How to build an antigravity device | Hacker News Reader

How to build an antigravity device

chrispacia.wordpress.com

13 pointswunderg22 comments

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 a small rock.

In think the point was sightly different - roughly that as a particle approaches the speed of light, its 'inertial mass' approaches infinity (as it requires more energy to speed it up). Unfortunately this 'inertial mass' is unrelated to gravity.

A small rock near a larger rock, to be fair. Still not very effective.

Yes to me it doesn't any more realistic than Bob Lazar's story that he quotes, just more convoluted.

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.

It's hard to tell whether some of the comments are serious, trolling, or the product of deranged Markov Chains.

my money is on markov chains, no human is _that_ bad at grammar

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.

Yes, that's what I was about to write: a “superconducting ferro-superfluid” is, as I understand it, an oxymoronic self-contradiction.

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 wheel yank in the direction of flow. So long as energy could be added back to the superfluid to accelerate its circulation, it could be extracted again and again with laser zaps to do work. (How many ways can a superfluid circulate inside a hollow torus?)

Why would it be cool?

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.

Because it would do work in a novel way. It could be used to levitate a spaceship, for example.

No, it wouldn't. It would cause a torque as the momentum from the fluid is transferred to the torus. It would not cause a lift. There's no overall momentum change.

It's basically a gyroscope, albeit with quantized vorticies.

An external magnetic field could be used to levitate an object. But that's not novel.

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 doing anything to break conservation of momentum.

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?

It still has inertia, and as you point out it has the added disadvantage of having no internal structure to help hold it in place.

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?

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.

The first problem I thought of is that as the speed goes up, the centripetal force causes the pressure to increase. At some point there will be a transition from liquid to solid. Eg, for ⁴He, and if I read the phase diagram correctly, that's at 25 bar.

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."

so, I didn't quite get the connection between element 115 and superferrofluids/the warpdrive theory...is element 115 a superferrofluid? or did that first part of the article have nothing to do with the rest of it?

The latter. He was just citing another conspiracy theory of how to create a gravity engine / warp drive that had become more relevant with the actual discovery of E115.

Sorry, but this article is not even as convincing as Bob Lazar himself. I love that guy. One of the biggest and most genuine-sounding charlatans in the UFO community, but a hell of a lot of fun to listen to.

I think the issue with very high speed centrifuges is much more about the high centrifugal force than it is about friction.

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