[Sceptom]

Einstein also said that there is a finite maximum speed in the universe, regardless of the referential, that is the speed of light. So if the earth is accelerating upwards at 9.81 m/s2 since roughly 4 billion years, it has reached the maximum velocity a long time ago. We should thus all be floating in the air.

Please read the FAQ. More detailed explanation available here.

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.
But nothing in what I read gives any explanation. I can sum up what I read in the following way:

• there is no gravity (in the sense of Newton or General relativity); rather, the earth is accelerating and we feel it as gravity (equivalence principle)
• nothing can go faster than the speed of light
• but still, the earth accelerates always at g, and also never reaches c
• because: magic

Well, actually, I came up with that last part. But still, it's a far better explanation than what you propose, which is... nothing.

[Tintagel]

• because: magic

Actually, because math.

This may help: http://wiki.tfes.org/Universal_Acceleration#Accelerating_to_the_Speed_of_Light

[Lemmiwinks]

Einstein also said that there is a finite maximum speed in the universe, regardless of the referential, that is the speed of light. So if the earth is accelerating upwards at 9.81 m/s2 since roughly 4 billion years, it has reached the maximum velocity a long time ago. We should thus all be floating in the air.

Please read the FAQ. More detailed explanation available here.

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.
But nothing in what I read gives any explanation. I can sum up what I read in the following way:

• there is no gravity (in the sense of Newton or General relativity); rather, the earth is accelerating and we feel it as gravity (equivalence principle)
• nothing can go faster than the speed of light
• but still, the earth accelerates always at g, and also never reaches c
• because: magic

Well, actually, I came up with that last part. But still, it's a far better explanation than what you propose, which is... nothing.

They'll get you with Special relativity, mostly that you can always approach the speed of light and never reach it. Ignoring two things, one that the universe would by now be completely gone due to the lensing effect, two that SR is based on the assumption that general relativity is true.

General Relativity says gravity is real.

If gravity is real then earth cant be flat. so on so forth.

[Lemmiwinks]

• because: magic

Actually, because math.

This may help: http://wiki.tfes.org/Universal_Acceleration#Accelerating_to_the_Speed_of_Light

see?

[Sceptom]

• because: magic

Actually, because math.

This may help: http://wiki.tfes.org/Universal_Acceleration#Accelerating_to_the_Speed_of_Light

No, sorry, it doesn't help at all. All it says is that the speed of light is the maximum speed possible in the universe, which is true.
The necessary consequence of that is that the Earth cannot accelerate forever.

(Incidentally, it's quite ironic that Einstein's special relativity is used to make a point, but the rest of Einstein's ideas are completely dismissed, in particular General relativity, which functions in a universe where the Earth (and all sufficiently large bodies) are round. If that's not a perfect example of cherry picking, I don't know what it is...)

[Rama Set]

Einstein also said that there is a finite maximum speed in the universe, regardless of the referential, that is the speed of light. So if the earth is accelerating upwards at 9.81 m/s2 since roughly 4 billion years, it has reached the maximum velocity a long time ago. We should thus all be floating in the air.

Please read the FAQ. More detailed explanation available here.

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.
But nothing in what I read gives any explanation. I can sum up what I read in the following way:

• there is no gravity (in the sense of Newton or General relativity); rather, the earth is accelerating and we feel it as gravity (equivalence principle)
• nothing can go faster than the speed of light
• but still, the earth accelerates always at g, and also never reaches c
• because: magic

Well, actually, I came up with that last part. But still, it's a far better explanation than what you propose, which is... nothing.

Special Relativity dictates that as you approach c, time dilates, mass increases and length contracts such that, from your frame of reference, you appear to be accelerating at a constant rate even though your acceleration curve becomes asymptotic with the velocity c as the limit.

[Tintagel]

If gravity is real then earth cant be flat. so on so forth.

This is also not true.  Some of us believe gravitation exists.

[AMann]

It is impossible to discern acceleration from a relative frame of reference. This is called The Equivalence Principle. You might want to study it as it is one of the most basic principles in physics.

I am familiar with the equivalence principle. It states that in any small region of space-time, the effects of a gravitational field are indistinguishable from those of an appropriate acceleration of the frame of reference.

Because of this principle, if I was unable to see (if I were in a closed box) and it were in free-fall, I would not be able to tell if I was experiencing the affects of free-fall or the affects of zero-gravity.
Similarly, if I were approaching the Earth at an acceleration of 9.81m/s^2, I would not be able to tell if it was gravity working on me or in the case that Earth had no gravity that the Earth was accelerating towards me at the same rate as gravity. (The impact with the Earth would be the same).

The difference between the principle and the idea that the Earth is accelerating in an upward direction is the direction of the forces on our bodies. With gravity, I would be falling to the Earth, whereas with an accelerating Earth, a force pushing up on us. In the case of Gravity, when on the ground, there is no acceleration. In the case an an accelerating Earth, there is an acceleration 'upwards' in which case inertia would work in opposition.

But we digress...

More important than the affects of inertia if certain situations were true is the evidence that the Earth is accelerating in an 'upward' direction. Without evidence, the idea, no matter how good it sounds, is merely a guess.

Wrong. Equivalence principle is why we don't feel Earth accelerating. If you want to argue the merit of the Equivalence Principle then you are in the wrong place. I'm sure Einstein would love to hear your theories on how he was wrong, but unfortunately he's dead so I guess we'll never know.

Either way, my money is on Einstein. Unless you're claiming to be smarter than him. Are you?

I do not claim to be smarter than anyone in particular. The fact of the matter is that in spite of how smart someone is, knowledge increases with generations as it is built on itself. I would highly doubt that I am smarter than Pythagoreas either, but I am confident that my math knowledge is above his simply because we have learned more since his time and built upon his concepts.

As I already said however, we are digressing from the point of the thread, which is looking for evidence of the idea that the Earth is accelerating in an 'upward' direction, which mimics the effects of gravity.
I do know that not everyone who believes the Earth is flat throw out the concept of gravity, so I am only looking for the evidence acquired that gave rise to the idea that the Earth was accelerating as opposed to being under the effects of gravity.

[Pete Svarrior]

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.

So you knowingly and willingly tried lying to us about the Earth accelerating past the speed of light? That's not gonna win you any friends.

[Sceptom]

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.
But nothing in what I read gives any explanation. I can sum up what I read in the following way:

• there is no gravity (in the sense of Newton or General relativity); rather, the earth is accelerating and we feel it as gravity (equivalence principle)
• nothing can go faster than the speed of light
• but still, the earth accelerates always at g, and also never reaches c
• because: magic

Well, actually, I came up with that last part. But still, it's a far better explanation than what you propose, which is... nothing.

Special Relativity dictates that as you approach c, time dilates, mass increases and length contracts such that, from your frame of reference, you appear to be accelerating at a constant rate even though your acceleration curve becomes asymptotic with the velocity c as the limit.

From my frame of reference? I don't know which one is it.

The only relevant frame of reference here is the earth's one, where people live. For them (for us, actually) there is no time dilatation nor length contraction as we are in the same frame of reference.
As Earth approaches c, always more energy is needed to continue accelerating, until infinite energy would be needed, which is impossible. Any massive object cannot reach c (regardless of the frame of reference by the way). So acceleration cannot go on forever.

I don't know what you heard about special relativity, but I don't think it means what you think it means.

[Sceptom]

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.

So you knowingly and willingly tried lying to us about the Earth accelerating past the speed of light? That's not gonna win you any friends.

I don't see what is the basis for this accusation... is it a joke maybe? (English is not my first language, so there are things I sometimes wouldn't get...)

[Gulliver]

Yes, thank you, I read it, and I'm a bit familiar with special relativity and Lorentz' transformations.
But nothing in what I read gives any explanation. I can sum up what I read in the following way:

• there is no gravity (in the sense of Newton or General relativity); rather, the earth is accelerating and we feel it as gravity (equivalence principle)
• nothing can go faster than the speed of light
• but still, the earth accelerates always at g, and also never reaches c
• because: magic

Well, actually, I came up with that last part. But still, it's a far better explanation than what you propose, which is... nothing.

Special Relativity dictates that as you approach c, time dilates, mass increases and length contracts such that, from your frame of reference, you appear to be accelerating at a constant rate even though your acceleration curve becomes asymptotic with the velocity c as the limit.

From my frame of reference? I don't know which one is it.

The only relevant frame of reference here is the earth's one, where people live. For them (for us, actually) there is no time dilatation nor length contraction as we are in the same frame of reference.
As Earth approaches c, always more energy is needed to continue accelerating, until infinite energy would be needed, which is impossible. Any massive object cannot reach c (regardless of the frame of reference by the way). So acceleration cannot go on forever.

I don't know what you heard about special relativity, but I don't think it means what you think it means.

RS is correct. SR does allow for the FE acceleration to continue indefinitely, but only with at least a centillion (10^303) joules, so far. Of course, that's just unreasonable.

[Sceptom]

Special Relativity dictates that as you approach c, time dilates, mass increases and length contracts such that, from your frame of reference, you appear to be accelerating at a constant rate even though your acceleration curve becomes asymptotic with the velocity c as the limit.

From my frame of reference? I don't know which one is it.

The only relevant frame of reference here is the earth's one, where people live. For them (for us, actually) there is no time dilatation nor length contraction as we are in the same frame of reference.
As Earth approaches c, always more energy is needed to continue accelerating, until infinite energy would be needed, which is impossible. Any massive object cannot reach c (regardless of the frame of reference by the way). So acceleration cannot go on forever.

I don't know what you heard about special relativity, but I don't think it means what you think it means.

RS is correct. SR does allow for the FE acceleration to continue indefinitely, but only with at least a centillion (10^303) joules, so far. Of course, that's just unreasonable.

I did oversimplify a bit. I meant: acceleration cannot go on forever at g. I can agree on the asymptotic approach to c which means there could "always" be an acceleration, but never at g.

There is one huge problem, though: where does this tremendous energy come from? I mean, you're talking about a centillion joules but it's by far a gross underestimation. If you want to talk big numbers, try Graham's number, and still you wouldn't have enough energy to keep accelerating.

And even then, if I granted some magical energy to continue acceleration, and some magical law of physics that allows indefinite acceleration at g while never reaching c (after all, a FEer cannot adhere entirely to reality-based science, or he wouldn't be a FEer in the first place), there are still other problems: for example, I read on another thread that GPS do work with satellites. What makes them accelerate? if they have to stay at the same altitude, they have to accelerate at the same rate as the earth, otherwise they would crash as earth accelerates towards them.

[AMann]

ok - I've been all through the wiki and something that seems to be severely lacking with the flat-earth idea is evidence.

Now, this idea of the Earth accelerating upwards intrigues me. I am looking for any evidence of it. Is there any?

[Tintagel]

ok - I've been all through the wiki and something that seems to be severely lacking with the flat-earth idea is evidence.

Now, this idea of the Earth accelerating upwards intrigues me. I am looking for any evidence of it. Is there any?

The evidence for the acceleration, as indicated by the equivalence principle, is the force we experience as gravity. 

[Rama Set]

ok - I've been all through the wiki and something that seems to be severely lacking with the flat-earth idea is evidence.

Now, this idea of the Earth accelerating upwards intrigues me. I am looking for any evidence of it. Is there any?

The evidence for the acceleration, as indicated by the equivalence principle, is the force we experience as gravity. 

For it to be evidence for UA to t would have to exclude gravitation as a possibility. Your example does not do that and so it cannot be cited.

[Tintagel]

ok - I've been all through the wiki and something that seems to be severely lacking with the flat-earth idea is evidence.

Now, this idea of the Earth accelerating upwards intrigues me. I am looking for any evidence of it. Is there any?

The evidence for the acceleration, as indicated by the equivalence principle, is the force we experience as gravity. 

For it to be evidence for UA to t would have to exclude gravitation as a possibility. Your example does not do that and so it cannot be cited.

Those who support the UA agree with Einstein's reasoning that gravitation is indistinguishable from acceleration.  They simply assert that there is literally no difference between the two forces, rather than equivalence.  They cite it simply because it has been proven that the two forces are physically equivalent, and take the next logical step.

I use third person pronouns here for clarity, as I believe gravitation exists, and therefore do not support the UA model, personally.

[Rama Set]

ok - I've been all through the wiki and something that seems to be severely lacking with the flat-earth idea is evidence.

Now, this idea of the Earth accelerating upwards intrigues me. I am looking for any evidence of it. Is there any?

The evidence for the acceleration, as indicated by the equivalence principle, is the force we experience as gravity. 

For it to be evidence for UA to t would have to exclude gravitation as a possibility. Your example does not do that and so it cannot be cited.

Those who support the UA agree with Einstein's reasoning that gravitation is indistinguishable from acceleration.  They simply assert that there is literally no difference between the two forces, rather than equivalence.  They cite it simply because it has been proven that the two forces are physically equivalent, and take the next logical step.

I use third person pronouns here for clarity, as I believe gravitation exists, and therefore do not support the UA model, personally.

Regardless, it does not mean that your example is evidence for UA. It means it is evidence for either gravitation or UA.

Gravitation then goes on to predict phenomena like the perihelion of mercury; gravitational lensing variations in g corresponding to altitude, latitide and local land-masses; the cavendish experiment; and gravitational radiation. All of which have been observed.

[AMann]

ok - I've been all through the wiki and something that seems to be severely lacking with the flat-earth idea is evidence.

Now, this idea of the Earth accelerating upwards intrigues me. I am looking for any evidence of it. Is there any?

The evidence for the acceleration, as indicated by the equivalence principle, is the force we experience as gravity.

That is an explanation not evidence.
The equivalence principle only attempts to show that there is little difference between the force of gravity and an acceleration of equal proportions. It is not however evidence that our perception of gravity is based on acceleration.
What empirical evidence is there that the Earth is accelerating?

[markjo]

Those who support the UA agree with Einstein's reasoning that gravitation is indistinguishable from acceleration.

Those who use Einstein's reasoning to support the UA don't understand that the equivalence principle only applies to homogenous gravitational fields.  Once tidal forces or any other miscellaneous influences are introduced, the EP no longer applies.