If it were an actual Law, it could never be replaced. As the scientific method has become a standard in science, the word theory is used now rather than law.
DrBaltar, you are also using the word "theory" in a way that's different from how it's actually used by physicists. I too, have at some point been told that a theory is something that's believed to be true because there's some evidence to support it, and that if the evidence is weaker it's a hypothesis. But that's not how those words are used by physicists!

For example, in any introductory text on quantum field theory, you will find something called Klein-Gordon theory. This theory describes a universe with a space-time described by special relativity, where there's no gravity and no interactions at all. The only thing this universe contains is a fixed number of quantum mechanical particles of the simplest possible kind, which never interact with each other or anything else. (That's why the number of particles can never change).

Our universe definitely doesn't look like that, but this model is still called Klein-Gordon theory. Not Klein-Gordon hypothesis, Klein-Gordon fantasy or even Klein-Gordon model (the last one would actually be appropriate), but Klein-Gordon theory. This is a good example of how the word is actually used. A theory is just a statement about the properties of a possible universe. As the Klein-Gordon example shows, it doesn't even have to be our own universe.

Since a theory is just a statement, no amount of experimental evidence can change a theory into something else. It will always be a theory, even if it agrees with all the evidence, or disagrees with all the evidence. "The Earth is round" and "The Earth is flat" are both theories.

One more thing: The inverse square law of gravity isn't "a logical consequence of the math", but maybe you meant some other inverse square law, like the fact that luminosity varies with distance from the light source according to an inverse square law. That's just a result derived from the geometry.
 
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Wrong. The only reason Newtons theories are called laws is that of tradition, they are not actualy[sic] laws.

Again, if you believe that, please provide a credible scientific paper or authority to support your claim. Just repeating something doesn't make it true.

If you believe that there are absolute, immutable laws of nature that will never be shown to be incorrect or inexact, you are acting on irrational faith and are no better than a creationist.

I just can't get over the irony of that. If I was trying to write a comedy about science, that would be a great line.

No, you misunderstand me. The reason I asked isn't that I want to find out the real answer. I already know the real answer, or at least I think I do. (It is that Newton's law of gravity is not exactly correct.) I want to find out what you think the answer is.

Oh, well maybe you should say what you mean then.

I agree with the scientist and engineers who actually make things go out into space and orbit and come back, or explore the planets with probes. I agree with the people who make things work, who design and launch space ships and space stations.

I know what formulas they use, the math they use, and I know who's name is on the Laws they follow to do this. Orbital mechanics is a very exact science. They use Kepler and Newton's Laws.


Don't take my word for it however. You can learn for yourself, with little effort.

If you can find any evidence to show otherwise, please let us know. I would be most interested to discover everybody who works for NASA is wrong, and you are correct. That would be cool.
 
The hundreds of years of observation since Kepler and Newton published their theories supports both of them. They are not wrong.

But they are also not valid for some situations.
You must have a different definition of "wrong" than everyone else. Newton's theory doesn't include an "...except for in these situations" statement. It just says that the force between two masses is [insert inverse square law here], PERIOD. It says nothing else. That means that if you ever find a situation when it doesn't hold, it's wrong according to most people's definition of the word.

By the way, even in the situations where you believe the inverse square law holds, it doesn't. If you just keep increasing the accuracy of the measurements, you will eventually reach a point where the experiments disagree with Newton and agree with Einstein. And if you increase the accuracy further, the experiments will not agree with either of them.


For GPS satellites, General Relativity predicts that the atomic clocks at GPS orbital altitudes will tick faster by about 45,900 ns/day because they are in a weaker gravitational field than atomic clocks on Earth's surface. Special Relativity (SR) predicts that atomic clocks moving at GPS orbital speeds will tick slower by about 7,200 ns/day than stationary ground clocks.

So we have to account for both factors.
How can you not realize that any experimental support for GR is evidence against Newton's inverse square law of gravity?

You have proved that you can use Google when you want to. How about doing some googling on "precession perihelion general relativity" (without the quotes). You will see that we're not the first ones who have claimed that the Newton's inverse square law is wrong.
 
I know what formulas they use, the math they use, and I know who's name is on the Laws they follow to do this. Orbital mechanics is a very exact science. They use Kepler and Newton's Laws.

Kepler's laws only work for 2-body problems, so even under Newtonian physics it's only an approximation for anything in our solar system. And Newtonian physics is itself insufficient if you want to calculate a number of things with sufficient precision. The precession of Mercury's orbit is a classic example where the inclusion of relativistic effects is necessary to account for observations.

Don't take my word for it however. You can learn for yourself, with little effort.

You could stand to do some learning yourself.
 
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DrBaltar, you are also using the word "theory" in a way that's different from how it's actually used by physicists. I too, have at some point been told that a theory is something that's believed to be true because there's some evidence to support it, and that if the evidence is weaker it's a hypothesis. But that's not how those words are used by physicists!
Yeah, we can be kind of lazy about the exact words we use. But on the other hand we're not lazy about qualifying our statements (usually, forum posts don't count for example ;) ) and will, particularly when questioned, say what evidence, if any, supports something. Because of that there's really very little confusion surrounding the particular choice of 'hypothesis', 'theory', 'hairbrained idea' or whatever because people will tend to ask if they don't know the level of confidence in something (which to be fair doesn't happen much if I refer to something as a 'hairbrained idea', but you know what I mean!).
Furi is right, there's a lot of arguing about linguistics here, and none of it has any particular impact on anything.
 
But if you break the claims about "the inverse square law" down, you end up with creationism sites, and other crazy stuff.

So you regard some random googling as evidence, and aren't bothered by the fact that every single other poster in this thread disagrees with you?

Can't you just simply quote or link to a credible paper or scientist to support your claim? It shouldn't be hard.

Earth to robinson! One word: EINSTEIN.
 
This has now decended[sic] to the typical linguistic semantic pissing match, although I am not really suprised[sic] at the tedious inevitability, it just happened quicker than I anticipated


I was taught always that it was a theory and should be referred to as a theory, and that pretty much any physical law can be considered as such, not that there is anything particularly wrong with the theory, just that outside of it's boundaries it broke down or started to lose accuracy.

Semantic pissing matches usually occur when no scientific evidence can be provided.

But if you want argue about it, take it up with the Nobel Prize people.

1928 Nobel prize, SIR OWEN WILLANS RICHARDSON for his work on the thermionic phenomenon and especially for the discovery of the law named after him.

1925 Nobel prize, JAMES FRANCK and GUSTAV HERTZ for their discovery of the laws governing the impact of an electron upon an atom.

1921 Nobel Prize, ALBERT EINSTEIN for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect.

1911 Nobel prize, WILHELM WIEN for his discoveries regarding the laws governing the radiation of heat.

And on and on and on. I guess some people know more than those guys. And they think they are so smart with their Nobel Prizes and laws and stuff. You know better. It is all just theories and nobody can really prove anything. They should give those prizes back.

How can everybody be so dumb?
 
One more thing: The inverse square law of gravity isn't "a logical consequence of the math", but maybe you meant some other inverse square law, like the fact that luminosity varies with distance from the light source according to an inverse square law. That's just a result derived from the geometry.

Oh please. If you think the inverse square law does not work for the force of gravity, PLEASE just let us know where you got that from. This constant saying stuff with no logic, reason or science behind it, is too funny.
 
Oh please. If you think the inverse square law does not work for the force of gravity, PLEASE just let us know where you got that from.

General relativity. The equations demonstrating that have already been presented. That you ignored them, or were too stupid to figure out that that's what they meant, is not anyone else's fault.

The fact of the matter is, forces don't need to be 1/r2. And not all forces are. Gravity isn't, and neither is the strong nuclear force.

This constant saying stuff with no logic, reason or science behind it, is too funny.

Oh, the irony.
 
...
1928 Nobel prize, SIR OWEN WILLANS RICHARDSON for his work on the thermionic phenomenon and especially for the discovery of the law named after him.
...
And on and on and on. I guess some people know more than those guys. And they think they are so smart with their Nobel Prizes and laws and stuff. You know better. It is all just theories and nobody can really prove anything. They should give those prizes back.

How can everybody be so dumb?
What was the point of that post? Did you just want to show that the word "law" has been used outside of this thread. No one is saying it hasn't.

Oh please. If you think the inverse square law does not work for the force of gravity, PLEASE just let us know where you got that from.
From general relativity!

How many times do we have to tell you that? I see Ziggurat just did it again.

These pages explain it pretty well: 1,2. You also need to know that the inverse square law predicts elliptical orbits (with corrections for the pull from other planets and the fact the the sun isn't exactly spherical).
 

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