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Is a circle spinning near c still a circle?  

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  1. 1. Is a circle spinning near c still a circle?



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I am not sure what sayo is wanting me to explain. it is pretty simple.

I simply wanted you to explain your argument in a clearer and more comprehensive fashion, but since you seem to want to just have any old argument I couldn't care less.

 

Given that the radius of a circle is the distance between a point on the circumference and the center, if the circumference increases due to relativistic effects I don't see how the radius can stay the same, even if those rel. effects do not apply to it. Surely it increases simply because the circumference does?

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It should. If the circumfrence gets bigger, then the circle is wider, so the radius also has to expand. It's not like the radius is a fixed object.

Well I am guessing the way around that is that the disc distorts (perhaps adopts non-euclidean geometry), but then it's not a circle.

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I simply wanted you to explain your argument in a clearer and more comprehensive fashion' date=' but since you seem to want to just have any old argument I couldn't care less.

 

Given that the radius of a circle is the distance between a point on the circumference and the center, if the circumference increases due to relativistic effects I don't see how the radius can stay the same, even if those rel. effects do not apply to it. Surely it increases simply because the circumference does?[/quote']

 

 

ok, lets try to be more clear.

 

given:

 

as speed-->c, distance shrinks in direction of motion

 

pi= circumference/diameter

 

equation of circle is [math](x-h)^2+(y-k)^2=r^2[/math]

 

radius has no length in the direction of motion

 

circumference shrinks

 

radius and center stay the same

 

therefore:

 

it is still a circle

 

pi is not a constant

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ok' date=' lets try to be more clear.

 

given:

 

as speed-->c, distance shrinks in direction of motion

 

pi= circumference/diameter

 

equation of circle is http://www.blike.com/tex/lateximg/pictures/7080388855e2e65d5665478c67051038.gif

 

radius has no length in the direction of motion

 

circumference shrinks

 

radius and center stay the same

 

therefore:

 

it is still a circle

 

pi is not a constant

IF THE CIRCUMFRENCE SHRINKS, then the stupid circle is smaller, meaning the radius is smaller. The radius is NOT fixed. 4f08e3dba63dc6d40b22952c7a9dac6d.gif is a constant.

ps: Sayo: Why were all of the mods in IRC but not talking to me?

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There's a difference between an outside observer sees and what actually happens, you know. That's the effect of time dilation.

 

No, there is no difference as what 'actually' happens is frame dependent. What you are doing is suggesting that there is a prefered frame in relativty, this goes against the fundamentals of the theory of relativty.

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No, there is no difference as what 'actually' happens is frame dependent. What you are doing is suggesting that there is a prefered frame in relativty, this goes against the fundamentals of the theory of relativty.

I'm not sure he wrote what he meant to say.

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I don't think the radius is a strict line exactly. The definition of it would be the distance from the circumfrence to the enter of the circle. The radius isn't an actual, physical part of the circle like the circumfrence is and therefore I don't believe it responds to relativity (or whatever you're saying). It simple adjusts as the circumfrence adjusts because that is the definition of it.

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the radius only has one dimension and it doesn't shrink due to motion. the cercumference has nothing to do with if an object is a circle; it is just the length of the distance from one point in the set to itself.

 

 

edit: it still has the same equation, it is still a circle.

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So the big question we all want answering is "is it still a circle?"

 

Yes, for example the geodesics on the surface of a sphere run along what we call still call 'great circles'.

 

It also meets the defintion as a set of points equidistant from a given point.

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the radius only has one dimension and it doesn't shrink due to motion.

You don't get what we're saying. All that's telling us it that the radius does not shrink due to relativity.

 

It does not tell us that the radius does not shrink "at all".

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Yes' date=' for example the geodesics on the surface of a sphere run along what we call still call 'great circles'.

It also meets the defintion as a set of points equidistant from a given point.[/quote']

Do you know of any representations of that geometry I can take a look at?

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