11–20 of 23 posts
a superfluid flows with zero viscosity, that means if we were to put it into some kind of centrifuge and spin it, it would not slow down due to friction. If it never slows down due to friction, in theory, that implies we should be able to accelerate a superfluid to the speed of light. ah ah ah ah nope.
It doesn't sound right to me either, but I have a hard time explaining to myself why it wouldn't maintain it's velocity.
I'm sorry, that was a super disappointing reveal. "However, we would expect the centrifuge to gain mass (and hence generate an increasing gravitational field) as fluid spins up to relativistic speeds. Hello warp drive! Oh, and you’re welcome." Congrats, E=mc², you've collected a large amount of energy in a small area and created a gravitational field. You've now reached the space travel and anti-gravity technology of…
Why do you need a superfluid? It sounds like all you need is disc in a vacuum that you suspend/rotate like the armature of a motor. Until, of course, it gets nowhere near the speed of light because the limiting factor to spinning something fast isn't friction, it's the required centripetal force to keep it in one piece. And assuming you could solve that by making the spinning thing out of unobtanium, you're still not…
But is that not why he is using a fluid? A fluid does not have intermolecular bonds that need to overcome the centripetal force, so it shouldn't be a problem?
Put a plate in the center of a turntable and pour some water into it. Now rotate the turntable, slowly accelerating. What happens to the water?
I think you guys are overlooking the most obvious flaw, in that a "superferrofluid" should be impossible to manufacture, as a "ferrofluid" by definition must have some amount of intermolecular bonding, where as a "superfluid" cannot have any at all.
a superfluid flows with zero viscosity, that means if we were to put it into some kind of centrifuge and spin it, it would not slow down due to friction. If it never slows down due to friction, in theory, that implies we should be able to accelerate a superfluid to the speed of light. ah ah ah ah nope.
Could you explain why not? It doesn't sound right to me either, but I have a hard time explaining to myself why it wouldn't maintain it's velocity.
I searched for "rotating superfluid helium" and found http://physicsworld.com/cws/article/news/2018/feb/07/unexpec... , which is a summary of https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.01... . It says that there is friction, perhaps caused by "quasiparticles that become trapped within the cores of vortexes. As the vortexes accelerate, the quasiparticles gain energy, which they can then dissipate to their surroundings in the form of friction."
I'm sorry, that was a super disappointing reveal. "However, we would expect the centrifuge to gain mass (and hence generate an increasing gravitational field) as fluid spins up to relativistic speeds. Hello warp drive! Oh, and you’re welcome." Congrats, E=mc², you've collected a large amount of energy in a small area and created a gravitational field. You've now reached the space travel and anti-gravity technology of…
My understanding of a warp drive (Alcubierre drive) is that it contracts space in front of the ship while expanding space behind it. I don't understand how increasing a gravitational field locally is meant to achieve any of that.
What would be cool is a circulating superfluid, say inside a hollow torus, that could be made frictional on command at a chosen spot on the interior surface of the torus. Imagine holding the torus like a steering wheel. Inside, the superfluid is rapidly circulating. Say when a laser zaps a region where fluid and container touch, the superfluid becomes slightly frictional in that spot. One would feel the steering whee…
We can do something like that already with current flowing in a circle in a superconductor. Resistance corresponds to friction. In the worst case you get a quench and all of the stored angular momentum results in a torque that breaks your machine.