The Equivalence Principle and all its fun

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Pyrochimp

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The Equivalence Principle and all its fun
« on: March 09, 2007, 03:05:30 PM »
The equivalence principle gets talked about a lot here.  Basically, from what I can gather from the internet, it says that acceleration and gravitation are locally indistinguishable, which makes perfect sense.  However, FEers add something else to it that I haven't been able to find; they say that the equivalence principle makes it so that all objects that are being accelerated also generate their own gravitational field due to that acceleration, which makes objects gravitate in a different direction then the vector the object is accelerating in.  For example, in the Cavendish experiment (which shows gravity between two objects in a different direction besides "down", which is all most people ever experience), it's claimed that either 1. spacetime is bending and causing that gravitation (RE explanation), or 2. since the objects are accelerating, they're generating their own gravitational field, which makes the objects gravitate (FE explanation). 

I've been unable to find a reference to this anywhere, and I've read about 10 Google pages of explanations on the equivalence principle so far.  Can I have a link to something that shows that accelerating objects actually create a gravitational field?  I thought I understood the equivalence principle, but I guess not.  (Keep in mind I'm not claiming this is wrong right off the bat, I just want a source on this since I've been unable to find anything that claims accelerating objects create literal gravitational fields)
« Last Edit: March 09, 2007, 03:08:53 PM by Pyrochimp »
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
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Re: The Equivalence Principle and all its fun
« Reply #1 on: March 09, 2007, 03:07:43 PM »
That's the trouble when you bastardize science and pick out the bits that you want, ignoring everything else.

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Tom Bishop

Re: The Equivalence Principle and all its fun
« Reply #2 on: March 09, 2007, 03:29:43 PM »
The acceleration of matter warps space-time in such a way that it creates a uniform gravitational field around the object accelerating. It's called the Equivalence Principle.

For more information see http://xxx.lanl.gov/ftp/physics/papers/0204/0204044.pdf

    However one of the main tenants of general relativity is the Principle of Equivalence: A uniform gravitational field is equivalent to a uniformly accelerating frame of reference. This implies that one can create a uniform gravitational field simply by changing one’s frame of reference from an inertial frame of reference to an accelerating frame, which is a rather difficult idea to accept.

Re: The Equivalence Principle and all its fun
« Reply #3 on: March 09, 2007, 03:30:38 PM »
Yes Tom a uniform gravitational field. Earth does not have one. You lose.

Re: The Equivalence Principle and all its fun
« Reply #4 on: March 09, 2007, 03:34:05 PM »
RE 1-0 FE

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Tom Bishop

Re: The Equivalence Principle and all its fun
« Reply #5 on: March 09, 2007, 03:39:58 PM »
Quote
Yes Tom a uniform gravitational field. Earth does not have one. You lose.

The earth has gravitation. Read the FAQ.  ::)

Re: The Equivalence Principle and all its fun
« Reply #6 on: March 09, 2007, 03:42:51 PM »
Quote
Yes Tom a uniform gravitational field. Earth does not have one. You lose.

The earth has gravitation. Read the FAQ.  ::)

Hmm I'm not sure you're quoting the right person there seeing as how what you said has fuck all to do with what you're quoting. Oh well nevermind.

Why would I read the FAQ. It doesn't actually answer any of the questions that are frequently asked. Come on troll you can do better than that. I'm doing squats on your bridge retard!

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TheEngineer

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Re: The Equivalence Principle and all its fun
« Reply #7 on: March 09, 2007, 03:46:39 PM »
The equivalence principle gets talked about a lot here.  Basically, from what I can gather from the internet, it says that acceleration and gravitation are locally indistinguishable, which makes perfect sense.  However, FEers add something else to it that I haven't been able to find; they say that the equivalence principle makes it so that all objects that are being accelerated also generate their own gravitational field due to that acceleration, which makes objects gravitate in a different direction then the vector the object is accelerating in.  For example, in the Cavendish experiment (which shows gravity between two objects in a different direction besides "down", which is all most people ever experience), it's claimed that either 1. spacetime is bending and causing that gravitation (RE explanation), or 2. since the objects are accelerating, they're generating their own gravitational field, which makes the objects gravitate (FE explanation). 

Due to relativity allowing one to claim that they are stationary in a system, there better be a way to reconcile the whole gravitation thing.


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

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Pyrochimp

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Re: The Equivalence Principle and all its fun
« Reply #8 on: March 09, 2007, 03:52:36 PM »
The acceleration of matter warps space-time in such a way that it creates a uniform gravitational field around the object accelerating. It's called the Equivalence Principle.

For more information see http://xxx.lanl.gov/ftp/physics/papers/0204/0204044.pdf

    However one of the main tenants of general relativity is the Principle of Equivalence: A uniform gravitational field is equivalent to a uniformly accelerating frame of reference. This implies that one can create a uniform gravitational field simply by changing one’s frame of reference from an inertial frame of reference to an accelerating frame, which is a rather difficult idea to accept.

I think you're taking that segment of the paper a bit too literally.  I read through (well, admittedly skimmed over the equations, but payed attention to the wordy parts) it and I don't think they meant that an accelerating object actually creates a gravitational field; they only meant that if you were accelerating and you knew no information about the source of the acceleration, you would be unable to tell if the reason for that acceleration was gravitation or another source, and therefore it may as well be either.

Edit: And before you either quote me and say "exactly" or tell me how dumb I am, I'm talking about gravitation in directions other then down.  Again, in the Cavendish experiment, two objects are accelerating towards each other.  This could be gravitation or acceleration if we knew nothing about the source of that acceleration, but we know that it's NOT being caused by any form of acceleration besides gravitation (assuming you didn't use magnetic weights, perform the experiment outside on a windy day, or any other conditions that would botch the results).
« Last Edit: March 09, 2007, 04:03:41 PM by Pyrochimp »
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
[{(Diameter of Earth)*(tan[distance from Earth to sun/distance from North pole to equator])}2]/0

Re: The Equivalence Principle and all its fun
« Reply #9 on: March 09, 2007, 03:57:04 PM »
What they forget is that it's very easy to tell if you're accelerating or in a gravitational field if you, say, look out a window. That's the equivalent of getting your head out the fucking sand and observing the universe around you. Eventually you find evidence that we are in a gravitational field and not in fact accelerating with a giant disk of rock.

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Pyrochimp

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Re: The Equivalence Principle and all its fun
« Reply #10 on: March 09, 2007, 03:57:57 PM »
The equivalence principle gets talked about a lot here.  Basically, from what I can gather from the internet, it says that acceleration and gravitation are locally indistinguishable, which makes perfect sense.  However, FEers add something else to it that I haven't been able to find; they say that the equivalence principle makes it so that all objects that are being accelerated also generate their own gravitational field due to that acceleration, which makes objects gravitate in a different direction then the vector the object is accelerating in.  For example, in the Cavendish experiment (which shows gravity between two objects in a different direction besides "down", which is all most people ever experience), it's claimed that either 1. spacetime is bending and causing that gravitation (RE explanation), or 2. since the objects are accelerating, they're generating their own gravitational field, which makes the objects gravitate (FE explanation). 

Due to relativity allowing one to claim that they are stationary in a system, there better be a way to reconcile the whole gravitation thing.

I don't follow, sorry.  Do you mean that gravitation is inherently dependent on the object accelerating to create gravitation?
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
[{(Diameter of Earth)*(tan[distance from Earth to sun/distance from North pole to equator])}2]/0

Re: The Equivalence Principle and all its fun
« Reply #11 on: March 09, 2007, 05:36:25 PM »
Quote
Yes Tom a uniform gravitational field. Earth does not have one. You lose.

The earth has gravitation. Read the FAQ.  ::)

did daddy abuse you when you were young?

did mommy used to beat you?

did u get get bullied?

did u get dropped on your head?

do you see dead people?

if the answer is yes to any of the above, it would explain why you talk so much crap

dude. first of all, stop contradicting yourself. just makes you less and less credible

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GeoGuy

Re: The Equivalence Principle and all its fun
« Reply #12 on: March 09, 2007, 06:37:42 PM »
What they forget is that it's very easy to tell if you're accelerating or in a gravitational field if you, say, look out a window.
How would looking out a window tell you anything?

Re: The Equivalence Principle and all its fun
« Reply #13 on: March 09, 2007, 08:55:52 PM »
How would looking out a window tell you anything?

He was pointing out that the experience of gravity is the same as that of acceleration, but you can differentiate the type of acceleration by using your 5 senses and/or experimentation.

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Tom Bishop

Re: The Equivalence Principle and all its fun
« Reply #14 on: March 09, 2007, 08:58:55 PM »
Quote
He was pointing out that the experience of gravity is the same as that of acceleration, but you can differentiate the type of acceleration by using your 5 senses and/or experimentation.

Not if your environment is accelerating with you.

Re: The Equivalence Principle and all its fun
« Reply #15 on: March 09, 2007, 09:11:09 PM »
Not if your environment is accelerating with you.

Why don't you respond to the real question at hand....
I think you're taking that segment of the paper a bit too literally.  I read through (well, admittedly skimmed over the equations, but payed attention to the wordy parts) it and I don't think they meant that an accelerating object actually creates a gravitational field; they only meant that if you were accelerating and you knew no information about the source of the acceleration, you would be unable to tell if the reason for that acceleration was gravitation or another source, and therefore it may as well be either.

Edit: And before you either quote me and say "exactly" or tell me how dumb I am, I'm talking about gravitation in directions other then down.  Again, in the Cavendish experiment, two objects are accelerating towards each other.  This could be gravitation or acceleration if we knew nothing about the source of that acceleration, but we know that it's NOT being caused by any form of acceleration besides gravitation (assuming you didn't use magnetic weights, perform the experiment outside on a windy day, or any other conditions that would botch the results).
His points are all valid, why dont you at least try answering them...

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Tom Bishop

Re: The Equivalence Principle and all its fun
« Reply #16 on: March 09, 2007, 09:18:24 PM »
Quote
His points are all valid, why dont you at least try answering them...

Einstein's Relativity and his Principle of Equivalence walk together hand-in-hand. Break one and you break the other.

If the poster of this thread really thinks he's smarter than Einstein then perhaps he should write an opposing paper on the subject.
« Last Edit: March 09, 2007, 09:21:18 PM by Tom Bishop »

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Pyrochimp

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Re: The Equivalence Principle and all its fun
« Reply #17 on: March 09, 2007, 09:51:49 PM »
I'm definitely not as smart as Einstein, I'm just trying to understand this.  So, you claim that objects simulate gravitational fields (as in FIELDS, all possible directions, not just in the vector the object is accelerating) when they're accelerating, which is why all matter has the property of gravity?  I'd really like to know for sure, but as far as I can tell, this claim is only based on one paragraph from a paper written by a college kid that could be taken to mean different things.
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
[{(Diameter of Earth)*(tan[distance from Earth to sun/distance from North pole to equator])}2]/0

Re: The Equivalence Principle and all its fun
« Reply #18 on: March 09, 2007, 09:54:06 PM »
Einstein's Relativity and his Principle of Equivalence walk together hand-in-hand. Break one and you break the other.

If the poster of this thread really thinks he's smarter than Einstein then perhaps he should write an opposing paper on the subject.
You seem to think you're smarter than Einstein... You claim that the equivalence principle implies that any accelerating object creates a gravitational field, when this is not the case.  The equivalence principle merely refers to the fact that gravitation and acceleration evoke the same experience, thus making them indifferentiable.  Even your quote says nothing about an accelerating object creating its own gravitational field, it merely says from a different reference frame, the experiences are identical.

Quote
A uniform gravitational field is equivalent to a uniformly accelerating frame of reference.
This also implies that if the earth was uniformly accelerating, the gravitation throughout the earth would be identical, when it can easily be tested that this is not the case.
http://physics.mercer.edu/petepag/p_pend.html
Have fun with it.


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TheEngineer

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Re: The Equivalence Principle and all its fun
« Reply #19 on: March 10, 2007, 12:11:13 AM »
I don't follow, sorry.  Do you mean that gravitation is inherently dependent on the object accelerating to create gravitation?
Sorry, I kind of forgot about this.  Anyway:

The amazing thing about relativity is the frame of reference (FOR) concept.  Any observer is allowed to claim that they are at rest with respect to another FOR.  Now, this introduces certain paradoxes, to those untrained in relativity, most notably the Twins Paradox (which is very often misused on this site) and simultaneous events.  Sitting in my car doing 50 mph in a school zone, I can claim that I was not speeding, it was the school and the earth that were doing the moving.  To claim this, all reference frames must be on equal footing. 

Now, the Equivalence Principle states that there is no difference locally between acceleration and being in a gravitational field.  This implies that there is no experiment that can be done to differentiate the two.

According to General Relativity, gravitation is the result of the curvature of space which causes objects to accelerate. 

BUT, I get to claim that I am not moving.  How can I claim to not be moving yet still experience the effects of gravitation? Since I am stationary, space must warp so as to make it appear that space around me is accelerating.

Clocks run faster/slower (depending on the change) due to gravitational potential.  Now, as EP states there is no difference between gravitation and acceleration, there must be some sort of 'gravitational potential' associated with acceleration.  As EP has been shown to be correct, there is a gravitational potential in the direction of the acceleration.  A clock will run differently when placed at opposite ends of an accelerating rocket.  This warp in space also applies to all other gravitational effects including the bending of light.

Due to Relativity allowing us to choose any FOR we want and guaranteeing it will be correct, there must be some way to reconcile those paradoxes.  Simultaneous events will not be simultaneous to observers moving relative to each other, and in order for the correlation of gravity and acceleration to hold, an accelerating reference frame must distort space in such a way as to produce the effects of gravitation.


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

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Pyrochimp

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Re: The Equivalence Principle and all its fun
« Reply #20 on: March 10, 2007, 10:10:03 AM »
Hmm...never thought about it like that before.  You may have a point.  However, I think that's a bit flawed.  In your car example, you COULD say that the Earth was accelerating and you were standing still.  But, you can rule that out with simple deductive reasoning - your foot was pressing on the gas peddle in the way that always makes you go 50 MPH, not to mention that all the kids in that school zone would notice if they suddenly started accelerating 50 MPH faster.  Therefore, while it's possible by some incredible stretch of imaginaton that everything else was going 50 MPH, it's ridiculously unlikely.

That ties in, again, with the Cavendish experiment.  If you were on the masses that gravitate/accelerate towards each other, you could say that the masses were accelerating OR you could say the Earth was accelerating.  However, again, that's amazingly unlikely if you just think about it.  The Earth has never been known to change acceleration (well, never been known to change speed, it's always undergoing angular acceleration), and though the acceleration would be much less noticable for people on Earth then in your school zone example, there would still be effects.  Also, the acceleration would be going in two different directions, since the two masses are accelerating in different directions, and who knows what that would do to the Earth?  Probably not rip in two, but if one half of Earth started going one direction and the other half started going the other...

Basically, while there's a tiny, tiny chance that everything else is moving, it's almost absurd to claim so, since there's very good reason to believe that you were the one accelerating.  It's like thinking a magical pixie that lives in a mirror paints your picture on the mirror from the inside several dozens of times a second instead of the light just reflecting off the mirror back to your eye; possible, but not at all probable.
« Last Edit: March 10, 2007, 10:14:08 AM by Pyrochimp »
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
[{(Diameter of Earth)*(tan[distance from Earth to sun/distance from North pole to equator])}2]/0

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TheEngineer

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Re: The Equivalence Principle and all its fun
« Reply #21 on: March 10, 2007, 02:36:00 PM »
Hmm...never thought about it like that before.  You may have a point.  However, I think that's a bit flawed.  In your car example, you COULD say that the Earth was accelerating and you were standing still.  But, you can rule that out with simple deductive reasoning - your foot was pressing on the gas peddle in the way that always makes you go 50 MPH, not to mention that all the kids in that school zone would notice if they suddenly started accelerating 50 MPH faster.  Therefore, while it's possible by some incredible stretch of imaginaton that everything else was going 50 MPH, it's ridiculously unlikely.
I think you are confusing the point of frames of reference.  There is no point to saying which frame is correct, as they are both correct.  Relativity states that the reference frames are equal.  I can say that relative to me, the school is moving at 50mph and the school kids can claim they are stationary and I am the one moving.  Even someone on a passing airplane can claim to be at rest and the school and I are moving relative to them.  Each frame is equal and equivalent.  Frames of reference don't care which is more likely, as they are exactly the same.  So as I accelerate though the school zone, the kids can claim that my foot on the gas caused me to accelerate, while at the same time, I can claim that putting my foot on the gas caused space to warp in such a way that the school was doing the accelerating, and both would be equal.


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

Re: The Equivalence Principle and all its fun
« Reply #22 on: March 10, 2007, 02:51:47 PM »
I think you are confusing the point of frames of reference.  There is no point to saying which frame is correct, as they are both correct.  Relativity states that the reference frames are equal.  I can say that relative to me, the school is moving at 50mph and the school kids can claim they are stationary and I am the one moving.  Even someone on a passing airplane can claim to be at rest and the school and I are moving relative to them.  Each frame is equal and equivalent.  Frames of reference don't care which is more likely, as they are exactly the same.  So as I accelerate though the school zone, the kids can claim that my foot on the gas caused me to accelerate, while at the same time, I can claim that putting my foot on the gas caused space to warp in such a way that the school was doing the accelerating, and both would be equal.

The two experiences are the same, but that doesn't mean it's possible that either is occurring.  Since you're the one feeling the gravitation when your car is accelerating, and you can communicate with the school kids who say they don't feel the acceleration, you can conclude that you are accelerating, and not the school.  All types of accelerations are the same, but by making observations you can differentiate the different types.  This is about the fifth time I've said this in the past few days... this shouldn't be such a hard concept to follow..

Re: The Equivalence Principle and all its fun
« Reply #23 on: March 10, 2007, 02:57:05 PM »
FE theory relies on the fallacy that because something could be the case then it must be the case. They always seem to forget the other equally valid option that supports RE in each case. And when proof appears that it is the RE option that should be taken? Conspiracy. It's flawless in it's stupidity.

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Pyrochimp

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Re: The Equivalence Principle and all its fun
« Reply #24 on: March 10, 2007, 08:15:40 PM »
Hmm...never thought about it like that before.  You may have a point.  However, I think that's a bit flawed.  In your car example, you COULD say that the Earth was accelerating and you were standing still.  But, you can rule that out with simple deductive reasoning - your foot was pressing on the gas peddle in the way that always makes you go 50 MPH, not to mention that all the kids in that school zone would notice if they suddenly started accelerating 50 MPH faster.  Therefore, while it's possible by some incredible stretch of imaginaton that everything else was going 50 MPH, it's ridiculously unlikely.
I think you are confusing the point of frames of reference.  There is no point to saying which frame is correct, as they are both correct.  Relativity states that the reference frames are equal.  I can say that relative to me, the school is moving at 50mph and the school kids can claim they are stationary and I am the one moving.  Even someone on a passing airplane can claim to be at rest and the school and I are moving relative to them.  Each frame is equal and equivalent.  Frames of reference don't care which is more likely, as they are exactly the same.  So as I accelerate though the school zone, the kids can claim that my foot on the gas caused me to accelerate, while at the same time, I can claim that putting my foot on the gas caused space to warp in such a way that the school was doing the accelerating, and both would be equal.

Right, but only one of those would make sense, and that's what I'm talking about.  You COULD say that putting your foot on the gas pedal made the entire Earth move and somehow keep you stationary, but if you come back from physics-land to the real world, you realize that's silly.
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
[{(Diameter of Earth)*(tan[distance from Earth to sun/distance from North pole to equator])}2]/0

Re: The Equivalence Principle and all its fun
« Reply #25 on: March 10, 2007, 09:14:33 PM »
Earth's gravitational field is not uniform . . . an accelerating reference frame would produce a UNIFORM field . . . you lose Tom Bishop, and whoever else believes in FE theory. FE theory cannot explain those non-uniformities, which can be observed and measured by anyone writing to this website.

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TheEngineer

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Re: The Equivalence Principle and all its fun
« Reply #26 on: March 11, 2007, 08:31:45 AM »
Quote from: Pyrochimp link=topic=11362.msg148395#msg148395
Right, but only one of those would make sense, and that's what I'm talking about.  You COULD say that putting your foot on the gas pedal made the entire Earth move and somehow keep you stationary, but if you come back from physics-land to the real world, you realize that's silly.
Why is that silly?  Relative to me, that's exactly what happened.  There is no preferred frame of reference in relativity. 


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

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Pyrochimp

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Re: The Equivalence Principle and all its fun
« Reply #27 on: March 11, 2007, 09:01:40 AM »
Quote from: Pyrochimp link=topic=11362.msg148395#msg148395
Right, but only one of those would make sense, and that's what I'm talking about.  You COULD say that putting your foot on the gas pedal made the entire Earth move and somehow keep you stationary, but if you come back from physics-land to the real world, you realize that's silly.
Why is that silly?  Relative to me, that's exactly what happened.  There is no preferred frame of reference in relativity. 

I know, I know.  Let's ignore relativity for just a minute.  Is there a car that can move the entire planet?  I know according to relativity, yes, but don't think relativity.  Is there a car that can possibly produce enough force to accelerate a whole planet?  A car producing enough force to accelerate the same car is much, much more possible.
Some people are ****ing stupid! ~ George Carlin

Mathematical proof of the flat Earth:
[{(Diameter of Earth)*(tan[distance from Earth to sun/distance from North pole to equator])}2]/0

Re: The Equivalence Principle and all its fun
« Reply #28 on: March 11, 2007, 11:12:17 AM »
Why is that silly?  Relative to me, that's exactly what happened.  There is no preferred frame of reference in relativity. 
Yes, if you're purely using vision to observe the situation, you could say that the entire earth is moving underneath you.  You have your sense of touch, however, and with it you're able to feel the force on yourself, and confirm that you are the one accelerating.  It's as simple as that.

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TruClint

Re: The Equivalence Principle and all its fun
« Reply #29 on: March 11, 2007, 11:45:01 AM »
I havn't bothered to read anything since Tom's link...

Does it not seem odd that considering the fact that "FE'ers" believe that the government is conspiring against the people trying to tell them that the Earth is Round when it is actually flat, yet when asked a question about something Tom ,an FE'er, actually posts a GOVERNMENT link?

Sorry, just thought I'd point that out.

Does this not actually make the Flat Earth Theory a conspiracy in itself?  Or am I just pulling a FE'er here?