Why nothing can go faster than speed of light.

[DimaMazin]

And how does he do that?

 

We seem to have confused the quoting system.

@ Janus - Even in your answer your pairs of clocks they are even with even, odd with odd.

For example light shows clock indication as t then t'=t+distance/c

[Robittybob1]

For example light shows clock indication as t then t'=t+distance/c

On the surface that seems logical. Then we could also check the non equidistant clocks. I wonder if Janus can see a fault in that?

[DimaMazin]

On the surface that seems logical. Then we could also check the non equidistant clocks. I wonder if Janus can see a fault in that?

I have mistaken

 

For example light shows clock indication as t then t'=t+distance/(c*gamma)

That was only for motionless clock. It is for any clock.

Edited March 12, 2016 by DimaMazin

[bluescience]

Well you would have to take this a bit behind. First you must now Einstein's famous equation of E=mc² and the fact that the more mass an object has the more energy is required to accelerate it. You must also know that kinetic energy is the energy an object has due to its motion. So as something starts moving at a fixed speed, its kinetic energy is constant. However the moment the object accelerates, its kinetic energy increase. And kinetic energy is simply energy, the word "kinetic" behind it simply specifies the type of energy. Taking the previous statement into consideration and applying it to the Einstein's formula: E=mc², we deduce that mass increases as an object accelerates(not as it moves at a constant speed). So when an object tries to reach the speed of light it simply keeps on increasing in mass. Now according to Newtonian physics, the more the mass of an object, the more energy is required for it to accelerate. So while the object is reaching the speed of light, in that case it mass becomes infinite. It is almost like a function in mathematics reaching a limit or an asymptote, in which it becomes infinitely closer to the number or asymptote it is approaching. In the same manner anything with mass will become infinitely closer to the speed of light as it increases but will never reach the speed of 186000 mi/s(speed of light). And in the process of reaching the speed of light, its mass grows infinitely, and thus it would recquire and infinite amount of energy to sustain the speed of light for anything with mass. This last statement is the result of the formula: E=mc² . If you have infinite mass in the formula, then you must have and infinite amount of energy to sustain the infinite mass which is the effect of an object moving at the speed of light.

 

 

Thus, only light and other waves that have no intrinsic mass, can reach the speed of light.

[swansont]

Well you would have to take this a bit behind. First you must now Einstein's famous equation of E=mc² and the fact that the more mass an object has the more energy is required to accelerate it. You must also know that kinetic energy is the energy an object has due to its motion. So as something starts moving at a fixed speed, its kinetic energy is constant. However the moment the object accelerates, its kinetic energy increase. And kinetic energy is simply energy, the word "kinetic" behind it simply specifies the type of energy. Taking the previous statement into consideration and applying it to the Einstein's formula: E=mc², we deduce that mass increases as an object accelerates(not as it moves at a constant speed). So when an object tries to reach the speed of light it simply keeps on increasing in mass. Now according to Newtonian physics, the more the mass of an object, the more energy is required for it to accelerate. So while the object is reaching the speed of light, in that case it mass becomes infinite. It is almost like a function in mathematics reaching a limit or an asymptote, in which it becomes infinitely closer to the number or asymptote it is approaching. In the same manner anything with mass will become infinitely closer to the speed of light as it increases but will never reach the speed of 186000 mi/s(speed of light). And in the process of reaching the speed of light, its mass grows infinitely, and thus it would recquire and infinite amount of energy to sustain the speed of light for anything with mass. This last statement is the result of the formula: E=mc² . If you have infinite mass in the formula, then you must have and infinite amount of energy to sustain the infinite mass which is the effect of an object moving at the speed of light.

 

 

 

Kinetic energy is kinetic energy, not mass energy. E=mc² was derived/defined for an object at rest.^. The equation for a moving object is E² = p²c² + m²c⁴

 

The momentum of an object tends to infinity as the speed approaches c, so the kinetic energy must as well.

[bluescience]

 

 

Kinetic energy is kinetic energy, not mass energy. E=mc² was derived/defined for an object at rest.^. The equation for a moving object is E² = p²c² + m²c⁴

 

The momentum of an object tends to infinity as the speed approaches c, so the kinetic energy must as well.

oh. im not sure tho, since my knowledge of this topic comes from the second party books, not from the writings of Einstein himself. therefore you propbably are right if you are sure about your knowledge. also just as a question, what is momentum? like what is it in physics. Isn't it just kinetic energy or just the your motion itself?

Edited March 31, 2016 by bluescience

[The Think3r]

Theoretically how much energy would it take for you(ignoring the damaging pressure) to move at the speed of light?

[Strange]

Theoretically how much energy would it take for you(ignoring the damaging pressure) to move at the speed of light?

 

An infinite amount. It is not possible to travel at the speed of light.

 

And why would there be any damaging pressure? It is not really any different from travelling at a few hundred miles per hour, which people do routinely. And, as all speed is relative, you are already travelling at over 90% of the speed of light with respect to something, somewhere!

[The Think3r]

 

An infinite amount. It is not possible to travel at the speed of light.

 

And why would there be any damaging pressure? It is not really any different from travelling at a few hundred miles per hour, which people do routinely. And, as all speed is relative, you are already travelling at over 90% of the speed of light with respect to something, somewhere!

 

I mean out side of Earth's electromagnetic field. Even at a few hundred miles an hour you still have a significant amount of pressure on your(or another's) person. 1G is the regular amount of pressure on a person on planet Earth but say 100 MPH in space would produce a lot less pressure on a body than on Earth. But the faster you go the more pressure you carry. Space travel generates remarkably little G-force, but at or near light speed it can be similar to being dragged through a hole the size of an apple and that's without the affects of other celestial bodies. It wouldn't cause pain, but neither would going through a black hole. A black hole wouldn't cause pain because depending on how you enter its field it would not allow your nerves to send the feeling of pain to your brain.

[Strange]

I think you are confusing acceleration and velocity.

 

Rapid acceleration produces pressure (as when you put your foot down in the car or take off in a rocket). This is equivalent to the "g force" of gravity.

 

However, if you accelerate at 1g, say, then you can get up to very high speed. If you accelerated at this (comfortable) rate for 2 years you would be going at 97% of the speed of light.

[The Think3r]

I think you are confusing acceleration and velocity.

 

Rapid acceleration produces pressure (as when you put your foot down in the car or take off in a rocket). This is equivalent to the "g force" of gravity.

 

However, if you accelerate at 1g, say, then you can get up to very high speed. If you accelerated at this (comfortable) rate for 2 years you would be going at 97% of the speed of light.

 

Maybe I am but I am still curious as to how much energy/force/gravity it would take to travel at the exact(or as close as possible to) as the speed of light in the shortest amount of time possible.

[Strange]

 

Maybe I am but I am still curious as to how much energy/force/gravity it would take to travel at the exact(or as close as possible to) as the speed of light in the shortest amount of time possible.

 

You would need to know the mass, the speed and the time to get to that speed. From those it would be possible to calculate it.

[The Think3r]

Mass=72.2663364 kilograms

Speed=Light speed

Time=Up to a year

[Delta1212]

 

Maybe I am but I am still curious as to how much energy/force/gravity it would take to travel at the exact(or as close as possible to) as the speed of light in the shortest amount of time possible.

There is no closest speed. If you are traveling at 99.99999999999% of the speed of light, you can always get to 99.999999999999999% of the speed of light. And each additional 0.0...9 take an increasing amount of energy, which means that the energy requirement extends to infinity the closer you get, so there's no specific value that can be given unless you define exactly how close you want to get, which "as close as possible" doesn't do for the above stated reason. You can always get closer.

[Strange]

Why is mass given to 7 decimal places, but the others aren't?

 

You need to be specific about the speed. There is huge difference between 99.99% and 99.999% of the speed of light. For example, at 1g it would take 5 years to reach 99.993% c. But another three years to reach 99.99998% c.

 

And "up to a year" doesn't really mean anything. 1 nanosecnd or 11 months and 30 days both fit that definition.

[Delta1212]

Mass=72.2663364 kilograms

Speed=Light speed

Time=Up to a year

The speed can't be the speed of light. It can be any specific value under the speed of light, which is usually most easily expressed as a percentage of the speed of light if you want to talk about approaching it.

 

But 99% of the speed of light has a very different answer than 99.9% of the speed of light which has a much different answer than 99.99% of the speed of light.

Edited April 8, 2016 by Delta1212

[Strange]

This page has a very detailed analysis of relativistic acceleration and the fuel needed: http://math.ucr.edu/home/baez/physics/Relativity/SR/Rocket/rocket.html

[Thorham]

According to current theory and experiments you certainly can't even get to the speed of light unless you have no rest mass. However, that doesn't mean that it's impossible in all of reality

[kjelleman]

The reason is that the force between objects is mediated at speed of light so if the object travels at the speed of light there won't be any active force on it and it can therefore not be accelerated further. So the basic question is: why is force mediated at speed of light?

[Janus]

The reason is that the force between objects is mediated at speed of light so if the object travels at the speed of light there won't be any active force on it and it can therefore not be accelerated further. So the basic question is: why is force mediated at speed of light?

This is incorrect. Even if we were to stipulate that you couldn't push something to greater than c speed relative to you for this reason, this would not explain why a rocket could not exceed light speed, as the velocity of a rocket is not limited to its exhaust velocity. (Modern chemical rockets can only generate exhaust velocities of ~4.5 km/sec, yet routinely attain velocities of better than 7 km/sec in order to achieve low Earth orbit.)

 

The c speed limit is "built in" to the very nature of space and time.

[kjelleman]

This is incorrect. Even if we were to stipulate that you couldn't push something to greater than c speed relative to you for this reason, this would not explain why a rocket could not exceed light speed, as the velocity of a rocket is not limited to its exhaust velocity. (Modern chemical rockets can only generate exhaust velocities of ~4.5 km/sec, yet routinely attain velocities of better than 7 km/sec in order to achieve low Earth orbit.)

 

The c speed limit is "built in" to the very nature of space and time.

It is not a stipulation. Even your rocket need to obey the fact that every interaction basically is an interaction at a distance and this interaction is mediated at the speed of light. So if your rocket travel at speed of light and tries to accelerate through the repulsion effect there won't be any repulsion since the mediator of the force will not be received by the rocket/exhaust. (This mediator has the name photon)

[Tim88]

It is not a stipulation. Even your rocket need to obey the fact that every interaction basically is an interaction at a distance and this interaction is mediated at the speed of light. So if your rocket travel at speed of light and tries to accelerate through the repulsion effect there won't be any repulsion since the mediator of the force will not be received by the rocket/exhaust. (This mediator has the name photon)

 

That sounds good, but I think that I can show that it is incorrect, as Janus remarked.

 

Let's try this: if your reasoning were to -the-point, then this means, if I correctly understand your "there won't be any repulsion", that at say 0.99999c the rocket's push will be very small according to you, and so the push will be ever smaller and smaller when going faster, and that is why the rocket cannot reach c?

 

If yes, then I will continue (or maybe someone else who knows what I'm getting at will do so, that's OK).

[swansont]

It is not a stipulation. Even your rocket need to obey the fact that every interaction basically is an interaction at a distance and this interaction is mediated at the speed of light. So if your rocket travel at speed of light and tries to accelerate through the repulsion effect there won't be any repulsion since the mediator of the force will not be received by the rocket/exhaust. (This mediator has the name photon)

 

 

If we're still keeping the notion of inertial frames all being equivalent, I think the concept of the reactions being mediated at c is irrelevant in this objection. Locally, there is no motion for which one must account. The e.g. rocket combustion is at rest, as far as it's concerned.

[Bird11dog]

THE PROBLEM i SEE WITH THE ARGUMENT IS THAT WE ARE USING OUR FRAME OF REFERENCE TO MEASURE c. If we are on the ship traveling at .9999c and we measure how fast we are moving we find Our velocity to be much faster than c.

[swansont]

THE PROBLEM i SEE WITH THE ARGUMENT IS THAT WE ARE USING OUR FRAME OF REFERENCE TO MEASURE c. If we are on the ship traveling at .9999c and we measure how fast we are moving we find Our velocity to be much faster than c.

 

 

No, it doesn't work this way. c is the same no matter what inertial frame you're in.