lightspeed

[goku]

i just can't get over it, someone said it again on the history chanel i think.

"you can't go the speed of light because E=MC2 blah blah you get fatter the faster you go"

i don't understand, it's not like they're useing "you can't go the speed of light" to cover up something

maybe they just missed it, standing too close to focus on the truth, an honest mistake.

to acheave acceleration you must overcome resistance.
the question is, how much resistance is in space?

[Moontanman]

Originally Posted by goku

i just can't get over it, someone said it again on the history chanel i think.

"you can't go the speed of light because E=MC2 blah blah you get fatter the faster you go"

i don't understand, it's not like they're useing "you can't go the speed of light" to cover up something

maybe they just missed it, standing too close to focus on the truth, an honest mistake.

to acheave acceleration you must overcome resistance.
the question is, how much resistance is in space?

Goku, the resistance you have to over come has nothing to do with friction of the medium, when you accelerate an object you have to use energy in some form to do it. At speeds less than 80 or 90 % of the speed of light it's pretty straight forward, energy input makes the object go faster. But when you start getting close to the speed of light a strange thing happens. Some of the energy used to accelerate the object begins to actually make the object more massive than it was. (time also slows down and the object becomes shorter) This of course means it takes even more energy to accelerate the object. But instead of all the energy making the object go faster even more of the energy goes into making the object more massive. The closer you get to the speed of light more of the energy used goes into making the object more massive instead of making it go faster. As you approach the speed of light all the energy goes into making the object more massive instead of making it go faster. The object actually resists movement by becoming more and more massive. As the object comes to the speed of light the amount of energy required to accelerate the object becomes infinite and the object becomes infinitely massive. (To me this looks like the object would disappear into a black hole and a singularity but I'm not schooled enough to know if this is true.) If you want to know why this happens someone with better math skills than me will have to tell you.

[goku]

Originally Posted by Moontanman

Goku, the resistance you have to over come has nothing to do with friction of the medium, when you accelerate an object you have to use energy in some form to do it. At speeds less than 80 or 90 % of the speed of light it's pretty straight forward, energy input makes the object go faster. But when you start getting close to the speed of light a strange thing happens. Some of the energy used to accelerate the object begins to actually make the object more massive than it was. (time also slows down and the object becomes shorter) This of course means it takes even more energy to accelerate the object. But instead of all the energy making the object go faster even more of the energy goes into making the object more massive. The closer you get to the speed of light more of the energy used goes into making the object more massive instead of making it go faster. As you approach the speed of light all the energy goes into making the object more massive instead of making it go faster. The object actually resists movement by becoming more and more massive. As the object comes to the speed of light the amount of energy required to accelerate the object becomes infinite and the object becomes infinitely massive. (To me this looks like the object would disappear into a black hole and a singularity but I'm not schooled enough to know if this is true.) If you want to know why this happens someone with better math skills than me will have to tell you.

if that where true then the movie "honey i shrunk the kids" would also be true.
oh and what you're saying has been proven because man has came so close to the speed of light so many times.

and i reckon those protons in the proton accellerater also get bigger?

[Moontanman]

Originally Posted by goku

if that where true then the movie "honey i shrunk the kids" would also be true.
oh and what you're saying has been proven because man has came so close to the speed of light so many times.

and i reckon those protons in the proton accellerater also get bigger?

As I said before I really don't have the math skills to explain why these things happen btu i do understand that they do.

No shrinking kids, we are talking about high speeds not shrinking anything. The object becomes shorter along the axis of acceleration not smaller. Yes protons in an accelerator do indeed become shorter along the axis of acceleration and they become more massive (not bigger) as they get closer to the speed of light. Think of a proton as a sphere at rest, as it accelerates it becomes squashed into an oblate spheroid as it goes faster it becomes a disk thinner and thinner as it goes faster but it's diameter stays the same. No humans cannot accelerate space ships that fast but we can accelerate atoms and particles close to the speed of light and the things I describe hold true for them, these things would also hold true for a space ship. Objects get shorter along the axis of acceleration, time slows down for them, and they get more massive. The really cool thing is that if you were on the space ship it would appear to be the same but the rest of the universe would appear to be compressed.

[Jay-qu]

Actually they get smaller - from our frame of reference. They gain more inertial mass, not rest mass.

We come close to the speed of light but we also know we cant exceed it, if you will allow a slight bit of math jargon its called an asymptote.

[Moontanman]

Originally Posted by Jay-qu

Actually they get smaller - from our frame of reference. They gain more inertial mass, not rest mass.

We come close to the speed of light but we also know we cant exceed it, if you will allow a slight bit of math jargon its called an asymptote.

I saw a show the other day that described particles close to C as being shorter along the axis of acceleration not smaller, they were quite adamant about it. They were displayed as thin disks going around the accelerator. Yes I should have specified it was inertial mass and not rest mass, sorry. Actually I might have read it, when I read I often see things visually instead of words on the page.

[Janus]

Originally Posted by goku

i just can't get over it, someone said it again on the history chanel i think.

"you can't go the speed of light because E=MC2 blah blah you get fatter the faster you go"

i don't understand, it's not like they're useing "you can't go the speed of light" to cover up something

maybe they just missed it, standing too close to focus on the truth, an honest mistake.

to acheave acceleration you must overcome resistance.
the question is, how much resistance is in space?

To achieve acceleration you must overcome inertia. IOW, any object will resist having its velocity being changed, regardless of whether it is in space or not.

It takes energy to change the velocity of an object.

Now, up to a little over a hundred years ago, we used the formula



To determine how much energy it would take to accelerate a body of mass M to a velocity of V.

Then Einstein developed the Theory of Relativity.
In it, he determined that the above equation was not correct, and that proper equation would be:



Where c is the speed of light in a vacuum.

Now this equation, for low values of v, gives almost exactly the same answer as the first equation, which is why nobody ever noticed anything was wrong. Even today when dealing with speeds small when compared to the speed of light we use the first equation because it is easier, and the difference in the answers is too small to cause any problems.

But, as v gets closer to c, the two equations begin to differ quite a bit. in fact, as the velocity approaches c, the energy needed to reach that speed approaches infinity.

The very particle accelerators you mention demonstrate this fact. We have pumped many times the energy into a proton than needed to accelerate that proton faster than c according to the old equation, and have never been able to get a proton to travel at or faster than c. We have gotten very close, but that is all. In addition, if you take the speed which you did get the proton up to, and the energy it took to do it, it matches what Einstein's equation said it should be.

[Jay-qu]

Originally Posted by Moontanman

I saw a show the other day that described particles close to C as being shorter along the axis of acceleration not smaller, they were quite adamant about it. They were displayed as thin disks going around the accelerator. Yes I should have specified it was inertial mass and not rest mass, sorry. Actually I might have read it, when I read I often see things visually instead of words on the page.

smaller = shorter, but no I didnt specify that this contraction only occurs along the direction of motion (naughty me).

[dkv]

There is a huge misunderstanding. What theory suggests is that the speed of light is measured constant when the frame of references are inertial.
At the quantum mechanical level speed of light is no longer considered constant.
Moreover c is not constant when we measure speed of light in plasma or glass...
Even the Vaccum is filled with virtual photons and electrons.. Speed of light is never constant.

Moderation note: This post and replies to it were moved to the Math and Physics forum thread Is the speed of light not constant at the quantum mechanical level?, because they had drifted far from the original subject of the speed of light in vacuum as a “universal speed limit”.

[goku]

Originally Posted by Moontanman

No shrinking kids, we are talking about high speeds not shrinking anything.

no really, if going fast makes you bigger then going slow would make you smaller.
every action has an equal opposite reaction.

the math part just doesn't work, you can't give a mathmatical value to something by picking a number between 1 and 100.

if resistance is 5 and thrust is 6, 6 being greater than 5, then you acheave acceleration. the longer you can accelerate the greater your speed will become.

after you break the photonic barrier things should smothe up nicely

of course the real problem will be running into stuff, the faster you go the worse the wrech will be