fastest speed reached by man?

Tefal said:
I'm pretty sure in the partical accelerators they recorded particals increasing n mass + requiring more energy to accelerate.
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Mass appears to increase from the viewpoint of the outside observer. It's all relative, hence the name of the equation.
 
Tefal said:
I'm pretty sure in the partical accelerators they recorded particals increasing n mass + requiring more energy to accelerate.
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They require more energy to accelerate, yes, but their mass doesn't change, by definition of the term. The term mass in relativity usually refers to the rest mass of an object: the ratio between the square of c, the speed of light, and the energy of an object measured from its rest frame (i.e. while stationary with respect to the object). Since this definition comes directly from the object's rest frame, it's an intrinsic property of that object and doesn't change if the object is moving with respect to the observer.
 
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didnt they manage a small time travel thing with the sr71 using 2 atomic clocks both set to the same time on earth 1 on the blackbird the other back at base the pilot i believe went to top speed and got the clock 3 seconds ahead of the one below on the ground when the put them next to each other, i saw the documentary on discovery channel
 
Inquisitor said:
They require more energy to accelerate, yes, but their mass doesn't change, by definition of the term. The term mass in relativity usually refers to the rest mass of an object: the ratio between the square of c, the speed of light, and the energy of an object measured from its rest frame (i.e. while stationary with respect to the object). Since this definition comes directly from the object's rest frame, it's an intrinsic property of that object and doesn't change if the object is moving with respect to the observer.
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Just to expand on this, the famous equation E = mc² relates the rest mass of an object to its rest energy, not its total energy.

If you want the total energy, you need to bring in the Lorentz factor, which gives you E = γmc².

daz said:
Finally someone with a non-layman understanding of SR. :cool:
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Just realised the beginning of my second sentence is almost identical to the start of the wikipedia article on rest mass – I didn't steal it, honest :p

I'm still pretty shaky on SR though!
 
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Tefal said:
star trek uses a warp bubble to avoid this problem, wars goes through a different kind of space (hyperspace) to avoid it :p
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That's not correct, it uses a theoretical device that expands the space behind it and contracts the space in front, indeed warping space. Its the same as large mass warps space.
 
How about this:

If your spacecraft is going at the speed of light (and is using infinite energy to power it) what happens if you get out and push?

Also, if to go at the speed of light requires infinite energy, why does light not have infinite energy?

God, I'm rubbish at this.
 
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