Highest RPM?

fedorfan

Does anyone know what the highest rpm in the universe is?

Ki Man

RPM? are you talking about tires or computers or what

if its speed related dont doubt the power of c

Crosson

No, but John Wheeler would jokingly discuss the maximum upper limit on horsepower (about 10^64), an engine with which would instantly rip itself into a black hole .

fedorfan

My best guess would be a turbocharger at like 180,000 rpm. I guess the universal speed limit would be the speed of light. Also, Im talking about whatever is rotating the fastest. Not pkanets or something though, I mean revolutions per minute, not year.

Crosson

This illustrates the problem with the question, because RPM on its own has no limit (as the revolving system decreases in radius). Using a radius about one meter, the speed of light limits us to an RPM of about 18 billion, so that is a safe upper limit.

Danger

My semi-educated guess is that the fastest that anyone will ever likely run across in reality would be a black hole. Since the angular momentum of the remains of the original star is conserved, those suckers can spin.

fedorfan

Yeah danger, thats probably a very close guess, although I suspect a microscopic black would be even faster.

fedorfan

Noone else knows anything?

spartinf

I'd say it is the flagellum at up to 17,000 rpm....if you look at a figure of it you'll be pretty amazed at it's complexity and sophistication

tehno

Electrons around nuclei in atoms good enough candidates?

Danger

To start with, that would be revolving, not rotating... but it doesn't count anyhow. As for the electron spin component, it isn't really spin. I think that you pretty much have to stick with macroscopic phenomena.

drboylecj

http://www.popsci.com/gear-amp-gadge...est-motor-ever

apparently the highest RPM device in existence?

Danger

Holy ****ing sheepshit! 104,000 rpms? Jeez, I thought that those 30,000 rpm satellite stabilization motors were fast. This is just outrageous.
Still, though, for non-man-made objects my money is on the black hole.

turin

How could one convince one's self that Dyson's little motor is running at such a high rpm? Even with an oscope, how would one know that the oscope isn't simply picking up "fake" electronic signals from the control circuit? I don't believe that I can hear such a high pitch. Maybe some angular momentum test?

Superstring

The maximum RPM in the universe is dependent on the radius of the spinning object.

The formula for calculating velocity of the outer edge of the "wheel" using RPM is:

[tex]\upsilon=C*RPM[/tex]

Therefore:

[tex]RPM=\frac{\upsilon}{C}[/tex]

Plugging the speed of light in for velocity (and making it an inequality to show that it has to be less than c):

[tex]RPM<\frac{c}{C}[/tex]

So the maximum RPM of an object is the speed of light divided by the object's circumference. That means the smaller the object, the faster it can spin.

Danger

Which brings us back to black holes...

diazona

Well, actually
[tex]\omega < \frac{c}{r}[/tex]
and convert to revolutions per minute. (RPM is a unit, it sows confusion to try to use it as a variable)

I got
[tex]\omega < \frac{2.86\times 10^9\,\mathrm{m}}{r}\cdot\frac{\mathrm{rev}}{\mathrm{min}}[/tex]
so... for something with radius equal to the Planck length, [itex]1.77\times 10^{44}[/itex] revolutions per minute? (If such a thing could exist, of course)