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1

It's a perfectly valid interpretation. If you have a look at the question How long would it take me to travel to a distant star? you'll find it's quite possible to cover a distance greater than $ct$ in an elapsed time $t$. But this doesn't mean special relativity is wrong - indeed the calculations done in that Q/A were done using special relativity. The ...


0

One can in principle travel a given distance along a ruler in arbitrary short time. The relevant velocity definition is proper velocity: the distance measured by an observer at rest with respect to the ruler, divided by the time passing on the wristwatch of the traveller. Note that proper velocity deploys a mixture of reference frames, whereas ordinary ...


0

Note that what you describe is: applying enough pressure, to make an object go very fast. It makes absolutely no difference if your technique for doing that is "A BMW engine" "A Ferrari engine" or "swinging on string" -- or, any other technique! Your question is, essentially, the same as if you asked: "I know you can't make something go faster than the ...


1

I think the basic misunderstanding is that you are using classical mechanics in a situation that needs relativistic mechanics. Even if you have a strong chord relativistic mechanics tells us that as the linear velocity approaches c the inertial mass becomes infinite. That the linear velocity is increased tangentially is an irrelevant detail .


1

Let's have a look at your setup for spinning the mass at the end of the cord: To accelerate the mass you need to be able to apply a tangential force, and this requires the angle between the cord and the line to the pivot point be greater than zero. Specifically, if the tension in the cord is $T$ then the tangential acceleration is: $$ a_t = T\sin\theta ...


0

Time is that which is measured by clocks. How clocks behave when they are being moved relative to each other is simply a collection of experimental facts. At no time do we need any light to do those experiments, and it totally doesn't matter to moved clocks if we are moving them during the day or the night. So what, exactly is your question? Is it why ...


1

"Most probably in reality there are some extremely complex laws and equations which makes this question more complicated." Not really. The equations are rather straightforward. Let's measure velocities in units of the speed of light and let's denote the velocity of $B$ as observed by $A$ as $v_{BA}$, the velocity of $A$ as observed by $C$ (the ...


0

Special relativity is often introduced to students using light clocks because this is a reasonably accessible way to understand that phenomena like time dilation and length contraction must occur. However you should not be mislead into thinking that we use light clocks to define special relativity. The fundamental principle of special relativity (and in fact ...


1

That light has a fixed velocity in vacuum comes from observations . In order to fit the data Lorenz transformation were imposed on the rigorous mathematical model for electromagnetism, Maxwell's equations. It was the result of attempts by Lorentz and others to explain how the speed of light was observed to be independent of the reference frame, and to ...


4

In your frame of reference, it does indeed look as though the difference in speed between A and B is greater than $c$. But the question is - does A think that B is moving away at that speed? And the answer is "no". There is a thing called the Lorentz transformation which describes how the observed speed of an object is a function of the speed of the ...


-4

Actually, this might be possible. Mass is proportional to speed and light speed gives the limit at infinity, but this only accounts for particles with mass, for particles without mass this won't affect, I think. The eq. for relative mass becomes infinite for particle with least mass, but not zero mass. For objects with zero mass going at light speed , the ...


1

No. Not at the LHC and not at an even more powerful accelerator in the future. Now matter how much energy the accelerated particles acquire, they will never be able to surpass the speed of light. A massive particle like the ones at the LHC, i.e. one with non-vanishing rest mass, will not even reach the speed of light, it will only come arbitrarily close to ...


-1

This is a question that is asked the world over and the answer seems obvious to me, yet everyone deems it to be from perception which for me seems to be the issue apply some 1st grade logic to the situation and the answers reveal themselves quite simply. For instance, travelling faster than light from a single point of perception this is absolutely possible ...


1

If there were a particle that traveled faster than $c$, we would call it a tachyon. Such a particle would indicate that we fundamentally misunderstand the structure of spacetime, since travel faster than $c$ is forbidden in special and general relativity. There is no experimental evidence for any such particle. More realistically, tachyons indicate problems ...


1

A material object may hit the (spacelike) singularity (like one inside the Schwarzschild black hole) at any speed smaller than $c$, if measured from the frame in which the singularity itself is described by $t={\rm const}$. In other words, the angle in the Penrose causal diagram between the incoming trajectory of the doomed massive object and the horizontal ...


2

if higher speed than the speed of light will be discovered, will scientists be able to adjust the special relativity to the new situation? I suppose so. Science has encountered paradigm-shifting discoveries many times, and has always come up with new ways to describe reality. If this does happen, it could be an adjustment to special relativity, or ...


1

I am sorry to say that I can not agree with previous answers. We believe, but do not know for sure, that light from some galaxies will never reach us. This has nothing to do with the fact that they are moving away from us at more than the speed of light. Rather, it is assumed that these galaxies, like us, are not moving relative to the special frame in ...


4

I am aware that my answer can sound surprising, too simple to be true, but please take a deep breath before downvoting.The answer has little to do with relativity. In SR it is the moving object that gets shorter , but space is stable. In such a universe, even if a body is receding at 2,3,30 c, its light will reach us sometime, and the time is short as it ...


6

Let me present a slightly different perspective to Luboš, though I'm saying basically the same thing. From our current location we can define an area of space called the future light cone. This is the region of spacetime that is connected to us by motion at less than or equal to the speed of light. If we draw a spacetime diagram then the lightcone looks ...


3

The relative speed between two objects is only restricted within the special theory of relativity. These restrictions are only guaranteed to apply in general relativity – the theory of curved space that you need for the Big Bang theory – if the space surrounding the objects is the flat Minkowski spacetime, or at least can be approximated by the flat ...


1

For the observer traveling faster than the speed of light the light of the laser must appear to move away from him at the speed of light. For the observer in the rest frame, the laser light travels slower than the person firing it. I conclude that time is moving backwards for the guy with the laser... But seriously - we are breaking laws of physics here. ...



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