Faster than light travel proved sort off

[HallsofIvy]

So I was right all along and you guys just confused me with your charts. ;)

Since the previous post flatly contradicted what you were saying, how do you arrive at "I was right all along"?

 

[mark_gg]

I read the relativistic rocket FAQ carefully as well as email a lecturer in my university and it is indeed possible to travel to a point in space a light year away in less then a year. What I didn't know was that space would 'bend' towards you making this possible.

The person who replied about the speed limit of a sports car is incorrect, because as I kept emphasizing 'speed' is essentially an arbitrary measure we use only when related to other bodies.e.g. how fast are you really driving at? well in regards to the surface of the Earth, maybe around 100KPH, but what about the Sun? then it becomes tens of thousands... what about the Andromeda galaxy etc... it can become millions.

As the univserse has no ether, it lacks any reference points... meaning there is no limit to acceleration.

Im amazed at some of the inept answers I was getting.. until the physics experts had to jump in and tell me I was half right.

 

[mark_gg]

to those who want to jump in and tell me that I'm wrong, please read the entire thread first. I'm quite proud of myself for thinking this up at 3am in bed one night.

Einstein when he said you need infinite energy was proposing a hypothetical situation. Of course you are never really traveling faster then light, but space literally shrinks instead.

But it is theoretically possible to go any speed you like (well more accurately, to get to a point that appears more then a light year in relation to say Earth, in less then a year). Orson Scott Card in his book Ender's Game understood this when talking about interstellar space travel.

 

[Mordred]

Unfortunately your still not getting it. Realivity deals with 4 dimensions the 3 spatial + time. when they say you can each the centre of the galaxy in 12 years this is because the space-time shrinks and time slows down for the passengers on board the ship HOWEVER for someone on Earth that person will not arrive for another 3000 years. IN other words it becomes a one way trip by the time he returns everyone he ever knew would be long dead. For NASA to dso this expereiment you want them to do they would never get the results back as its highly doubtful NASA will exist. Also the reason you cannot cross light speed has been shown in the colliders when you approach 99.9% of light speed any mass particle will start gaining mass by the formula E=Mc2. The extra energy used to accelerate that object faster will start to convert into additional mass hence infinite energy neded to reach light speed. Yes we can utilize the time dilation effects to travel farther than what light speed restrictions allow but that is not an increase of speed but due to changes within spacetime itself and effectively means it does you little to know good. From all reference frames anyone measuring the speed of that ship will measure it at 99.997% of light speed (only massless object can actually reach light speed.) This is not to say some things do not travel faster than the speed of light as per say it is a cosmological constant light has been slowed down and there has been some tests that have shown experimentally that by altering frequencies of the light ther are cases where they are slightly faster however these experiments are not widely accepted as the are difficult to replicate and may be a case of inaccuracies in measurement.. If you search the internet you sometimes come across those articles. Tachyon particle for example is only a particle that has been theorized mathematically that does not infer that it is proven. One of the problems is that if you were in fact traveling faster than the speed of light you would be going backward in time this violates causality where where an event occurs before before the cause of that event. Not to mention the grandfather paradox. Now like yourself I am not a physicist however I have taken the time to understand what general relativity means and yes it gets confusing, yes I wish it were different but that is proven beyond a shadow of a doubt by more experiments than you can imagine.
One classic experiment was two atomic clocks both matched up to each other. One was flown around the workd at high speed. One kept at rest on Earth and yes the one that flew around the world was behind the one at rest upon return. PROVEN
The warpage of space is proven by measuring stars behind the sun during an eclipse ( so they could see the stars with the amount of light the sun generates and the General relavitiy model was again PROVEN.
The colliders used to move a quantum particle at near light speed if you were correct would be able to move that particle faster than light, I have no doubt they tried amd failed to do so, so again its PROVEN.
A theory does not become a law until that theory is proven all the laws or just that they are fundamental laws no longer theoretical but PROVEN.

 

[mark_gg]

Unfortunately your still not getting it. Realivity deals with 4 dimensions the 3 spatial + time. when they say you can each the centre of the galaxy in 12 years this is because the space-time shrinks and time slows down for the passengers on board the ship HOWEVER for someone on Earth that person will not arrive for another 3000 years. IN other words it becomes a one way trip by the time he returns everyone he ever knew would be long dead. For NASA to dso this expereiment you want them to do they would never get the results back as its highly doubtful NASA will exist. Also the reason you cannot cross light speed has been shown in the colliders when you approach 99.9% of light speed any mass particle will start gaining mass by the formula E=Mc2. The extra energy used to accelerate that object faster will start to convert into additional mass hence infinite energy neded to reach light speed. Yes we can utilize the time dilation effects to travel farther than what light speed restrictions allow but that is not an increase of speed but due to changes within spacetime itself and effectively means it does you little to know good.

Im aware that for observers on Earth the ship can never pass light speed, but I am talking about the crew on the ship... which for them means they CAN travel faster than light, and reach a light year in distance, in less then a year. Maybe re read the thread from the beginning.

Of course it does good. It means you can send out young people to far away planets, and they will still be alive when they get there (although their friends on Earth have died of old age). No need for cryofreezing at all.

 

[mark_gg]

sorry to clarify... length contraction allows this to occur, so they are not traveling ftl per se.

I think you will find this is all true, and been verified by others. People need to get the concept that speed is a arbitrary measurement when it comes to the Universe.

 

[darkhorror]

This has been brought up many times. But distance speed and time all depend on frames of reference. All you are doing is mixing frames of reference so you get faster than light. When if fact in no frame of reference you are going faster than light.

 

[mark_gg]

This has been brought up many times. But distance speed and time all depend on frames of reference. All you are doing is mixing frames of reference so you get faster than light. When if fact in no frame of reference you are going faster than light.

Yes I agree...my point is simply this: You can travel a light year in less then a year from your POV. Of course when you get to the place your flying to, a year would have passed as if time slowed down inside your ship.. that's always been my point when I first asked the questions, although now I understand why better thanks to the input from others.

an easy example is that many galaxies flying away are doing so faster then light. Their redshift proves this. Eventually the galaxy will out run the photons, and we will lose sight of it forever... a concept that freaks me out!

 

[WannabeNewton]

First of all, the ship is at rest in its own frame and time does NOT slow down inside the ship; an observer in his/her own reference frame measures time dilation for other moving frames. Secondly, the ship travels on a time - like geodesic and it is very easy to show that if a geodesic is time - like at some point on a manifold, it will be time - like at all points on the manifold for which it exists. A time - like geodesic cannot suddenly turn into a null geodesic.

 

[mark_gg]

First of all, the ship is at rest in its own frame and time does NOT slow down inside the ship; an observer in his/her own reference frame measures time dilation for other moving frames. Secondly, the ship travels on a time - like geodesic and it is very easy to show that if a geodesic is time - like at some point on a manifold, it will be time - like at all points on the manifold for which it exists. A time - like geodesic cannot suddenly turn into a null geodesic.

no idea what you mean.

A ship can travel 10 light years in less then 10 years from the POV of the ship... that is a fact.

 

[WannabeNewton]

The ship is at rest in its frame. The only non - vanishing component of its 4 - velocity in its frame is with respect to the time basis. It only travels through space from the reference frame of some other observer. Anyways, my point is that the ship cannot hit c because objects that travel at c travel on null geodesics (and massive particles travel on time - like geodesics) and as I said it is a trivial task to show that if a geodesic is time - like somewhere on the manifold it is time - like everywhere on the manifold so it cannot become null - like.

 

[Mordred]

Another way of thinking of what your describing is from the persons on the ship 'they are moving forward in time' not completely accurate but if you watch some of Stephen Hawking lectures he himself has used this as a viable means of of time travel. However its forward time travel. Yes we can use this to colonize another planet provided you can take everything you need to do so. As you would never be able to get any aid from the planet Earth. The amount of material needed to restart the species on another planet would require an extremely large ship there fore a ton of fuel,
One of the little thought of problems with that is the risk of diseases wiping out those ppl as our immunity systems have developed natural resistances to Earth diseases, Its highly probable that on another Earth like planet to come into contact tons of germs, viruses etc that we on Earth have never seen and therefore we would not have any defence against it.
The most likely scenario is that if you do send ppl that far away without support you would merely be sending them to their doom. NOt to mention all the risks of low gravity on a human body that is designed to deal with Earth like conditions. Scientists are still studying this problem for solutions, The amount of radiation that our solar system filters out also protects us but outside our solar system the passengers would get the full brunt of that that radiation, again scientists are designing better radiation protection but were years away from complete protection. In many ways its more practical to use the cryogenics method as you can use the cryogenics chanmbers as a means of protection and it would require a lot less feul.
YOu can use the pressure of the cryogenics chanber to offset the gravity loss problems that effect bone softening etc. Cryogenics I feel would be far more practical a method of colonization that utilizing GR.

 

[mark_gg]

All very interesting... Technically it would be difficult, but it is not impossible. Its hard for us to speculate on the technical problems from our primitive view in comparison to another 100, or 1000 years of scientific advancement.

I personally feel it is inevitable this event will happen, considering science is only 300 years old, and the human race is very likely going to be around for millions of years...many people disagree with this, but I don't see why. Disease, or nuclear war would obviously cripple civilization, but even if this happened it would be very unlikely every human on Earth would perish. The technologies we have invented, cannot be 'uninvented', along with the infrastructures we have built. We could never return to a cave man existence. Disease can be contained by science and common sense, and war can be avoided by good politics.

The Arab Spring, the creation of the EU, and the NATO alliance means as time goes on the world is becoming more democratic, and more liberal in its outlook. This means the likelihood of more power to large institutions such as the UN is likely, and ultimately I predict a 'World government'... once this is in place, the chance of war is remote as all countries will be bound legally, economically, and politically... attacking another country will just become attacking yourself. In Euruope for example the chance of a war between let's say Germany in France is practically zero. The EU legal framework and economic situation binds us together. War in Western Europe is almost a laughable concept now, but only 50 years ago it was very likely.

Soon Turkey will join. The first muslim country in the EU will absorb EU law on Human Rights etc... and I forsee this traveling East to the middle east and beyond. We can already see Iran, Syria, Libya, Egypt rising up against fascism. Libya, Egypt, Iraq and Afghanistan are now democracis (although still rife with problems), and the events in Syria & Iran will I think lead to increased decocratic reform. A dictator cannot dictate if his people ignore him.

I think the Chinese government is one of the biggest threats to world peace, but they are slowly opening up and liberalising as they have realized a free market, as well educated, technological advanced populations are better economically. Educated people want freedom, and the government will eventually have to cave into the cries of the people and increase Human RIght protections, and free media...etc...

Africa... who knows how that will go.

Basically I am very positive about how the world is going. A peaceful world means Science can advance at an exponential rate... and I predict within my lifetime we will see human beings exit the Solar System for the first time...

get back to me in 50 years. :-)

 

[Mordred]

I have little doubt that eventually when technologies improve enough and we do look into colonization its highly probable that the more practical method of Cryogenics will invariably be used however there is no reason why both methods cannot and in many ways should be used on the same trip. As this is now getting off topic I've probably said enough along those lines.

 

[bahamagreen]

Maybe what Mark_gg is imagining is this:

1] At rest within the solar system we note that a distant star is 10 light years away
2] Then we hop in a very fast ship and accelerate quickly up just short of c with respect to the solar system reference frame, which Earth folks see as a trip taking more than 10 years
3] Aboard ship the elapsed trip time with respect to ship reference frame is very short

So 'gg is taking the 10 ly distance from the solar system reference frame and comparing the elapsed time in the ship's reference frame to conclude that the ship went 10 ly in a short time.

The apparent contraction of distance between the ship and the star from the ship's reference frame is being "ignored" as is the time dilation... and so not used to calculate light speed locally within the ship's frame. As long as the passengers in the ship believe that the "correct" distance was 10 ly and the distance contraction is an illusory artifact of high speed; then their intuition will be that they did in fact make the trip "faster than light".

If all measurements were experimentally performed locally within the ship, the length contraction and time dilation would conspire to present c measuring 300K k/s just like within any other reference frame.

Maybe 'gg is discounting the ship's relativistic effects as illusory without realizing that all reference frames are subject to these effects?

Another thing that might be going on here... from the original question, I wondering if 'gg is trying to think of reference frames which "clearly" must be moving in relation to each other at >c speeds? This would lead to ideas like noting a solar system frame of reference and then positing another frame of reference (not a physical object but just the math/geometry of the other frame), and define that second frame as moving so as to cross the galaxy in 10 years... but of course the relativistic effects of how each frame sees the other would sort this out... and to make the original hypothesis would imply a third frame of reference from which to make the other two assignments.

 

[GammaR4yBurst]

I think that mark gg is confusing FTL travel with length contraction and time dilation?

And mark gg, I agree with you that sometimes a fresh perspective from an outsider helps push science in new directions, but you can't just invent an idea in your head if it violates all the rules that have been tested and proven.

Science grows and evolves when new material is added to older ideas and reinforces testable and observable data, or shown to be false or unprovable and cast away.

These people you are calling "rude" are just trying to help you understand things that you just arent making sense with. They arent trying to make you mad, or hurt your feelings, they are just trying to put forth the truth that has been uncovered in the last few hundred years of science.

I am a lot like you, I lay in bed at night and think about things like this too. But just because I come up with an idea that makes sense in my head, doesn't mean that it is true. Its just not the way things work.

-Remember that this forum isn't a place where snobby people look down on you for being dumb, they are just people who spend their lives and careers studying the things that people like you and me have a slight curiosity for...

GRB

 

[schonovic]

A really good book to read about what occurs close to the speed of light is Steven Hawking's "On the shoulders of giants". it goes into great detail showing that it is completely impossible for matter to reach the speed of light. it's not just about "from this or that persons point of view", it is about nothing reaching the speed of light in whatever area of space-time you are in. this does not however discuss warping or tunneling through space-time, wormholes, etc...

 

[JordanL]

It seems that what mark_gg is positing, is that SR is only useful for predicting how other reference frames will perceive you. If you do not care about any reference frame at any time except for the one you are currently in, then you can travel arbitrarily "fast" from your own perspective... that would of course mean ignoring how everything else ages around you.

SR is useful if you believe you are not the only person in existence that actually exists. That is, SR is useful unless you subscribe to the "brain in a jar" idea, where everything in existence is a figment of your imagination, and nothing but your consciousness actually exists, in which case physics itself would be pretty pointless.

 

[mark_gg]

From the beginning I simply meant that you could travel a light year in less than a year.. from your perspective only.

This is true because (as I said) acceleration has no limit FROM YOUR PERSPECTIVE ONLY.

I don't know why this was so controversial, and what I said was just confirmed later into the conversation anyway, but with more detail.

I would like people of Physics to educate the public more on this, as it is possible therefore to travel very long distances very quickly FROM YOUR PERSPECTIVE only, and it' is only a naive lack of imagination to say this technology would never be invented.

An 'easy' experiment to perform is to get a rocket to go close to FTL (from the perspective of Earth) and see if time dilation does occur in the way expected (could just put a watch in the thing).

 

[PAllen]

From the beginning I simply meant that you could travel a light year in less than a year.. from your perspective only.

This is true because (as I said) acceleration has no limit FROM YOUR PERSPECTIVE ONLY.

I don't know why this was so controversial, and what I said was just confirmed later into the conversation anyway, but with more detail.

I would like people of Physics to educate the public more on this, as it is possible therefore to travel very long distances very quickly FROM YOUR PERSPECTIVE only, and it' is only a naive lack of imagination to say this technology would never be invented.

An 'easy' experiment to perform is to get a rocket to go close to FTL (from the perspective of Earth) and see if time dilation does occur in the way expected (could just put a watch in the thing).

Well, from your (rocket) you have not traveled a light year in less than a year. You have traveled something much less than a light year per year. What you have done is travel Earth's light year in less than a year of your time. See the difference? It is simply a case of mixing quantities from different frames - a pure and simple mistake.

A true statement, totally non-controversial, is to state you can reach some destination in a relatively short time as experienced by you.

As to an experiment, the fastest any macroscopic body has been accelerated to by any known technologies relative Earth (by earthlings) is .00005 c. You have quite a few orders of magnitude to beat all the world's technology by for your 'easy' experiment.

 

[HallsofIvy]

From the beginning I simply meant that you could travel a light year in less than a year.. from your perspective only.

This is true because (as I said) acceleration has no limit FROM YOUR PERSPECTIVE ONLY.

And peopel keep telling you you are wrong (and telling you why) and you keep responding "Oh, so I'm right!" That's really amusing!

You seem to be focusing on one part- the fact that, if you are moving at relativistic speed "time slows down". So if you are going at, say 90% the speed of light (relative to us) so that it takes you 1/.9= 1.11... years to go one light year (again relative to us), the time passed for you will only be $(1.11)\sqrt{1- (.9)^2}= (1.11)(.436)= .484$ years. You have crossed a light year in only .484 years and so have been going at 1/.484= 2.06 times the speed of light!

But that is wrong because you have neglected the contraction of distance at your relativisitic speed. Relative to you you will only have gone 1(.436)= .435 light years, not one light year and so will have been going at .435/.484= .90 times the speed of light.

That is what every one has been trying to tell you and you have been ignoring.

I don't know why this was so controversial, and what I said was just confirmed later into the conversation anyway, but with more detail.

I would like people of Physics to educate the public more on this, as it is possible therefore to travel very long distances very quickly FROM YOUR PERSPECTIVE only, and it' is only a naive lack of imagination to say this technology would never be invented.

An 'easy' experiment to perform is to get a rocket to go close to FTL (from the perspective of Earth) and see if time dilation does occur in the way expected (could just put a watch in the thing).

(That's already been done and it did occur "in the way expected".)

One more time: you are WRONG, WRONG, WRONG!

(I'll be interested to see how you interpret that as saying you are right!)

 

[Dale]

This is true because (as I said) acceleration has no limit FROM YOUR PERSPECTIVE ONLY.

It is false because if you are using someone else's distance and your own time that is neither "YOUR PERSPECTIVE ONLY" nor anybody else's perspective only.

Anyway, necroposting is irritating.

 

[Nugatory]

An 'easy' experiment to perform is to get a rocket to go close to FTL (from the perspective of Earth) and see if time dilation does occur in the way expected (could just put a watch in the thing). ...
In my head this sounds perfectly possible, and quite easy... so why hasn't it been done?

Just for grins, you might try calculating the amount of energy required to accelerate a 1 kg spaceship to maybe 90% of the speed of light... That will tell you why we haven't performed this experiment. (Edit - I'm not being sarcastic with that "just for grins" bit - it really is fun. Google for "relativistic baseball" to see what I mean )

However, we routinely accelerate subatomic particles to relativistic velocities and observe them in our lab (I've done it myself, with high-speed electrons) and have observed the predicted length contraction, time dilation, and "mass increase". There's also a pretty good summary of the experimental proof at https://www.physicsforums.com/showthread.php?t=229034.

 

[russ_watters]

From the beginning I simply meant that you could travel a light year in less than a year.. from your perspective only.

This is true because (as I said) acceleration has no limit FROM YOUR PERSPECTIVE ONLY.

I don't know why this was so controversial, and what I said was just confirmed later into the conversation anyway, but with more detail.

I would like people of Physics to educate the public more on this, as it is possible therefore to travel very long distances very quickly FROM YOUR PERSPECTIVE only, and it' is only a naive lack of imagination to say this technology would never be invented.

That is wrong. It would APPEAR to be true if you closed the windows of your spaceship and ignored the time dilation and length contraction going on around you and based the travel calculations on Newton's laws. But ignoring those things doesn't make them go away.

An 'easy' experiment to perform is to get a rocket to go close to FTL (from the perspective of Earth) and see if time dilation does occur in the way expected (could just put a watch in the thing).

And indeed, its been done many, many times including continuously on dozens of GPS satellites.

 

[ZapperZ]

From the beginning I simply meant that you could travel a light year in less than a year.. from your perspective only.

This is true because (as I said) acceleration has no limit FROM YOUR PERSPECTIVE ONLY.

I don't know why this was so controversial, and what I said was just confirmed later into the conversation anyway, but with more detail.

I would like people of Physics to educate the public more on this, as it is possible therefore to travel very long distances very quickly FROM YOUR PERSPECTIVE only, and it' is only a naive lack of imagination to say this technology would never be invented.

An 'easy' experiment to perform is to get a rocket to go close to FTL (from the perspective of Earth) and see if time dilation does occur in the way expected (could just put a watch in the thing).

May I suggest a change in attitude in the future? Rather than assume that you've found some new tests or think that you are exploring something that no physicists have ever even thought of (which makes a nasty assumption that we are THAT dumb), try just ASKING if such-and-such has been tested.

Time dilation experiment? There has been NUMEROUS examples of this. As has been pointed out, your GPS strongly depends on such time correction. And there are other direct, more stringent experiments on this:

http://www.nature.com/nphys/journal/v3/n12/abs/nphys778.html

There are many places on the web (and even a few threads in this forum) that have presented clear, easy lessons in relativity. However, on the part of the general public, you can't simply be lazy and expect to be spoon-fed and understand these things right away! Physics, as with mathematics, can't be understood simply from just reading things. It is an active lessons that requires calculations and repeated work for it to sink in! You can only understand things superficially without doing the necessary work. There is no short cut!

Zz.

 

[Darko M]

Well, I believe some day to come, the constancy of c would be demystified with reasonable evidence.

 

[HallsofIvy]

I just noticed, after reading Dale Spam's remark, that mark_gg had reposted to a thread two years old!

In any case, Darko M, what do you mean by "demystified"? I was not aware that "the constancy of c" was at all "mystified" and there is plenty of evidence.