Clarification on Gravity

Two questions I would like answered about the physics of gravity in the flat earth model.


#1. You guys seem to accept Einstein's postulate that the speed of light is constant for all observers traveling in any reference frame.  Otherwise, after 350 something days of accelerating at 9.81 m/s you would reach the speed of light, at which point you would no longer be able to see.

So, what happens when you approach the speed of light and cannot accelerate at 9.81 m/s anymore?  Einstein derived the theory of relativity from the postulate given above, which states that an object cannot accelerate past the speed of light.  The acceleration would then have to be gradually decreasing so the earth does not accelerate past c, and we would no longer feel the pull of gravity at the same intensity.  This would all happen within a year accelerating at 9.81 m/s.
I've read your answer for this on the FAQ page and it makes no sense.  You cannot undergo constant acceleration when arbitrarily close to the speed of light.  To do this would require infinite energy and mass.  Therefore acceleration slows down as the object approaches the speed of light and more and more of the energy used to accelerate the particle manifests itself as mass.  This is quite evident in the case of particle accelerators.

Secondly, time dilation occurring in between the celestial bodies and the earth (because spacetime is not accelerating) would cause muons emitted by the sun to live much longer than their life span of a 2*10^-6 seconds because they are now experiencing time at nearly the same rate that people on earth are (since both are arbitrarily close to c).  We should not be detecting them on earth; yet we are, and we are detecting them in great abundance.

#2.  Forget Einstein and stick with classical mechanics.  What about terminal velocity?  I believe in one of your arguments you use the fact that since ether exerts a frictional force, albeit however small, planets cannot revolve around indefinitely.  That would cause the same effect on an accelerating flat earth.  What happens when Earth reaches terminal velocity and can accelerate no more?  Everything falls off? 

Two questions I would like answered about the physics of gravity in the flat earth model.


#1. You guys seem to accept Einstein's postulate that the speed of light is constant for all observers traveling in any reference frame.  Otherwise, after 350 something days of accelerating at 9.81 m/s you would reach the speed of light, at which point you would no longer be able to see.

So, what happens when you approach the speed of light and cannot accelerate at 9.81 m/s anymore?  Einstein derived the theory of relativity from the postulate given above, which states that an object cannot accelerate past the speed of light.  The acceleration would then have to be gradually decreasing so the earth does not accelerate past c, and we would no longer feel the pull of gravity at the same intensity.  This would all happen within a year accelerating at 9.81 m/s.
I've read your answer for this on the FAQ page and it makes no sense.  You cannot undergo constant acceleration when arbitrarily close to the speed of light.  To do this would require infinite energy and mass.  Therefore acceleration slows down as the object approaches the speed of light and more and more of the energy used to accelerate the particle manifests itself as mass.  This is quite evident in the case of particle accelerators.

Secondly, time dilation occurring in between the celestial bodies and the earth (because spacetime is not accelerating) would cause muons emitted by the sun to live much longer than their life span of a 2*10^-6 seconds because they are now experiencing time at nearly the same rate that people on earth are (since both are arbitrarily close to c).  We should not be detecting them on earth; yet we are, and we are detecting them in great abundance.

#2.  Forget Einstein and stick with classical mechanics.  What about terminal velocity?  I believe in one of your arguments you use the fact that since ether exerts a frictional force, albeit however small, planets cannot revolve around indefinitely.  That would cause the same effect on an accelerating flat earth.  What happens when Earth reaches terminal velocity and can accelerate no more?  Everything falls off? 

OK, the answers to these questions are in this thread already and you could have found them by searching, but I will give you a summary here since I'm such a nice guy:

1) The Flat Earth could accelerate forever - to you and me on the surface, you have to remember our perception of time is different to that of an inertial observer, so while they may say "OMG j00 are at lyk 0.99999999999c", to you or me that's a nonsense statement, since there is no 'absolute velocity' in the Universe. To us, we're just feeling a force pushing us upwards, apparently with everything else in the Universe.

Your example of a particle accelerator is not valid since particle accelerators have a finite energy supply - since we can only speculate about the accelerative force behind the FET model we can't assume that it is 'finite' in that sense, only that so far at least it appears to be constant.

Also, how do you spacetime is not accelerating?  It certainly is in the current best RET model of the Universe (dark energy expansion of the Universe)... Even if it wasn't, are you somehow implying that spacetime is an absolute reference frame like some sort of aether? If both the Earth and Sun are accelerating we would not notice any significant additional time dilation effects in muons. I have made more comprehensive arguments against FET in the past - again, if you want to search them out and rake them over you're more than welcome.

2) Who said anything about an aether? Even if there were such a thing, couldn't it be accelerating along with everything else? If it did exert a finite frictional force, could that not be a Universal constant (hey, we are inventing physics as we go along here, right?). You need to flesh out these arguments considerably and read this thread before posting, since otherwise all future responses will be along the lines of 'lurk moar'.

2. There is no terminal velocity in a vacuum.

I think he was referring to some 'aether' as being like a vacuum medium which would lead to a terminal velocity - that's why I pulled him up on it...

I think he was referring to some 'aether' as being like a vacuum medium which would lead to a terminal velocity - that's why I pulled him up on it...

Even if that was the case, terminal velocity would be c and the point would be moot.

Quote from: Matrix on October 07, 2008, 06:47:21 AM

I think he was referring to some 'aether' as being like a vacuum medium which would lead to a terminal velocity - that's why I pulled him up on it...

Even if that was the case, terminal velocity would be c and the point would be moot.

QFT

http://www.alaska.net/~clund/e_djublonskopf/Flatearthsociety.htm

That's where I read your thing about "ether."  Unless you want to recant that.  I did not pull it up out of nowhere.


Space is NOT a perfect vacuum.  There is no such thing as a "perfect vacuum."  In fact, particle accelerators have a "more perfect" vacuum than space does. 


Why I assume spacetime is not accelerating? Well..........
If spacetime is accelerating along with the earth and the sun and everything else, then we would feel no gravitation effect puling us to the earth because the earth is not accelerating relative to spaceitme... we would instead be feeling a gravitational effect pulling us toward spacetime.. which directly contradicts observations... and then, if spacetime is accelerating, what is it accelerating relative to?



/* The Flat Earth could accelerate forever - to you and me on the surface, you have to remember our perception of time is different to that of an inertial observer, so while they may say "OMG j00 are at lyk 0.99999999999c", to you or me that's a nonsense statement, since there is no 'absolute velocity' in the Universe. To us, we're just feeling a force pushing us upwards, apparently with everything else in the Universe. */

Let me explain this another way by pointing out another inconsistency, since you don't seem to get the previous one.
There is an absolute velocity through spacetime - c.  The more you travel in space, the less you travel in time, and vice versa. 
Time and space are discrete units and are not continuous.  This was proven to be true because classical physics calculations relying on continuous frequencies yielded infinity for energy calculations.  Energy depends on amplitude and solely amplitude; therefore, one could theoretically decrease the wavelength indefinitely, yielding infinite energy.  Which obviously does not happen.  This was the problem with calculating black body radiation.

Therefore, there is a limit to how fast you can travel in space while still traveling in time: c - h (planck's constant)

Once you reach this limit, you can't accelerate anymore without reaching c.


And about the previous argument... let's dumb the numbers down a bit.  Suppose we're accelerating at 0.01 m/s, and the speed of light (the limiting speed) is 10 m/s.  Can we accelerate at 0.01 m/s forever without surpassing this limit?  Obviously not... without decreasing our acceleration, which would entail a decrease in apparent gravity.



And about the particle accelerators... even while energy is STILL BEING ADDED, we can see that more and more of this is manifesting itself as mass and not acceleration.

http://www.alaska.net/~clund/e_djublonskopf/Flatearthsociety.htm

That's where I read your thing about "ether."  Unless you want to recant that.  I did not pull it up out of nowhere.

That site is a parody of the real sure 'nuff FES.  How can we be held responsible for the silliness of the alaska.net bunch?  So, it's not our ether.

http://www.alaska.net/~clund/e_djublonskopf/Flatearthsociety.htm

That's where I read your thing about "ether."  Unless you want to recant that.  I did not pull it up out of nowhere.

That isn't us.

Space is NOT a perfect vacuum.  There is no such thing as a "perfect vacuum."  In fact, particle accelerators have a "more perfect" vacuum than space does.

 

As far as drag is concerned, it is close enough.

Why I assume spacetime is not accelerating? Well..........
If spacetime is accelerating along with the earth and the sun and everything else, then we would feel no gravitation effect puling us to the earth because the earth is not accelerating relative to spaceitme... we would instead be feeling a gravitational effect pulling us toward spacetime.. which directly contradicts observations... and then, if spacetime is accelerating, what is it accelerating relative to?

 

And about the previous argument... let's dumb the numbers down a bit.  Suppose we're accelerating at 0.01 m/s, and the speed of light (the limiting speed) is 10 m/s.  Can we accelerate at 0.01 m/s forever without surpassing this limit?  Obviously not... without decreasing our acceleration, which would entail a decrease in apparent gravity.

Yes, we can.

(rant)

You clearly have not read the rest of this thread - you are not dealing with idiots you can beat over the head by chucking in the odd Planck's constant and somehow saying "c-h" is a magical maximum speed before you get to the speed of light... That's not even dimensionally consistent!! Have you ever even done a dimensional analysis?

I'll answer your post properly later, once you've had some time to think things through a bit more thoroughly and perhaps read the rest of the thread. Plus I want to go to sleep more than I want to tell you how wrong you are (trust me, it's a tough call).

meh I'm sorry, I'll try to be dimensionally consistent despite your gross logical inconsistency in stating that an object can constantly accelerate forever and never reach a certain velocity........



/* you are not dealing with idiots */

See below for idiots....

/*  */

 
That's a very convincing response, you know.

/* Yes, we can. */

No, wtf are you smoking?  If you're accelerating constantly then your velocity is going to go over the limit sometime if your acceleration doesn't slow down....

/* As far as drag is concerned, it is close enough. */
As far as everyday times are concerned, yes, you're right.  But the earth has been accelerating for a LONG time according to your theory.



Ok fine, I'm sorry about the ether thing, that site's claims aren't exactly dissimilar to those of this site.

lrn2quote.

meh I'm sorry, I'll try to be dimensionally consistent despite your gross logical inconsistency in stating that an object can constantly accelerate forever and never reach a certain velocity........

The formula is v = (v1+v2) / (1+v2*v2/c^2). So for every 1 second of proper time, one adds 9.8 m/s to one's velocity using the above formula.

And about the previous argument... let's dumb the numbers down a bit.  Suppose we're accelerating at 0.01 m/s, and the speed of light (the limiting speed) is 10 m/s.  Can we accelerate at 0.01 m/s forever without surpassing this limit?  Obviously not...

Yes, in your frame of reference (at Earth's surface). You will not feel any changes.

without decreasing our acceleration, which would entail a decrease in apparent gravity.

Relative to an inertial observer in the universe, the Earth's acceleration decreases as it approaches c.

meh I'm sorry, I'll try to be dimensionally consistent despite your gross logical inconsistency in stating that an object can constantly accelerate forever and never reach a certain velocity........

Well that would be greatly appreciated, since calling people idiots while making the most basic, fundamental error possible in a physical argument is about the most hypocritical thing I've ever witnessed here. If you don't want people to get all defensive then try to be a bit more reasonable yourself.

Now, in answer to your question, here's a first year undergraduate special relativity question for you.  You are in a box so cannot make any observations about the Universe outside. In your hand you have an accelerometer that tells you you are accelerating upwards at 10ms^-2.  How long will it take you to reach the speed of light?

PS - as Wardogg pointed out, your posts would be a lot easier to understand if you quoted people correctly - click the 'quote' button above someone else's reply to see the syntax used to do that.

This thread makes my inner physicist cry.

It makes my outer physicist cry 

See below for idiots....
/* Yes, we can. */

No, wtf are you smoking? 

Yes, we can.

Win for Einstein!

I have a question about tidal forces. 

Wikipedia describes tidal forces as follows:

The tidal force is a secondary effect of the force of gravity and is responsible for the tides. It arises because the gravitational acceleration experienced by a large body is not constant across its diameter. One side of the body has greater acceleration than its center of mass, and the other side of the body has lesser acceleration.

We have observed in some cases where their is a very large mass, these tidal forces can be significant.  For example, the Shoemaker-Levy comet which hit Jupiter in 1994.  The gravitational pull of Jupiter was strong enough to tear the comet apart.  Is that evidence against gravity being a fictitious force?  GR disproves gravity as a force, however, as a laymen myself, I do not understand how there was no force acting on this comet.  I'm sure if a person experienced a free fall toward Jupiter, he or she would definitely feel like there was a force tearing them apart.

http://en.wikipedia.org/wiki/Comet_Shoemaker-Levy_9

Is that evidence against gravity being a fictitious force? 

A non-uniform gravitational field would cause different parts of the comet to want to move inertially in different directions at different speeds.  It basically ripped itself apart, so I would have to say no.

I agree - if you think of two ice chunks held together by their relatively weak gravitation and suddenly pull one half away due to a tidal force, the other half will carry on as it was before - both chunks see the other being 'pulled away'.  The real case is more than two chunks, of course, but the effect is to create a string of objects like that seen in the photo.

I agree - if you think of two ice chunks held together by their relatively weak gravitation and suddenly pull one half away due to a tidal force, the other half will carry on as it was before - both chunks see the other being 'pulled away'.  The real case is more than two chunks, of course, but the effect is to create a string of objects like that seen in the photo.

the word "pull" indicates a force is at work to me.  I guess I am a bit slow, I still need clarification, how does a single object following the curvature of spacetime get pulled apart without a force?

A non-uniform gravitational field would cause different parts of the comet to want to move inertially in different directions at different speeds.  It basically ripped itself apart, so I would have to say no.

I think I get what your are saying, but to me that still indicates there is a real force at work, you say "A non-uniform gravitational field would cause".  I don't see the difference between that and a real force causing parts of the comet to move at different velocities.

Also the argument that when you are in freefall you do not feel any forces acting on you.  I do not see how this is the case with the comet.

I think I get what your are saying, but to me that still indicates there is a real force at work, you say "A non-uniform gravitational field would cause".  I don't see the difference between that and a real force causing parts of the comet to move at different velocities.

Even down to the molecular level, each part of a given object wants to follow the 'local' space-time geometry (curvature in a gravitational field).  The 'force' you are talking about is inertial, as in the amount of force needed stop and object from moving in a straight line at a constant velocity, or Newton's first law.  In a non-uniform gravitational field, different sections of the object experience different degrees of curvature.  If the amount of 'force' required to prevent inertial motion of that section is not exceeded by the molecular bond, i.e. ionic/covalent, the object would break apart. 

Also the argument that when you are in freefall you do not feel any forces acting on you.  I do not see how this is the case with the comet.

Only in a uniform gravitational field.  This is what he meant by 'locally'.  Locally isn't necessarily referring to a particular size or area, it only means an area 'of sufficient size' where the gravitational field is uniform.

That pretty much nailed it on the head Robbyj.

I agree, I think I understand it better now then I did.  Thanks.

Anytime.  Good question by the way.

Now, look at their pathetic comments:

http://en.wikipedia.org/wiki/Talk:Gravitation#Last_sentence

They know what they are talking about. Give it up.

Isn't it obvious that gravity is just a result of the cohomology classes of Riemannian anti-manifold theory?

Isn't it obvious that gravity is just a result of the cohomology classes of Riemannian anti-manifold theory?

No.