Can someone interpret this Einstein quote?

[Seminole Boy]

End of chapter 28.

"The great power possessed by the general principle of relativity lies in the comprehensive limitation which is imposed on the laws of nature..."

 

[ash64449]

End of chapter 28.

"The great power possessed by the general principle of relativity lies in the comprehensive limitation which is imposed on the laws on nature..."

Yes. It is because in order to describe Gravity, It went beyond the limitation of nature. Have you heard of Euclid's Geometry? It deals with space as being flat. Every experiment was done like this. Because the Space was considered flat, It assumes that only one straight line can go through two points,Angle sum property of triangle is 180 degrees. Two lines which was parallel always remain parallel. These are some laws of nature. Now Do you know what is the limitation of these idea? Can you tell me the limitation in only one straight line can pass through two points?

 

[Seminole Boy]

Ash, I cannot understand what you're trying to say.

Also, I believe many scientists think the universe (which includes space) is flat, so I'm not sure if I'm following you.

 

[ash64449]

Ash, I cannot understand what you're trying to say.

Do you believe that in all cases angle sum property of triangle is 180 degrees? Do you believe that two parallel lines will never meet?

 

[ash64449]

Ash, I cannot understand what you're trying to say.

Also, I believe many scientists think the universe (which includes space) is flat, so I'm not sure if I'm following you.

Yes. The universe is flat. I am not saying anything about that. You want to understand What that quote means na? I am not talking about the universe.I am talking about Gravity.

 

[ash64449]

Ash, I cannot understand what you're trying to say.

Also, I believe many scientists think the universe (which includes space) is flat, so I'm not sure if I'm following you.

Yes. the space is flat.But on some circumstances it changes. Do you know how?

 

[WannabeNewton]

Ok I have no idea what ash64449 is talking about but it seems rather clear that Einstein is talking about general covariance: http://en.wikipedia.org/wiki/General_covariance

 

[ash64449]

Ok I have no idea what ash64449 is talking about but it seems rather clear that Einstein is talking about general covariance: http://en.wikipedia.org/wiki/General_covariance

Why not?? Do you think that Angle sum property of triangle will add up to 180 degrees in curved space?

 

[Seminole Boy]

I do not know what angle sum property of triangle means. I'm a graduate student in an English program. I think in language (and yes, I'm aware this is not a good thing when it comes to physics!). Do I believe that two parallel lines will never meet? Good question. If space has no boundaries and nothing affects the motion of these lines, I do not see how they will ever meet, if everything stays constant.

 

[WannabeNewton]

Why not?? Do you think that Angle sum property of triangle will add up to 180 degrees in curved space?

This has absolutely nothing to do with the quote Seminole Boy talked about so why are you even bringing it up?

 

[ash64449]

I do not know what angle sum property of triangle means. I'm a graduate student in an English program. I think in language (and yes, I'm aware this is not a good thing when it comes to physics!). Do I believe that two parallel lines will never meet? Good question. If space has no boundaries and nothing affects the motion of these lines, I do not see how they will ever meet, if everything stays constant.

Well,think about two lights as parallel. Have you heard like this: Light bends in the presence of gravity?

 

[Seminole Boy]

Newton:

Straight from wikipedia: "The essential idea is that coordinates do not exist a priori in nature..."

What does this mean? Or, please explain it for the nonscientist (me).

 

[WannabeNewton]

Newton:

Straight from wikipedia: "The essential idea is that coordinates do not exist a priori in nature..."

What does this mean? Or, please explain it for the nonscientist (me).

Nature doesn't have some prescribed coordinate system specially adapted to the laws of physics so why should one coordinate system be any more special than another when writing down the laws of physics?

 

[ash64449]

This has absolutely nothing to do with the quote Seminole Boy talked about so why are you even bringing it up?

Well i will explain.. These are some limitations of laws of nature such as Euclid's axioms. It states that Angle sum property of triangle is 180 degrees. There is only one straight line passing through two points. These are some limits of law of nature. Albert Einstein said that general relativity goes beyond the law of nature. It does! Energy bends space-time. This curvature is gravity. When space is curved two parallel lines which where parallel is no longer parallel.. Angle sum property of triangle is more than 180 degrees like in surface of Earth and less than 180 degrees in space curved in the shape of trumpet. See General Relativity went beyond the limitations set by Euclid. This was stated by Einstein in his quote.

 

[espen180]

Newton:

Straight from wikipedia: "The essential idea is that coordinates do not exist a priori in nature..."

What does this mean? Or, please explain it for the nonscientist (me).

It means that coordinates are artificial, so physical laws must be independent of the coordinates chosen to represent them. We make sure our equations respect this principle by using inherently geometric quantities, called tensors.

 

[ash64449]

I do not know what angle sum property of triangle means. I'm a graduate student in an English program. I think in language (and yes, I'm aware this is not a good thing when it comes to physics!). Do I believe that two parallel lines will never meet? Good question. If space has no boundaries and nothing affects the motion of these lines, I do not see how they will ever meet, if everything stays constant.

Value of pi also changes!

 

[ash64449]

Nature doesn't have some prescribed coordinate system specially adapted to the laws of physics so why should one coordinate system be any more special than another when writing down the laws of physics?

That is not the thing that quote meant. The answer that i was given is.

 

[WannabeNewton]

That is not the thing that quote meant. The answer that i was given is.

Whatever makes you happy.

 

[ash64449]

Whatever makes you happy.

me happy??

 

[ash64449]

Whatever makes you happy.

In the quote that you gave,it speaks about special theory of relativity. It stated the Principle of relativity. That quote meant General Theory of relativity. In GR,There is no co-ordinate system,just space-time. and the co-ordinate do not have the use of their own!

 

[phinds]

Well i will explain.. These are some limitations of laws of nature such as Euclid's axioms. It states that Angle sum property of triangle is 180 degrees. There is only one straight line passing through two points. These are some limits of law of nature. Albert Einstein said that general relativity goes beyond the law of nature. It does! Energy bends space-time. This curvature is gravity. When space is curved two parallel lines which where parallel is no longer parallel.. Angle sum property of triangle is more than 180 degrees like in surface of Earth and less than 180 degrees in space curved in the shape of trumpet. See General Relativity went beyond the limitations set by Euclid. This was stated by Einstein in his quote.

This is nonsense. Euclid describes math, not the real world. There are locally constrained situations in which Euclid's geometry applies, but to say that you have "gone beyond nature" just because there are physical situations in which it does NOT apply is ridiculous. General relativity does NOT go beyond nature, it DESCRIBES nature and co-incidentally points out the limitation of trying to use Euclid to describe nature.

 

[WannabeNewton]

The point is that we must write down the laws of physics as tensor equations so that they are covariant (more generally we use spinor fields). This respects general covariance.

 

[jartsa]

End of chapter 28.

"The great power possessed by the general principle of relativity lies in the comprehensive limitation which is imposed on the laws of nature..."

The laws of nature must be such that:

1: A machine built jn a still standing factory also works when used in a vehicle moving at any velocity.

2: A machine built in an accelerating spaceship also works on a planet where the acceleration due to gravity is the same as the acceleration of the spaceship was.

 

[ash64449]

This is nonsense. Euclid describes math, not the real world. There are locally constrained situations in which Euclid's geometry applies, but to say that you have "gone beyond nature" just because there are physical situations in which it does NOT apply is ridiculous. General relativity does NOT go beyond nature, it DESCRIBES nature and co-incidentally points out the limitation of trying to use Euclid to describe nature.

don't math describe real world.you have to know that before einsteins,every thing was explained,even physics was explained with the help of euclid's axioms. That is why einstein's general theory of relativity was revolutionary.. Not because it combines many things and all. At that time they went beyond euclid and explain physics based on it..

 

[Mentz114]

don't math describe real world.you have to know that before einsteins,every thing was explained,even physics was explained with the help of euclid's axioms. That is why einstein's general theory of relativity was revolutionary.. Not because it combines many things and all. At that time they went beyond euclid and explain physics based on it..

This is true, but I believe the quote refers to a constraint - and we've had two good candidates proposed above.

 

[ash64449]

This is nonsense. Euclid describes math, not the real world. There are locally constrained situations in which Euclid's geometry applies, but to say that you have "gone beyond nature" just because there are physical situations in which it does NOT apply is ridiculous. General relativity does NOT go beyond nature, it DESCRIBES nature and co-incidentally points out the limitation of trying to use Euclid to describe nature.

if you cannot accept it from my words,then let's einstin's book itself let you this: read the first chapter physical meaning of geometrical propositions. Book is theory of relativity. You will then accept the above which you called nonesense.

 

[ash64449]

This is true, but I believe the quote refers to a constraint - and we've had two good candidates proposed above.

the quote exactly referred to what i said. Read the book that i said.you will understand..

 

[Doc Al]

if you cannot accept it from my words,then let's einstin's book itself let you this: read the first chapter physical meaning of geometrical propositions. Book is theory of relativity. You will then accept the above which you called nonesense.

Sorry, but it is you who have missed the point of the quote. WannabeNewton and phinds are correct.

Think twice before trying to "correct" folks who actually understand relativity.

 

[ash64449]

Sorry, but it is you who have missed the point of the quote. WannabeNewton and phinds are correct.

Think twice before trying to "correct" folks who actually understand relativity.

ok.they are right and i am wrong.

 

[ash64449]

Sorry, but it is you who have missed the point of the quote. WannabeNewton and phinds are correct.

Think twice before trying to "correct" folks who actually understand relativity.

but it is somewhat related to what i said too. Euclid's axioms were treated as laws whose properties depend on space itself. Now with general principle of relativity,einstein proved that it doesn't depend on space itself. I mean laws. There is no such laws.

 

[ash64449]

to understand what i said,you need to look at the first chapter,last paragraph. He talks about faliure of geometrical proposition in general principle of relativity. And what is that these axioms were seen as limits.. He went beyond and said that we can legitimately use any point in curved space to formulate general laws of nature even though it went even beyond the limits of law of nature. This is the connection between what wannabeNewton said and what i said.

 

[Vanadium 50]

This thread has turned into the blind leading the blind. Phinds has answered the question correctly, so there is no need to go off on another tangent. No pun intended.