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Blazinghand
United States25561 Posts
On July 22 2011 06:58 Dagon wrote:Show nested quote +On July 22 2011 06:50 Blazinghand wrote:On July 22 2011 06:38 Dagon wrote:
I am not sure if I undestand this correctly, but if some way of instant comunication is possible (think on the lines of thelepathy), neither twin would notice the other aging faster/slower, right? If instant communication was possible, the laws of physics as we know it would have to be rewritten. Everything we know about Special Relativity would be false. The paradox of the twins would be as irrelevant an idea under that physics as the question of how to cast "expelliarmus" is under current physics. I am definetly not a physicist, but are there no forces that act faster than the speed of light? For example gravity. Does it not manifest itself instantaneous?
I am a physicist. There are no forces that act faster than the speed of light. Gravity does not manifest instantaneously.
http://en.wikipedia.org/wiki/Speed_of_gravity
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On July 22 2011 07:02 Blazinghand wrote:Show nested quote +On July 22 2011 06:58 Dagon wrote:On July 22 2011 06:50 Blazinghand wrote:On July 22 2011 06:38 Dagon wrote:
I am not sure if I undestand this correctly, but if some way of instant comunication is possible (think on the lines of thelepathy), neither twin would notice the other aging faster/slower, right? If instant communication was possible, the laws of physics as we know it would have to be rewritten. Everything we know about Special Relativity would be false. The paradox of the twins would be as irrelevant an idea under that physics as the question of how to cast "expelliarmus" is under current physics. I am definetly not a physicist, but are there no forces that act faster than the speed of light? For example gravity. Does it not manifest itself instantaneous? I am a physicist. There are no forces that act faster than the speed of light. Gravity does not manifest instantaneously. http://en.wikipedia.org/wiki/Speed_of_gravity
Did not know that.
But still.. It says that the speed of gravitational wave is equal to the speed of light in vacuum. So, let's assume the twin in the spaceship has a device witch can detect gravitational pull ( I don't think that's unresonable). And the twin on earth had a device with witch he can create gravitational forces. Wouldn't they still be able to communicate in some kind of morse code, seeing that the messages would be at the speed of light? (so allmost instantaneous in comparison to the velocity of the spaceship)
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On July 22 2011 07:19 Dagon wrote:Show nested quote +On July 22 2011 07:02 Blazinghand wrote:On July 22 2011 06:58 Dagon wrote:On July 22 2011 06:50 Blazinghand wrote:On July 22 2011 06:38 Dagon wrote:
I am not sure if I undestand this correctly, but if some way of instant comunication is possible (think on the lines of thelepathy), neither twin would notice the other aging faster/slower, right? If instant communication was possible, the laws of physics as we know it would have to be rewritten. Everything we know about Special Relativity would be false. The paradox of the twins would be as irrelevant an idea under that physics as the question of how to cast "expelliarmus" is under current physics. I am definetly not a physicist, but are there no forces that act faster than the speed of light? For example gravity. Does it not manifest itself instantaneous? I am a physicist. There are no forces that act faster than the speed of light. Gravity does not manifest instantaneously. http://en.wikipedia.org/wiki/Speed_of_gravity Did not know that. But still.. It says that the speed of gravitational wave is equal to the speed of light in vacuum. So, let's assume the twin in the spaceship has a device witch can detect gravitational pull ( I don't think that's unresonable). And the twin on earth had a device with witch he can create gravitational forces. Wouldn't they still be able to communicate in some kind of morse code, seeing that the messages would be at the speed of light? (so allmost instantaneous in comparison to the velocity of the spaceship)
Nope, in the experiment the ship is moving close to the speed of light for the effects to be noticeable. Also you are complicating things, you can just use radio waves to communicate as they move at the speed of light  No need to use gravity
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Blazinghand
United States25561 Posts
On July 22 2011 07:19 Dagon wrote:Show nested quote +On July 22 2011 07:02 Blazinghand wrote:On July 22 2011 06:58 Dagon wrote:On July 22 2011 06:50 Blazinghand wrote:On July 22 2011 06:38 Dagon wrote:
I am not sure if I undestand this correctly, but if some way of instant comunication is possible (think on the lines of thelepathy), neither twin would notice the other aging faster/slower, right? If instant communication was possible, the laws of physics as we know it would have to be rewritten. Everything we know about Special Relativity would be false. The paradox of the twins would be as irrelevant an idea under that physics as the question of how to cast "expelliarmus" is under current physics. I am definetly not a physicist, but are there no forces that act faster than the speed of light? For example gravity. Does it not manifest itself instantaneous? I am a physicist. There are no forces that act faster than the speed of light. Gravity does not manifest instantaneously. http://en.wikipedia.org/wiki/Speed_of_gravity Did not know that. But still.. It says that the speed of gravitational wave is equal to the speed of light in vacuum. So, let's assume the twin in the spaceship has a device witch can detect gravitational pull ( I don't think that's unresonable). And the twin on earth had a device with witch he can create gravitational forces. Wouldn't they still be able to communicate in some kind of morse code, seeing that the messages would be at the speed of light? (so allmost instantaneous in comparison to the velocity of the spaceship)
Um, yes, but not any better than if they used lasers or radios, which also travel at the speed of light. Also, remember we're talking about a situation where you can travel at >.99c. They could as easily communicate by writing letters and strapping them onto rockets.
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Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end.
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Blazinghand
United States25561 Posts
On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end.
You don't have to reach the end of the world to know that it's not flat. In the 5th century BC scholars knew the earth was round.
http://en.wikipedia.org/wiki/Eratosthenes#Eratosthenes.27_measurement_of_the_Earth.27s_circumference
You know why? Because you can use evidence to find the truth. Science doesn't make assumptions it draws conclusions.
We used to think that some things were faster than the speed of light, or that the concept of "instantaneous" existed. We were wrong. We learned. We used evidence. It's not a premise, it's a conclusion.
edited for typos
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On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end.
It is actually one of the better "proven" things in science. But as always in science no absolutes and no proofs, just evidence and testing theories.
EDIT: especially since even I can generate at home things moving at relativistic speeds
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On July 22 2011 07:41 mcc wrote:Show nested quote +On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end. It is actually one of the better "proven" things in science. But as always in science no absolutes and no proofs, just evidence and testing theories. EDIT: especially since even I can generate at home things moving at relativistic speeds
High five for being a world class fart artist!
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On July 22 2011 07:38 Blazinghand wrote:Show nested quote +On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end. You don't have to reach the end of the world to know that it's not flat. In the 5th century BC scholars knew the earth was round. http://en.wikipedia.org/wiki/Eratosthenes#Eratosthenes.27_measurement_of_the_Earth.27s_circumferenceYou know why? Because you can use evidence to find the truth. Science doesn't make assumptions it draws conclusions. We used to think that some things were faster than the speed of light, or that the concept of "instantaneous" existed. We were wrong. We learned. We used evidence. It's not a premise, it's a conclusion. edited for typos
You say that, but dosen't modern physics atribute every universal law to a not yet understood probabilistic table? That's what quantum physics was all about, wasn't it? Also the string theory. It can certanly explain gravity at a quantum level, but can not be proven in the least. (or disproven for that matter)
Premises are made in physics. There are not only conclusions.
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On July 22 2011 07:57 Dagon wrote:Show nested quote +On July 22 2011 07:38 Blazinghand wrote:On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end. You don't have to reach the end of the world to know that it's not flat. In the 5th century BC scholars knew the earth was round. http://en.wikipedia.org/wiki/Eratosthenes#Eratosthenes.27_measurement_of_the_Earth.27s_circumferenceYou know why? Because you can use evidence to find the truth. Science doesn't make assumptions it draws conclusions. We used to think that some things were faster than the speed of light, or that the concept of "instantaneous" existed. We were wrong. We learned. We used evidence. It's not a premise, it's a conclusion. edited for typos You say that, but dosen't modern physics atribute every universal law to a not yet understood probabilistic table? That's what quantum physics was all about, wasn't it? Also the string theory. It can certanly explain gravity at a quantum level, but can not be proven in the least. (or disproven for that matter) Premises are made in physics. There are not only conclusions.
string theories and the corresponding n-dimensional realities they presuppose are a little bit different than the 4-dimensional space-time of einstein's relativity when it comes to confidence in its axioms.
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Blazinghand
United States25561 Posts
On July 22 2011 07:57 Dagon wrote:Show nested quote +On July 22 2011 07:38 Blazinghand wrote:On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end. You don't have to reach the end of the world to know that it's not flat. In the 5th century BC scholars knew the earth was round. http://en.wikipedia.org/wiki/Eratosthenes#Eratosthenes.27_measurement_of_the_Earth.27s_circumferenceYou know why? Because you can use evidence to find the truth. Science doesn't make assumptions it draws conclusions. We used to think that some things were faster than the speed of light, or that the concept of "instantaneous" existed. We were wrong. We learned. We used evidence. It's not a premise, it's a conclusion. edited for typos You say that, but dosen't modern physics atribute every universal law to a not yet understood probabilistic table? That's what quantum physics was all about, wasn't it? Also the string theory. It can certanly explain gravity at a quantum level, but can not be proven in the least. (or disproven for that matter) Premises are made in physics. There are not only conclusions.
Nope. You don't "attribute" laws and theories to anything. They're just patterns that have been observed. And if there is new data that changes the way those patterns work, it is evaluated, reproduced, and factored into the model.
Are you arguing that there's no gravity? I mean, as far as theories as to WHY gravity works, those are still in progress. The theories as to HOW/WHAT gravity does are pretty well fleshed out. Which of these are you questioning?
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The premise for General Relativity though is not that the speed of light is the upper limit, but that light always travels at a constant speed, regardless of the reference you are using (ie while standing still or in a 0.99c moving spaceship, you can see your face in the mirror in both scenarios). An imaginary-mass particle like the tachion resides on the other end of the plot, where the speed of light is the lower limit.
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On July 22 2011 07:41 mcc wrote:Show nested quote +On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end. It is actually one of the better "proven" things in science. But as always in science no absolutes and no proofs, just evidence and testing theories. EDIT: especially since even I can generate at home things moving at relativistic speeds
Exactly. Science works the way that you make a theory that explains all data that is known up to that point. If it is a good theory, you can usually deduct some other things from that (If you can't, it is a useless theory). Then, you think up experiments to check whether those things are actually the way they should be according to your theory. If they are, they strengthen your theory. If they are not, you need a new theory.
In the case of special relativity, as far as i know Einstein basically thought about "what if the speed of light is constant in all inertial system?" (Inertial System = any nonaccelerated system, but the velocity of the system can be whatever). If you go from that basic premisse, everything else in special relativity like time delation, length contraction, mass distortion and the idea that nothing can be faster then the speed of light directly follows. So far, any experiment made is absolutely in line with those predictions, and as a result this idea is generally acceoted as correct. However, it is not dogma, so if someone comes up with an experiment that follows the scientific guidelines of reproducability and is contrary to that theory, it will have to be changed.But so far that has not happened. In contrary, every single experiment continues to deliver exactly the data that is expected in special relativity.
Here are some experiments which strengthen the theory of special relativity:
http://en.wikipedia.org/wiki/Tests_of_special_relativity
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On July 22 2011 08:05 Blazinghand wrote:Show nested quote +On July 22 2011 07:57 Dagon wrote:On July 22 2011 07:38 Blazinghand wrote:On July 22 2011 07:35 Dagon wrote:
Hmm.. I do have one question though. Isn't all this just speculation based on some premises? Has it actually been proven that the speed of light is the fastest interaction in the universe? Because the whole theory of relativity is based on this premise.
This whole paradox sounds to me the same as asking yourself in 200 AD: "what happens when you reach the end of the world?". And trying to answer this question basing your judgement on the "at the time" logical ideea that the earth is flat and has an end. You don't have to reach the end of the world to know that it's not flat. In the 5th century BC scholars knew the earth was round. http://en.wikipedia.org/wiki/Eratosthenes#Eratosthenes.27_measurement_of_the_Earth.27s_circumferenceYou know why? Because you can use evidence to find the truth. Science doesn't make assumptions it draws conclusions. We used to think that some things were faster than the speed of light, or that the concept of "instantaneous" existed. We were wrong. We learned. We used evidence. It's not a premise, it's a conclusion. edited for typos You say that, but dosen't modern physics atribute every universal law to a not yet understood probabilistic table? That's what quantum physics was all about, wasn't it? Also the string theory. It can certanly explain gravity at a quantum level, but can not be proven in the least. (or disproven for that matter) Premises are made in physics. There are not only conclusions. Nope. You don't "attribute" laws and theories to anything. They're just patterns that have been observed. And if there is new data that changes the way those patterns work, it is evaluated, reproduced, and factored into the model. Are you arguing that there's no gravity? I mean, as far as theories as to WHY gravity works, those are still in progress. The theories as to HOW/WHAT gravity does are pretty well fleshed out. Which of these are you questioning?
I support this. To go even further, science does fundamentally not answer "why?" questions. That is a common misconception. Science only tries to interpretate HOW stuff works, and thus to predict what will happen under specific circumstances without actually having to observe those specific conditions beforehand. A good scientific theory will deliver predictions for a lot of things by trying to generalise specific data. All the "whys" are just helpful constructs, and don't necessarily need to have direct scientific reality. No matter where you start, if you ask "why" often enough, you will reach a point where you won't get an answer. The reason is not that you don't have enough science to get that answer, you will always reach that point at some time. Because those answers to why-question that you think science delivers are not actually what you think they are, they are just part of a theory that explains hows, and not actual whys.
But that is not a flaw in science. Science is not supposed to tell you why something happens, it is supposed to determine how it happens. Which is all that is necessary. "Why" is not a question that needs to be answered for anything other than ease of mind.
If you want answers to whys, you will need to look somewhere else, but those are generally only speculation anyways, no matter if they come from religion or philosophy.
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I am so in love with this thread. We should do a monthly science discussion thread!
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Nawyria you should post some links where I can read more about similar experiments/concepts. Specifically I am in love with the space-time ideas, for example I remember reading about how space isn't linear and traveling in one direction doesn't necessarily mean you are traveling straight if your journey was graphed.
Though I'd like to read something that doesn't require me to be a physicist to understand
also ps: thanks for your explanations throughout the thread
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On July 22 2011 09:52 Nawyria wrote:
I am so in love with this thread. We should do a monthly science discussion thread!
Seconded. This is a pretty interesting discussion.
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Nawyria, answer this. I'm no physicist, but I'm thinking there might be a flaw in the following claim:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
?
Ty
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On July 22 2011 06:06 Nawyria wrote:Show nested quote +On July 22 2011 05:53 ]343[ wrote:On July 22 2011 05:18 Nawyria wrote:On July 22 2011 05:06 Sabin010 wrote:
The real question is what if the twins kept in contact via morse code through entagled particles? If twin A measures his entangled particle on one end, he knows the wavefunction of twin B's particle on the other hand. However, when twin B measured the particle on his end, he has no way of knowing whether the result he gets came from a wavefunction that collapsed because twin A measured the other particle. Entangled particles cannot actually transmit information. WHOA thanks I was wondering about this! But enough pairs of entangled particles could transmit information with high probability, no? The "information" transmitted is the wavefunction of the particles, which determines the probability with which a particular result will be found when measured. So in this way measuring the particle on one side impacts the measurement on the other side. However, there is no way of telling whether a measurement was conducted on one side, so you can never tell if the outcome of a particular measurement was due to random chance, or due to the collapse of a wavefunction.
Dumb question: How are entangled particles going to be more useful than just giving two people pieces of paper saying "YES" and "NO". Then when each of them look at their paper they know what the other one got.
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+ Show Spoiler +On July 23 2011 01:33 arbitrageur wrote:
A real n body system, in any possible configuration, can maintain orbit until t->infinite without the system collapsing on itself or the planets going out into space.
If two objects orbit each other with zero eccentricity (circles), and both bodies are tidally locked to the other, then they can remain exactly as they are for t->infinity.
+ Show Spoiler +On July 23 2011 01:33 arbitrageur wrote:
Say there's water on one. You could put an electricity generator in this water, and as the gravity of other bodies pulls and pushes on the water it will move through the turbine and electricity will be generated. As t->infinite and the system does not collapse, you gather infinite energy with a finite amount of matter (i.e. a never-ending supply of energy).
If the bodies rotate relative to one another, or the orbits are eccentric, then an oceanic tide is possible. Friction will dissipate this motion, as will a generator running off the shifting of water. This will gradually change the orbits, removing the relative rotation between the objects, and transferring that angular momentum of rotation into orbital angular momentum. This would increase or decrease orbital radius, depending on whether the relative rotation was in the prograde or retrograde direction.
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EPT
