most sensitive torque sensors ever made.

https://phys.org/news/2020-01-sensitive-torque-device-built.html

Any idea just how these things work?

@sonhouse
No idea, however, it reminded me of a spinning fridge. If you could spin your food at 99.95% light speed, its time would slow down so much that a sandwich would stay warm n fresh for a year.

@bunnyknight
Be hard to open though😉

@sonhouse said
@bunnyknight
Be hard to open though😉

I'm sure those minor details could be ironed out in no time.

@bunnyknight
Of course the iron would have to be going the same rate.

@sonhouse
So if you have a disk spinning so that the edge is going at 99.9999% lightspeed, how would the huge time differential affect the overall molecular structure? Or would it affect gravity?

@bunnyknight
Well first off, it would have been torn apart before it reached a hundred thousand RPM but other than that pesky detail......

@sonhouse said
@bunnyknight
Well first off, it would have been torn apart before it reached a hundred thousand RPM but other than that pesky detail......

That's obvious. But let's assume it's strong enough not to tear apart.

@sonhouse said
https://phys.org/news/2020-01-sensitive-torque-device-built.html

Any idea just how these things work?

It is explained in the article... you measure the variation in spedd in relation to a force which exerts torque which in turn slows down the particle. And they talk about 300*10^9 rpm you can do such rotational speed only for very small particles.


The values are of course exciting.

@Ponderable

Torque rendering as in a magnetic field?

@bunnyknight said
@sonhouse
So if you have a disk spinning so that the edge is going at 99.9999% lightspeed, how would the huge time differential affect the overall molecular structure? Or would it affect gravity?

The circumference of the disc would undergo length contraction. Since the interior is spinning at a lower rate and is stationary at the centre the disc would be compressed - assuming that we've somehow switched off the absolutely monstrous centrifugal forces. If it's massive then you'd get frame dragging effects. It's a little difficult to say as the situation is unphysical due to the requirement that it doesn't fly apart easily.

@deepthought said
The circumference of the disc would undergo length contraction. Since the interior is spinning at a lower rate and is stationary at the centre the disc would be compressed - assuming that we've somehow switched off the absolutely monstrous centrifugal forces. If it's massive then you'd get frame dragging effects. It's a little difficult to say as the situation is unphysical due to the requirement that it doesn't fly apart easily.

Many thought experiments are impossible in today's real world, yet they can still be useful.
So if this spinning disk shrinks via relativity, it should spin even faster, however, it's mass should also increase, thus negating the rotation speed. And what effect would it have on the space-time fabric? I wonder if anyone has thoroughly analyzed what would really happen in this scenario, perhaps with a simulation on a supercomputer.

@bunnyknight
Yes, spinning neutron stars for instance. Generating frame dragging which BTW was the subject of a 40 year long experiment culminating in a satellite that directly measured frame dragging right here in Earth orbit. It took that long for technology to catch up with the original thought experiment that ATT was thought to be not measurable but 40 years later it was shown to be a fact and the tiny frame dragging was actually measured in a sat.

It was called Gravity Probe B:

https://en.wikipedia.org/wiki/Gravity_Probe_B