# The Naked Scientists Forum

### Author Topic: Can we rotate something faster than the speed of light?  (Read 3460 times)

#### Brandon Rock

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##### Can we rotate something faster than the speed of light?
« on: 01/03/2011 10:30:03 »
Brandon Rock  asked the Naked Scientists:

Hi

Hypothetical question about breaking light speed:

I know this is no way possible (centrifugal forces etc) but in theory is it possible?
I base my theory on have an ultra long "carbon nano" tube and spinning it on its axis.

Herewith my calculations:

Speed of light v=3x10e8

10km nano tube
piD = pi x 10km = 31.415km
31.415 x 1000m = 3141.5m
v/3141.5
=9549.57 RPS
=572974 RPM
So if we spin the nano tube at 572974 RPM the end part should be travelling the speed of light.

10 000km nano tube
piD = pi x 10 000km = 31 415.92km
31 415.92 x 1000m = 31 415 926m
v/circumference
=9.54 RPS
=572.95 RPM
Here 572.95 RPM = v. If we spin it a little faster eg: 600 RPM would the ends of the nano tube be travelling faster than light?

Kind Regards

Brandon Rock

What do you think?
« Last Edit: 01/03/2011 10:30:03 by _system »

#### graham.d

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##### Can we rotate something faster than the speed of light?
« Reply #1 on: 01/03/2011 12:48:29 »
It would take infinite energy to get the ends of the tube to light speed, so it is not possible, even theoretically.

#### JP

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##### Can we rotate something faster than the speed of light?
« Reply #2 on: 01/03/2011 15:13:27 »
Graham's right.  Also, as you go faster and faster, I suspect that eventually the forces required to hold the rod together will get so great that it will break apart.

#### yor_on

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##### Can we rotate something faster than the speed of light?
« Reply #3 on: 01/03/2011 17:16:58 »
It should break.

#### syhprum

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##### Can we rotate something faster than the speed of light?
« Reply #4 on: 01/03/2011 22:25:49 »
When the magnetic field rotating with a star reaches out sufficiently far that it is moving at c speed it can be considered as VLF radiation.

#### The Naked Scientists Forum

##### Can we rotate something faster than the speed of light?
« Reply #4 on: 01/03/2011 22:25:49 »