Okay, so I read on some site that when they cooled Helium-4 to almost absolute zero and forced it through tiny holes in an effort to accelerate or pressurize the liquid it whistled (something about quantum). This, the article further explained, was useful because it could be used to make super accurate gyroscopes (with little or no moving parts).
Got a few questions:
Why were they trying to squirt super cooled helium through tiny holes in the first place? Obviously, they were trying to do something. You don’t do something like this by accident.
Why is it that everything does such cool stuff when it’s at or near absolute zero? Absolute zero seems to me some kind of magical place kind of like warp factor nine.
Quantum?
Why does whistling helium imply a better gyroscope?
There’s an explanation here. I don’t understand it, but at least it covers some of the relevant properties of superfluids.
Yesterday’s space.com article succintifies the earlier explanation into total incomprehensibility:
Since you don’t cite the article, I’m not certain exactly what the observed result was or how it is applicable to gyroscopic motion, but as far as why helium does “cool stuff” when it is near absolute zero I give you this. Essentially (and for very complex reasons that people win the Nobel prize for explaining), helium does some very flukey things at about 2 Kelvin (in a phase referred to as He(II)). Specifically, it acts without regard to any frictional forces (so it flows through orifaces without the “capillary effect” like a ), it refuses to transition into a solid, and it demonstrates quantum (stepwise, frictionless) effects at the macroscopic level.
As for its capability as a gyroscope, a fluid that shows a zero net flow around a loop means that no energy is lost in rotation around a fixed axis. (This is a result of frictionless "superfluidity.) When the axis rotates, the effect (change of momentum) can be measured and hence the amount/rate of rotation can be determined to a high degree of accuracy, without having to account for friction loss at bearings or frequency shifts in a moving photon or any other error. The “whistle” they are refering to is (I imagine) just a standing wave by which to measure the flow rate of the fluid though the oriface.
If you can cite the specific article, I’m sure some of our better (and at this point of the evening, less intoxicated) minds can provide a more adept answer to your question.
