Why matter can't reach the speed of light ?

[Naty1]

Time dilation and length contraction are two sides of the same coin - you can't have one without the other.

This is perhaps the most fundamental aspect of special relativity to me...
other than the fixed speed of light of course...

Space and time morph into each other...change places...if one changes so does the other.

All we need is some 'rational' explanation!

 

[russ_watters]

I think the biggest problem people have with that is that because we are humans, it is difficult for us to travel fast enough for relativity to matter. We can do it in an airplane and verify with an accurate clock that it works, but we can't measure the distance the airplane traveled accurately enough to see the length contraction.

As a result, we have to use examples where we have to put ourselves in the reference frame of other objects (like muons) that experience the contraction.

 

[Dale]

Why we can not reach electron to c ?

I would say "because an electron has mass". By virtue of having mass an electron must also have more energy than momentum (in units where c=1). Things which travel faster than c have more momentum than energy and things which travel at c have the same amount of momentum and energy.

But all of the reasons you gave are also valid.

 

[Mentz114]

This is perhaps the most fundamental aspect of special relativity to me...
other than the fixed speed of light of course...

Space and time morph into each other...change places...if one changes so does the other.

All we need is some 'rational' explanation!

There is no 'rational' explanation of the type you want. The impossibility of accelerating a mass to sol is not a property of the mass itself but of spacetime. The morphing you speak of is a good hint that it is spacetime that changes, not the bodies in question.

Most of the posts in this thread are in denial and are stalled for pre-relativistic intuitive reasons.

 

[RealityQuest]

There is no 'rational' explanation of the type you want. The impossibility of accelerating a mass to sol is not a property of the mass itself but of spacetime. The morphing you speak of is a good hint that it is spacetime that changes, not the bodies in question.

Most of the posts in this thread are in denial and are stalled for pre-relativistic intuitive reasons.

I would be the first to admit I am stalled for pre-relativistic intuitive reasons. My 'denial' is I don't know how to take a meaning leap, honestly stating that I see how the faster I run, the more the universe contracts in that direction (however slightly).

 

[1977ub]

I would be the first to admit I am stalled for pre-relativistic intuitive reasons. My 'denial' is I don't know how to take a meaning leap, honestly stating that I see how the faster I run, the more the universe contracts in that direction (however slightly).

Only for you. Think about how you would measure the length of a bench you are running past, and then think about how you would do it if you were running.

 

[jtbell]

Time dilation and length contraction are two sides of the same coin - you can't have one without the other.

Better: they're two (out of three) sides of the same triangle, the third side being relativity of simultaneity.

 

[Mentz114]

I would be the first to admit I am stalled for pre-relativistic intuitive reasons. My 'denial' is I don't know how to take a meaning leap, honestly stating that I see how the faster I run, the more the universe contracts in that direction (however slightly).

If you do make the leap, it will free you from the search for 'mechanical' explanations. Most people are saying, put it down to relativity of simultaneity and be done.

 

[RealityQuest]

Better: they're two (out of three) sides of the same triangle, the third side being relativity of simultaneity.

And relativity of mass, right? There appear to be four. Relativity of length, duration, simultaneity, and mass.

I think I see where I was getting stuck. Relativity only describes two objects or rest-frames at a time. I was trying to show how a third rest-frame would contradict the conclusions reached among the other two, but (eureka!) that's why the theory is called "relativity." In my defense, I didn't realize I was doing that until I tried to come up with an experiment to affirm or contradict my sense. My feeling was that the ground frame should somehow tie the other two together.

While I think I'm getting closer to grasping the logic and math of relativity, I still find something unsatisfying about it. To attribute relativistic behavior to "rules" governing how the universe works suggest a very Matrix-like universe to me. Even worse, every person (every subatomic particle) seems to carry it's own Matrix. I want someone to explain WHY c is the maximum velocity, not just assert that it just appears to be the rule.

The limit of relativity to only describe two bodies at a time in isolation also seems like a weakness. To me, at the moment, it seems to lack a certain holism...

But I am still chewing on it.

 

[Naty1]

I want someone to explain WHY c is the maximum velocity, not just assert that it just appears to be the rule.

To derive that from first principles would be great. But when you request that answer, be sure to also ask why we have four different forces, why the mass and charge of the electron is what we observe [ditto for the other fundamental particles] and why our man made math sometimes even fits the universe.

Regarding getting stalled, nothing is more misleading that V[total] = V1 + V2. And that
V = at...assuming uniform acceleration...we all 'learn' those and follow the 'logic' until relativity...then comes quantum mechanics, which is crazier still!

 

[Mentz114]

And relativity of mass, right? There appear to be four. Relativity of length, duration, simultaneity, and mass.

I can't agree with that. Energy is relative but rest mass ( as in inertial) is an invariant.

I think I see where I was getting stuck. Relativity only describes two objects or rest-frames at a time. I was trying to show how a third rest-frame would contradict the conclusions reached among the other two, but (eureka!) that's why the theory is called "relativity." In my defense, I didn't realize I was doing that until I tried to come up with an experiment to affirm or contradict my sense. My feeling was that the ground frame should somehow tie the other two together.

...

The limit of relativity to only describe two bodies at a time in isolation also seems like a weakness. To me, at the moment, it seems to lack a certain holism...

I don't know why you think relativity only describes two objects at a time. It is true that relative velocity is a binary relation - but all pairs of objects have a relative velocity, and all inertial frames are equivalent.