Light Speed (and faster...)

[big_pappa_smurf]

Just curious, but why does everyone assume that faster-than-light travel is impossible (or very highly improbable):?: Consider:
Einsteins theory is based on what he knew then.
Newton, Galileio and Plato also had theories based on what they knew then. Most of those theories have rather severe holes in them, why does everyone assume that Einstein is right
If you had asked someone 500 years ago about travelling faster than the speed of sound then they would probably say it was impossible.
In 500 years time, maybe someone will have proven Einstein wrong.

[Keiji]

Deleted your useless poll.

As for the actual subject, it is impossible to travel faster than light because g gets higher as you speed up, which has been proven. G affects your acceleration, so the closer you get to light speed, the more force you must put in to accelerate. At light speed, g is so high that it would take an infinite force to accelerate. So that is why it is impossible.

[Aale de Winkel]

Proofs can only exist, as far as the current theory allows. Perhaps only mathematical proofs are thus rigid that falsification isn't possible. But within physics no such absooluteness.
But according to current physics, faster then light travel is impossible. But perhaps some Cochrane comes along to invent travel at warp higher then 1.0.
Currently though we are limited to Einsteintonian physics, and do think traveling toward the stars must be achieved by some other means.

[houserichichi]

why does everyone assume that Einstein is right

We know he's not entirely right since relativity doesn't work properly with quantum mechanics. Obviously one, if not both of these theories has to be fiddled with to properly finish the jigsaw puzzle they call physics. Now whether relativity is just an approximation to some newer theory that someone will discover down the road, I can't say. But Einstein just elaborated on Newton's ideas and took them an extra step...so Newton wasn't wrong, he just wasn't 100% right. Same goes for Einstein, I suspect - but until we know what the next "right" theory is, there's no reason to throw his concepts and results out the window. Experimental science is the verification of the theory...and so far Einstein has held up pretty darn good, I'd say.

In 500 years time, maybe someone will have proven Einstein wrong.

I hope it's sooner than that...I wouldn't mind being the one to do it either. Till then we have to assume that nothing can travel faster than light - go with what works until you can prove it otherwise. Making claims about something that you can't back up isn't science - it's improper.

[Gilles]

Einstein wasn't wrong, but neither are you guys.

He said that we can't travel faster then light. Well, he's right there. But far away from the earth, light travels with a different speed. At an infinite distance from mass, it even travels with an infinite speed (time depends on mass, ask einstein). That means we can travel faster then 300 000 km/second, wich we call the speed of light, but thats just seen from the earth. It's called the relativity theory, remember.
Once you travel with a speed close to that of light, your mass will increase, wich makes time go slower. That means that you go faster. duh...

[jinydu]

Einstein wasn't wrong, but neither are you guys.

He said that we can't travel faster then light. Well, he's right there. But far away from the earth, light travels with a different speed. At an infinite distance from mass, it even travels with an infinite speed (time depends on mass, ask einstein). That means we can travel faster then 300 000 km/second, wich we call the speed of light, but thats just seen from the earth. It's called the relativity theory, remember.
Once you travel with a speed close to that of light, your mass will increase, wich makes time go slower. That means that you go faster. duh...

It is a fundamental postulate of Relativity that the speed of light is always constant, at every place and time in the universe, for every observer. In fact, Special Relativity doesn't even require planets to exist.

See my post on the other thread.

[PWrong]

Just curious, but why does everyone assume that faster-than-light travel is impossible (or very highly improbable):?: Consider:
Einsteins theory is based on what he knew then.

Well, your theory is that Einstein was wrong, and is based on what you know now. What Einstein knew then, about maths and physics, is a lot more than either you or I know. General Relativity is based on very complicated mathematics. There are people who understand it just as well as Einstein did, and they haven't found any flaws in it.

So you can't really prove it wrong, or claim that it's wrong simply because one day someone might prove it wrong. Very few things get proved wrong in physics.

Newton, Galileio and Plato also had theories based on what they knew then. Most of those theories have rather severe holes in them, why does everyone assume that Einstein is right

Again, even what Newton knew is more than the average person knows now. You're talking about the inventor of calculus! Anyway, they didn't have holes in them, they filled up the holes left by ordinary people.

Before Galileo, everyone assumed we were the centre of the universe. Before Newton, everyone assumed that planets simply flew around of their own accord. And before Einstein, everyone assumed that you could travel as fast as you like.

It takes a lot of evidence to break assumptions like these. Even now, people simply assume that light is just a technological barrier.

[3l3ctr0]

i wouldnt say that travaling faster then the speed of light is imposible but say if you get to the speed the extream Gs would crush any liveing thing. so there is actualy no point of travaling at thoes speeds....

but plz correct me if you think im wrong...

[jinydu]

i wouldnt say that travaling faster then the speed of light is imposible but say if you get to the speed the extream Gs would crush any liveing thing. so there is actualy no point of travaling at thoes speeds....

but plz correct me if you think im wrong...

If you read my earlier posts, you'll see that I've written numerous arguments for why it is impossible to travel faster than the speed of light. It is a limit imposed by the laws of nature, not by technological limits.

Furthermore, travelling close to the speed of light would not lead to extreme G's. If it did, it would be possible for you to detect that you were travelling at close to the speed of light. This violates the Principle of Relativity:

http://www2.slac.stanford.edu/vvc/theor ... ivity.html

[zoralink]

I see what you mean with the crushing, I know what you are talking about.

[3l3ctr0]

zoralink lol ur just puting in things so u can bring up yr posts am i wrong lol

[zoralink]

no, I am not, I was trying to become aquainted with people who share an interest in such subjects as that I have found recently in this forum. That assumption was not cool, but the fact you posted speciafically to make such an accusation was not in the least bit better.

The previous short response was just to stifle the constant and redundant expression of the "crushing" thought I heard upon reading this thread. I remember so little of it now since I made the post long ago and barely remember the topic, which might also signify your most recent response is the first in a long dry spell here.

Forgive me for trying to enter the circle of this discussion with my thoughts.

[solodeath]

why do u want to move faster then light? you would be dead.... and even if there were some "way" for you to move at that speed, then think about how much energy u need. besize there are other ways to move from point A to point B.

btw you can move faster then the speed of light in different envirment. easy proof of this is if a radioactive fuel rod from a nuclear reactor is immersed in deep water. the e- would would move faster then the speed of light in water.

[jinydu]

why do u want to move faster then light? you would be dead.... and even if there were some "way" for you to move at that speed, then think about how much energy u need. besize there are other ways to move from point A to point B.

btw you can move faster then the speed of light in different envirment. easy proof of this is if a radioactive fuel rod from a nuclear reactor is immersed in deep water. the e- would would move faster then the speed of light in water.

Yup, its called Cerenkov Radiation:

http://scienceworld.wolfram.com/physics ... ation.html

However, while you can travel faster than light in a medium where the speed of light is lower than it is in the vacuum, you can't travel faster than the speed of light in a vacuum.

[brasileiro]

I have something to point out. Being as these theories we speak of are just that... theories, I have one of my own. Since G force is proven to increase with speed... it is only for on earth. True though, that you need more force to move faster in space, it does not, as far as we know, take even more force to increase speed because there is leterally nothing holding you back. PLUS, the fact that we have not gotten anywhere close to light speed, it is impossible to comprehend what goes on. My theory is that since you are almost travelling at "maximum velocity", increasing speed may become easier. I will attempt to explain. Objects that can hold together travelling at light speed have a molecular structure of which is also travelling at light speed... so, in turn, they can pass through solid mass. Which means that travelling closer to light speed will reduce the mass able to hold you back, if there is any out there in space, and also reduces the amount of force required to increase velocity. Now, I'm fairly new at this whole relativity thing, but these are my own thoughts, based on reading this forum. Please enlighten me and give your input on this matter.

Come to think of it, there is something that "travels" (if you want to call it's 'being' "travelling") faster than light. It's the black hole. IF there is nothing that travels faster than light, theoretically, then how do you account for Black Holes? I mean, light can't escape them, no matter how fast light seems to be... it's trapped. The matter trapped in the black hole travels faster than the speed of light. Once again, enlighten me.

[jinydu]

According to Special Relativity, if an observer in an inertial frame of reference observes an object travelling at very high speeds, the object's inertia (resistance towards acceleration) will approach infinity as its speed approaches the speed of light. This is not just vague, philosophical speculation. Special Relativity provides a precise, quantitative description of what happens, and its predictions have been tested experimentally numerous times. In today's particle accelerators, particles are routinely accelerated to speeds of over 99% the speed of light, and measurements are fully in accordance with the predictions of relativity.

Also, black holes do not travel faster than the speed of light. Light escapes cannot escape a black hole ---> Black holes travel faster than light. That's definitely a non-sequiter. Light cannot escape because the gravitational field is too strong, not because the black hole is travelling too fast.

[brasileiro]

According to Special Relativity, if an observer in an inertial frame of reference observes an object travelling at very high speeds, the object's inertia (resistance towards acceleration) will approach infinity as its speed approaches the speed of light. This is not just vague, philosophical speculation. Special Relativity provides a precise, quantitative description of what happens, and its predictions have been tested experimentally numerous times. In today's particle accelerators, particles are routinely accelerated to speeds of over 99% the speed of light, and measurements are fully in accordance with the predictions of relativity.

Also, black holes do not travel faster than the speed of light. Light escapes cannot escape a black hole ---> Black holes travel faster than light. That's definitely a non-sequiter. Light cannot escape because the gravitational field is too strong, not because the black hole is travelling too fast.

That may be true... on earth. The thing is, none of our particle accellerators are located in space. That's the thing. If space is what we perceive it as, a vacuum, then that means there is nothing to hold us back from accellerating faster, with much less effort. No matter how much of a vacuum we develope here on earth, it will never compare to space. And, the problem with THIS theory, is that even though space is perceived as a vacuum, there is no true vacuum... like I think I stated before. Let alone it's the black hole, which sucks up what we believe to be the "ultimate vacuum," space. Now this brings this thought to mind... if there is something with enough gravitational pull to suck up a vacuum, is there another "thing" that has even more? Since our universe is so full of suprises, it is quite possible for this to happen. In which case, we would be getting sucked up as we speak... and that would explain the rotating/moving universe.. which is ever-expanding.... we would be getting sucked up in several directions... which also has it's flaws... but what theory doesn't? I mean, if they were proven to be 100% correct, then there would be no reason to continue to call them "theories"... would there?

[Twix18]

[/quote]Since our universe is so full of suprises, it is quite possible for this to happen. In which case, we would be getting sucked up as we speak... and that would explain the rotating/moving universe.. which is ever-expanding.... we would be getting sucked up in several directions... which also has it's flaws... but what theory doesn't? I mean, if they were proven to be 100% correct, then there would be no reason to continue to call them "theories"... would there?[/quote]

agreed, but there is something troubling me, nature abhores a vacume correct? so if we have a black hole, that is taking in light... then does light have presense in our demension? and if it does and this black hole take in not only light but everything else than isnt this vacume being filled...? assuming yes... where is all the energy and mass of stars and plantes going?

i have a different universal creation theory for you. lets say that we are the bi product of a filled black hole. how would we know differently from what we do now?

[jinydu]

Ah, the infamous confusion of the word "theory". In science, a "theory" is a systematic framework for explaining natural phenomenon that has been tested again and again, and been found to to consistently agree with many different experiments. This is in sharp contrast to the everyday meaning of the word "theory", meaning hunch. By definition, scientific theories are well-established and merit a high degree of confidence. If one isn't, then it shouldn't be called a theory (and usually isn't).

Furthermore, it is not true that modern particle accelerators cannot match the vacuum of space. Major particle accelerators, like the ones at Fermilab and CERN cost many millions of dollars and are planned, built and maintained to very high standards. It is practical to build a very good vacuum, so long as you have enough funding.

Furthermore, and more fundamentally, the reason matter cannot accelerate to the speed of light is not because there is some medium "holding it back". Instead, it is because the object's inertia is approaching infinity. In short, the speed of light barrier is a fundamental property of the universe, not some property of air.

I would recommend taking a look at some serious relativity websites online, or much better yet, taking a course in relativity, if you really want to understand it correctly.

[brasileiro]

Which is all I am saying... theory is found consistant... but until proven 100%, it is only a theory... and they all start from hunches... so aren't they still a hunch? You can only improve a theory from ideas.. it is, in escence, one ongoing hunch... but like you said, people do confuse the word "theory" today... it is taken that anyone can have their own theories... and I apologize if I got caught up in today's usage of the term

[brasileiro]

I also apologize for the mistaken message I was coming across with about the black holes "travelling". I was trying to concentrate more on the matter being sucked into it... more-so than the hole itself. I just lost my train of thought int he middle of it and moved on...

[jinydu]

As commonly understood, a "hunch" is a belief with little evidence behind it. If you are very sure that something is correct/reliable, you don't generally call it a hunch.

Of course, a scientific theory can never be proved 100%. But if it has been tested through numerous experiments by generations of scientists, and the experiments have agreed with the theory on virtually every occasion, you can have high confidence in the correctness of the theory, at least in the areas where it has been tested.

Generally, there are two main ways that theories are improved: 1) New ideas, 2) An experiment contradicting the theory, which forces the theory to be thrown away or (more commonly) revised.

[AlienBilly]

A common mistake is that people missread the theory of relativity in lack of understanding or thoughts based on a simplifyed version of the universe, and so they say that the theory of relativity says that nothing can travel faster then the speed of light.
That's not what it says.
What it does say is that nothing can accelerate past the speed of light, because any object that would try to accelerate to the speed of light would need infinate energy to reach the speed of light, and if it would it would have an infine mass and a zero sized volume (Lorentz-transformation), and also get stuck there traveling at the speed of time if you so will..
However, when you travel at around 70% of the speed of light, because of the relative motion, the map around you shrinks so that to the relativly resting observer you would already be traveling at the speed of light.
And any higher speed you would be traveling over the speed of light in relatvity to the observer, atleast according to my understanding of the theory.
There are also a particle called tachyon which is belived to be UNABLE
to travel UNDER the speed of light, and it's excistance I belive have just
been prooven, should that be the case, it might explain quantum mechanical corrilation wich defenitly acts instantaniously, but not nessesarly faster then the speed of light (wormhole theory).

Now I'm off to watch the simpssons

[bo198214]

A common mistake is that people missread the theory of relativity in lack of understanding or thoughts based on a simplifyed version of the universe, and so they say that the theory of relativity says that nothing can travel faster then the speed of light.
That's not what it says.

That depends what is "the" theory of relativity. At least a very common statement of physicists is that information can not conveyed faster than light. Though I didnt realize that information was the subject of physics. I dont remember exactly, but if it would be possible then a future event could influence a past event and so causality would be discarded.

However, when you travel at around 70% of the speed of light, because of the relative motion, the map around you shrinks so that to the relativly resting observer you would already be traveling at the speed of light. ... , atleast according to my understanding of the theory.

It seems that *your* understanding of realtivity theory isnt correct either. Or can you explain your statement a bit more in detail?

There are also a particle called tachyon which is belived to be UNABLE to travel UNDER the speed of light

Tachyon theory (at least) contradicts the relativity theory (this topic was mentioned in some other thread here ....) so Tachyons are no example for relativstic possibilities.

[AlienBilly]

It seems that *your* understanding of realtivity theory isnt correct either. Or can you explain your statement a bit more in detail?

If you travel in 70% of the speed of light, the mass and time dillation will be such as you relativly will have coverd the distance that without relativity would have requierd the speed of light.

This is beacuse as faster you go the more your time slows down.

Or is this not correct ?

[bo198214]

If you travel in 70% of the speed of light, the mass and time dillation will be such as you relativly will have coverd the distance that without relativity would have requierd the speed of light.

You dont use the 70% in your computation. So I would assume that it should be true for every %. And especially for 0% - when you are still. So your argumentations seems contradictive to me.

[moonlord]

As many have said, a theory (scientific) cannot be proven right no matter how many experiments agree with it.

Back to the subject, the TR implies clearly that the speed of light is unreachable for any entity with mass. You may consider the TR wrong, but you need proof to do so. Come with a better theory, prove it and it's ok.

That may be true... on earth.

It is a postulate of physics that the laws valid here are valid anywhere. It's like the Euclidean geometry. No one knows if it's correct, but that doesn't stop us from using it daily.

[Batman3]

IF the world were Newtonian, I once calculated that at the acceleration due to Earth gravity, it would take 1 year to accelerate to .5c . Coasting and decelerating the whole trip would take to alpha centauri 5.3 years=2*1+3.3 years. One might need rad shielding.

Maybe info re a function of speed versus rads versus human half-life is available. I mean, to see how far one could get before burning out at the greatest viable acceleration and speed(w/no shielding from rads).

[Batman3]

Is this history and experiment correct?

The Michelson-Morley experiment established that the experiment(stationary w/respect to the Earth) was not moving with respect to the ether. This was because there was observed no interference in the light waves moving in 2 perpendicular directions. Thus the experiment(and so the Earth) were not moving with respect to the ether. The TruthAuthority had declared that the earth was not to be considered the center of the universe(that was old news), but nevertheless, the Law was the same eveywhere and so the ether moved in concert with itself everywhere and so since you may not have a contradiction, there was no ether.
The electromagnetic eq'ns however in this case predict that the speed of light =c(i.e. everywhere implied by the Law) and so Relativity was True and so the lorentz transformations were Declared True and Observed. (Because to be consistent with the expermient and Law).
Thus we have real evidence(Maxwell's eq'ns and the Michelson Morley exp't) and a Law that give us Relativity.

Various attempts were made to wiggle out--Particle physics, QM, WaveMechanics, String Theory, but they involved impossible difficulties. The TruthAuthority had won the day. (Note:Relativity was not accepted for years by physicists even after Einstein proposed it and he got the NOble prize for blackbody radiation theory instead.)

I will admit that I have seen a hydrogen spectrum in the lab, though I cannot explain that from an intellectual perspective.) Intellectualy, it looks like a lie, but visually there it is. Wherever there is.
---------------------------------
---------------------------------
A way out of the above mess might have been to say that there was something wrong with the above Law in that the ether moves at the velocity vector of the planet whose ether it is in.

Earth's ether moves with Earth; Mars' ether moves with Mars and the interstellar ether moves with the sun. The speed of light in each medium is c wrt that medium.


-----
Note on my personal agenda: I like to think that QM is wrong because it does not provide for moral judgement within itself. QM is about bound states and hence about TruthAuthorities so sources which subscribe to the QMTA are suspect. Including my eyes.

[jinydu]

Well, no physicist that I know has ever used the term TruthAuthority. But the Michelson-Morley experiment, and all subsequent experiments, did indeed fail to detect evidence of an ether. My current physics professor says that he uses special relativity in his research every day and has no found no contradictions.