relativistic centrifuge

[IronWing]

I asked this over on ATOT but no one replied so I thought I'd ask over here where all the smart folks hang out...

What happens if you build a centrifuge, a really nice centrifuge, and start cranking it up so that the outside edge starts getting into the 0.01=>0.1=>0.9 c range? The outside edge should be experiencing time dilation relative to points closer to the center, sort of a experiential time gradient along the radius.

Might be able to conduct some interesting chemical experiments where kinetics limit some reactions and not others but can be controlled by position on the radius.

Am I correct in my thinking?

 

[CycloWizard]

Very interesting idea... Using this idea for reaction engineering could allow you to react the less dense species for longer times, thereby increasing selectivity. I'm not too familiar with the time scales of relativity, but to offer any real benefit, the retention time difference would have to be significant (i.e. a large centrifuge).

 

[So]

huh. Interesting idea. I suspect you'd see a warping effect in the rotors, time dialating more as radius increased. Imagine that.

 

[Heisenberg]

Hmm...that is interesting to think about. I would naively agree that the outer points on the centrifuge would experience a larger time dilation effect since they would have a larger relative velocity. Also, the mass would increase the farther out on the arm you went. Lorentz contraction would occur, although not in the radial direction of the arm since it would always be orthogonal to the velocity, but the arm would appear thinner as you went out (I think). The other thing to consider is how the centripetal acceleration would be affected. I'm really not familiar with angular relativistic motion and the complications that occur but it's fun to think about.

 

[iwantanewcomputer]

holy crap, that opens up so many possibilities. the scale would have to be rediculous(like earth sized even for long term reactions, i think flying a clock around the world only loses a few billionths of a second)
also i think the energy needed to spin it up would be immense cause of the scale and the relatavistic mass increasing

 

[Cattlegod]

at 10% the speed of light the outside of the unit would have to travel at 67,000 mph. It would have to be done in a vacuum.

if the centrifuge had a 100 foot radius (keep it semi practical for an on earth application) then the centrifuge would have to spin at 13,000 RPM. (hope i didn't goof my calculations, no paper)

imagine a football field spinning at 13,000 RPM. yikes.


and that is just to get 10% the speed of light, i couldn't imagine ramping that up. and the size it would have to be to withstand the forces. if something were to happen, it would probably leave a nice crater in the place where it was established.

 

[alpha88]

I've thought of this, but not done any math - one thing to consider is that since the object is accelerating (constantly) there will be a whole lot of weird things. Most of our math / examples are done in inertial frames (with discontinuities of acceleration)

 

[IronWing]

I did a quick search on existing centrifuges to find out how far the current models are from something that might show effects. The fastest commercially available model I could find on my not-too-lengthy search is a 130,000 rpm centrifuge yielding a linear velocity of ~0.00000681 c at a cost of ~US$30K. Keeping in mind that this a centrifuge designed for easy access, quick startup and slowdown, and designed to hold disposable test vials I imagine a purpose built centrifuge would be able to achieve much higher linear velocities.