
Fastest rotating man-made object created - jonbaer
http://phys.org/news/2013-08-fastest-rotating-man-made.html
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ISL
Very cool! Small fast-spinning objects have practical use as 'spinning rotor
pressure gauges'. They're the true pressure transfer standard at very high
vacuum. You can buy them.

Beams et al. were spinning steel ball bearings at megahertz in the sixties.
(For the fourier-inclined, the readout uses a cool trick. They bounce light
off the bearing and track the frequency of the ~50th harmonic, increasing the
size of the frequency shift.)

600 million RPM is 10 MHz. Beams reached at least 1 MHz, and their circuitry
could do 8.

[http://rsi.aip.org/resource/1/rsinak/v33/i2/p151_s1](http://rsi.aip.org/resource/1/rsinak/v33/i2/p151_s1)

Thank you, OP, it's been fifty years since this field has seen a change.

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delluminatus
Made me want to look up dental drills. Wikipedia says they can spin up to
800,000 RPM.

Never would have occurred to me that the fucking drill in my mouth was
rotating 10,000 times a second.

~~~
grinich
Those dental drills are powered by an air turbine, though.

Dyson (notable for their vacuums) actually have done a bunch of work
pioneering high-speed electric motors. The Dyson Digital Motor is awesome and
runs at +100k rpm. They're used in the "Airblade" hand dryer.

[http://www.dyson.com/vacuums/ddm.aspx](http://www.dyson.com/vacuums/ddm.aspx)

~~~
mercuryrising
The dyson motor doesn't show any sizes, but 100k spindle motors are not
impossible to make. They're commonly used for PCB production

> Some of the high performance spindle motors used on large-size mass
> production PCB drilling machines are capable of running at 200,000 rpm or
> higher.

from
[http://www.mitspcb.com/edoc/spindle.htm](http://www.mitspcb.com/edoc/spindle.htm)

~~~
grinich
It's surprisingly large:
[https://www.youtube.com/watch?v=6kcGltYWz3k](https://www.youtube.com/watch?v=6kcGltYWz3k)

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ctdonath
In hope of finding relativistic effects, I calculated the outer edge of the
spinning object travels about 7.85 m/s. Sigh...

~~~
jlgreco
I was hoping I could find something natural that spun faster, and thought that
neutron stars might just be a candidate. Nope, not even close: _" The star
rotates 716 times per second - faster than some theories predict is possible"_
[http://www.newscientist.com/article/dn8576-fastspinning-
neut...](http://www.newscientist.com/article/dn8576-fastspinning-neutron-star-
smashes-speed-limit.html#.Uh5A03eBW2k)

~~~
lutusp
> I was hoping I could find something natural that spun faster ...

A bit unrelated to your comment, but the original experimenters could have
spun a buckyball instead of a sphere of calcium carbonate and gotten much,
much higher rotational velocities. I hope they think of this.

~~~
dalke
Can you kindly explain how even a UV laser, with a wavelength of about 200 nm,
can apply enough torque on a buckyball about 1.1 nm across?

My first thought was that the EM field would be essentially uniform, so what
you propose wouldn't be possible. What am I missing?

~~~
lutusp
> Can you kindly explain how even a UV laser, with a wavelength of about 200
> nm, can apply enough torque on a buckyball about 1.1 nm across?

No chance. But it turns out there are larger fullerenes:

[http://en.wikipedia.org/wiki/Fullerene#Other_buckyballs](http://en.wikipedia.org/wiki/Fullerene#Other_buckyballs)

But as it turns out, the larger fullerenes aren't as strong as C60, so my
original idea probably wouldn't represent any easily achieved advantage.

~~~
dalke
As jlarocco and others point out, based on astronomical evidence, we know that
C60 buckyballs are plenty strong enough to rotate at a much higher speed than
this macroscopic experiment:

For example, "Hydrogenated fullerenes and the anomalous microwave emission of
the dark cloud LDN 1622"
(www.iac.es/folleto/research/preprints/files/PP06009.ps ) says:

> The recent detection of anomalous microwave emission (5–60 GHz) in LDN 1622
> by Casassus et al. can be explained as the result of electric dipole
> radiation from hydrogenated fullerenes. The bulk of the emission (10–30 GHz)
> appears to be associated with 60–80 carbon atoms fulleranes with a degree of
> hydrogenation of C:H ≈ 3:1. ...

> The emissivity of fulleranes with more than 240 atoms are already two orders
> of magnitude smaller than that of the C60 hydride and peaks at a frequency
> of ∼3 GHz, far below the frequencies relevant to the anomalous emission
> detected in the cloud.

It looks like C240 should be able to handle 1GHz rotational speeds without a
problem.

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deletes
I hate it how phys.org has apparently randomly placed links in the text
pointing to the same site, giving no extra explanation about the linked word,
just a list of articles vaguely related.

~~~
jemka
Could not agree more. It's unfortunately a common (and obviously automated)
way to get page views. Extremely aggravating.

Put a list of related articles at the end. But don't underline terms like
"radiation pressure" and expect me be happy when you don't immediately tell me
what that is. And especially don't put the article I'm reading as the first
result.

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lutusp
Quote: "To do this they manufactured a microscopic sphere of calcium carbonate
only 4 millionths of a metre in diameter."

Calcium carbonate? How disappointing. Maybe they can be persuaded to spin a
buckyball instead -- it would tolerate much higher centripetal forces.

~~~
mtdewcmu
It seemed like an odd choice to me at first, but they probably chose calcium
carbonate because of its ability to polarize light:

[http://www.daviddarling.info/encyclopedia/P/polarization.htm...](http://www.daviddarling.info/encyclopedia/P/polarization.html)

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toblender
Is there anyway for the generate electricity?

Example: They stick a tiny magnet in there, have it rotate super fast
surrounded by cooper or something.

~~~
jd007
Why would this generate electricity? The energy put in to spin the ball must
be higher than what you get out of it.

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alttab
Just to be sarcastic for a second about this title: "Fastest rotating man-made
object created"

My answer: "No shit"

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DanielBMarkham
This is very interesting. I'd like to see followup work done with a charged
sphere and even a Bose–Einstein condensate, if possible.

As a layman, this looks to me like a really neat way to ask questions and
learn more about the nature of reality. Cool stuff.

~~~
ISL
People do the analog with BECs. Look up BECs and, perhaps, Gauss-Laguerre
beams, though there are other ways to rotate them.

Like superfluids, BECs don't rotate in the usual way. Instead, vortices are
quantized and the vortices pack.

[http://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensat...](http://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensate#Vortices)

See the 'vortex lattice' in this photo:

[http://ucan.physics.utoronto.ca/News/report.2006-07-06.39490...](http://ucan.physics.utoronto.ca/News/report.2006-07-06.3949014531/view)

