FE Gravitation

No, we can conclude that you fail to realize the difference between a coordinate acceleration and a physical one.  We are undergoing a constant physical acceleration.

No, we can conclude that you fail to realize the difference between a coordinate acceleration and a physical one.  We are undergoing a constant physical acceleration.

Acceleration = rate of change of particles velocity.

I don't know what you mean by coordinate and physical acceleration, but I can assure you that if there is relative acceleration between two bodies then their relative velocities change.

I don't know what you mean by coordinate and physical acceleration, but I can assure you that if there is relative acceleration between two bodies then their relative velocities change.

Perhaps that is because you don't know the difference.  Here is a suggestion:  Look it up.

Quote from: John Jackson on March 08, 2008, 03:08:20 PM

I don't know what you mean by coordinate and physical acceleration, but I can assure you that if there is relative acceleration between two bodies then their relative velocities change.

Perhaps that is because you don't know the difference.  Here is a suggestion:  Look it up.

I looked it up and still don't know what you're talking about. Could you point out some relevant source, please.

Coordinate vs. physical acceleration

One of the greatest sources of confusion about general relativity comes from the need to distinguish between coordinate and physical accelerations.

In classical mechanics, space is preferentially mapped with a Cartesian coordinate system. Inertial motion then occurs as one moves through this space at a constant coordinate rate with respect to time. Any change in this rate of progression must be due to a force, and therefore a physical and coordinate acceleration were in classical mechanics one and the same. It is important to note that in special relativity that same kind of Cartesian coordinate system was used, with time being added as a fourth dimension and defined for an observer using the Einstein synchronization procedure. As a result, physical and coordinate acceleration correspond in special relativity too, although their magnitudes may vary.

In general relativity, the unwarranted assumption that nature provides a preferred set of coordinates is abandoned. Instead, an observer may choose a set of coordinates for their own convenience, this choice being restricted only by the condition that these coordinates be related to those of any other coordinate system by a smooth functional dependence. Only statements that do not depend on the arbitrary choice of a coordinate system by the observer (i.e. the description of a physical phenomenon) can be considered of physical relevance. This is the principle of general covariance of physical laws.

It implies, for example, that a quantity like acceleration cannot simply be described as the second derivative of the coordinate functions of a velocity, because a non zero "coordinate acceleration" may merely be an artifact of the choice of coordinates. Such an artifact occurs for the description in polar coordinates of a uniformly moving particle not passing through the (chosen!) origin. In fact, the definition of acceleration of a particle requires that one knows how to subtract velocities measured at two different points along its track in spacetime. Equivalently, it must be possible to define in an observer and coordinate invariant way which velocity vectors are constant along such a path in spacetime. This is called parallel transport. It does not come for free but requires an additional structure on spacetime called a connection. It so happens that if there is defined a "length" of all velocity vectors (which may be negative) - achieved via a Lorentzian metric - there is a natural connection called the Levi Civita connection that is uniquely determined by requiring that parallel velocity vectors have constant "length" and the technical assumption of zero torsion. It was one of Einsteins great insights that this description can be applied to describe the influence of gravity. In general relativity, gravity is seen as a consequence of the fact that parallel transport of a velocity vector may depend on the path through spacetime, not only on its endpoints. How the metric, and thereby connection and parallel transport, are determined by the transport of energy-momentum in spacetime by matter and radiation (described with the so-called stress-energy-momentum tensor) is the content of the theory of general relativity.

You are welcome.

Congratulations, you have just found the meaning of covariant derivatives. What your article simply says is, that, if a particle's world line has a non-zero second derivative (coordinate acceleration), this does not mean that it is undergoing an acceleration (physical) yet. But, if the first derivative is zero, then, certainly, both the physical and coordinate acceleration are zero.

However, the point you were making is that the Earth is not accelerating, but we are. My point still remains valid. If, in any frame of reference, the world lines of a point of an object on the Earth and a point on the Earth itself have different accelerations, whether coordinate or physical, it does not matter, then after a finite amount of time their relative position will be changed, i.e. there will be relative displacement between the two. This does not happen.

Now, please don't use some 'exotic' terms and try to look smart. Instead, answer in a straightforward manner the simple question:

If the effects we call gravity near the Earth's surface are caused solely by the acceleration of the Earth relative to some inertial frame of reference, then why are these effects the same on the upper and lower hemispheres of the Earth? By upper and lower I mean the hemispheres obtained by cutting the Earth's globe by a plane passing through the center of the Earth and being perpendicular to the acceleration vector of the Earth.

However, the point you were making is that the Earth is not accelerating, but we are.

Right, we are not talking about the Earth accelerating through space at 9.8m/s^2 as in the FE.

If, in any frame of reference, the world lines of a point of an object on the Earth and a point on the Earth itself have different accelerations

Me and the ground I am standing on have the same acceleration.  Ignoring tidal effects, obviously.

If the effects we call gravity near the Earth's surface are caused solely by the acceleration of the Earth relative to some inertial frame of reference, then why are these effects the same on the upper and lower hemispheres of the Earth?

The effect we call gravity is caused solely by our insistence that we are in an inertial frame of reference despite the fact that we are accelerating.

Hey I've got a question you guys say everything in space in FE is accelerating at 9.81 m/s^2 wouldn't that create equal gravity on all celestial bodys

So, anyone care to discuss my OP? (Or better explain this gravitational buffer idea?). As I understand Username's FE Theory, there is no need for universal accelration simulating what we would call gravity, the superior theory perhaps?

Well...to be honest: There are several theories about gravitation. One's that earth's accelerating. The other one's that earth rests on the back of a gigantic turtle (which explains the wobbling and tides, too) and gravitation is nothing but animal attraction.

Problem is we can only observe the effects of gravitation, not its causes.

Well...to be honest: There are several theories about gravitation. One's that earth's accelerating. The other one's that earth rests on the back of a gigantic turtle (which explains the wobbling and tides, too) and gravitation is nothing but animal attraction.

Problem is we can only observe the effects of gravitation, not its causes.

Let me fix that for you:

Well...to be honest: There are several ->hypothesizes<- about gravitation. One's that earth's accelerating. The other one's that earth rests on the back of a gigantic turtle (which explains the wobbling and tides, too) and gravitation is nothing but animal attraction.

Problem is we can only observe the effects of gravitation, not its causes.

The other one's that earth rests on the back of a gigantic turtle (which explains the wobbling and tides, too) and gravitation is nothing but animal attraction.

I really enjoyed that.

Usernames model makes the most sense to me even though I still don't get the math in it.

Usernames model makes the most sense to me even though I still don't get the math in it.

All any fe'ers do is make up theories.  They are all backed either stealing RE theories or they are backed by nothing. 

Quote from: Wakka Wakka on April 07, 2008, 07:02:13 AM

Usernames model makes the most sense to me even though I still don't get the math in it.

All any fe'ers do is make up theories.  They are all backed either stealing RE theories or they are backed by nothing. 

Keep posting, maybe someone someday might consider what you have to say, you never know

I don't even argue with sok unless i can PROVE him wrong. It's not worth trying to make him think he is wrong.....

I don't even argue with sok unless i can PROVE him wrong. It's not worth trying to make him think he is wrong.....

Even that is hardly worth it.

Quote from: Wakka Wakka on April 07, 2008, 07:02:13 AM

Usernames model makes the most sense to me even though I still don't get the math in it.

All any fe'ers do is make up theories.  They are all backed either stealing RE theories or they are backed by nothing. 

First of all, how do FEers explain their observations if they don't make up theories?  Seems to me that that's how science works.
Second, what "RE theories" do FEers "steal" to back their theories? 

So, would anyone like to further explore this problem in the FAQ, if such large and increasing amounts of energy are needed to accelerate FE, why is our experienced gravitation constant? (As opposed to experiencing the gravitation produced by the UA)

The acceleration does not increase.

/thread

But I never claimed that acceleration increased..  .

I believe what I said was that in order to accelerate the FE, very large amounts of energy must continously be acting on the system. This energy will create a gravitational field that the Earth should experience, elsewise FE is in violation of GR. Secondly, as our velocity increases, the energy needed to keep up the acceleration increases, thus the gravitation produced by the UA should grow stronger as this happens, but our observed gravitation does not change, how is this possible?

Basically my point is that the longer that FE undergoes acceleration, the larger FE's relativistic mass should get, which would be accompanied by an increase in gravitation.

Thank you in advance for considering this post.

Large amounts of matter bend space-time, creating geodesics, causing gravitation. Large amounts of energy don't warp space-time.

Large amounts of matter bend space-time, creating geodesics, causing gravitation. Large amounts of energy don't warp space-time.

I'm sorry, since when was GR proven wrong?

Energy is not matter.

The Energy-Momentum Tensor shows how energy changes space-time. I suggest you look this up, and the most simple parts of special relativity, the ones that show equivalance between matter and energy.
Even a photon has relativistic mass, therefore must cause change in space-time geodesics.
(http://en.wikipedia.org/wiki/Mass_in_special_relativity#The_mass_of_composite_system) This paragraph and the next 3 or 4 down are informative about this topic.

What you are saying is rediculous, mass, energy and momentum all effect space-time, I would be amazed if you found a credible source that said otherwise.

Now, I propose that you delete those last few posts from my thead (I will delete my last few in return- It may save one of us quite some embarassment).

That you for the physics lesson. Perhaps you should consider that what hypothetically propels the acceleration of the earth is not conventional matter, not conventional energy, but something else entirely.

Ah yes, "something else" this mysterious othermatter that reverses gravitational effects and acts in ways "normal" matter and energy does not. Well, why not! I can't prove it doesn't exist, for that matter, why not anything!

Who knows, maybe Gilgamesh is really did exist, and somewhere out there in this world is his magic beard, I'm sure that I can't prove he didn't exist. LOL!

If you want my opinions about this magic matter/energy, please refer to page 1. Thank you.

I have quoted my message for convienience:

Quote from: divito the truthist on February 21, 2008, 12:23:26 AM

You don't think there is a possibility that such mass exists? Or that the conditions that accompany the mass would result in such an occurrence?

As to whether such a theoretical mass may or may not exist, I don't really care to argue. (But a theory that relies on the existance of such a thing strikes me as silly). Mainly for this reason though, I do not deny the possibility that such an exotic particle may exist as some have theorized with a negetive mass, which as far as I know is allowed by General Relativity, but such a particle IS specifically denied be a posibility in the Standard Model. If you are claiming that a particle with a negetive mass, or any form of particle that is not affected by gravity, exists, then it is your responsibility to show some evidence that such a particle exists.

So far, no astrophysicist has been able to show that these things exist anywhere, or show that such a phenomenon occurs, so as far as this argument is concerned, unless the existance of such matter can be established, there is no reason to belive such particles occur in nature and therefore not a valid argument for you to use.

Secondly, even if you theorize that the mass below the mantle is made of a "gravitationally neutral matter", what of the energy that is supposedly accelerates the Earth, and the immense gravitational field it should produce. This does seem to violate the principles of general relativity in this case (the energy required to accelerate the Earth). Theorizing that the mass under the mantle is gravitationally neutral solves only part of the problem you see, unless you want to argue that it is also some kind of impossible "gravitational buffer" that prevents the gravitation of the energy under the Earth from being felt.

These are the reasons I think UA is flawed and this site would do well to adopt a theory to argue that does not require it.

Have you heard of dark energy? Or dark matter?

Have you heard of dark energy? Or dark matter?

This matter HAS an effect on space time, and it is matter, it may be exotic particle/whatever but it is normal matter and follows GR. LOL Dark matter is supposed to produce gravity, in order to explain inconsistancies in galaxy rotation speeds, ect.

Dark Matter- may exist
Anti- matter - exists
Dark Energy- may exist

*By may, I mean that it has not been proved that it exists, but it probably does.

Matter than does not act as predicted by GR: not a shred of evidence it exists, not even its effects have been seen anywhere.

Read my quoted post, it explains this adeqetly enough in my opinion

And dark energy?