The magnetic universe begins to come into view • Hacker News Board

Re: The magnetic universe begins to come into view

#31

Post by avz » Mon, Jul 06, 2020, 10:43 PM UTC

whatshisface wrote: post #30

avz wrote: post #26

Earlier quoted context omitted.

As with the compass, the orientation of your magnetic dipole against the field is unstable, so now you need a second propulsion system for maintaining the unstable orientation of the dipole.

You don't need a second propulsion system, you could use reaction wheels[0]. [0] https://en.wikipedia.org/wiki/Reaction_wheel

Reaction wheels saturate and are therefore more suited for precise attitude control than as a source of sustained torque. Once they saturate you need to unload the accumulated momentum via some other mechanism. Thus, you do need a second propulsion system such as thrusters, light sail etc.

Re: The magnetic universe begins to come into view

#32

Post by whatshisface » Mon, Jul 06, 2020, 11:28 PM UTC

avz wrote: post #31

whatshisface wrote: post #30

Earlier quoted context omitted.

You don't need a second propulsion system, you could use reaction wheels[0]. [0] https://en.wikipedia.org/wiki/Reaction_wheel

Reaction wheels saturate and are therefore more suited for precise attitude control than as a source of sustained torque. Once they saturate you need to unload the accumulated momentum via some other mechanism. Thus, you do need a second propulsion system such as thrusters, light sail etc.

You can take the momentum back out of the wheels by rolling the magnet to the other side of the unstable equilibrium so that the wheels have to accelerate in the opposite direction to keep it steady.

Re: The magnetic universe begins to come into view

#33

Post by cthalupa » Tue, Jul 07, 2020, 1:41 AM UTC

saas_sam wrote: post #28

This has been a popular fringe scientific theory for many years under the title Electric Universe Theory. Fringe for sure, but its lead proponents tend to be real scientists referencing real, peer-reviewed literature.

>This has been a popular fringe scientific theory for many years under the title Electric Universe Theory.

They're not at all related.

>but its lead proponents tend to be real scientists referencing real, peer-reviewed literature.

They have real PhDs, some of them from respectable universities, but it's an incestuous group that has people not participate in studies so they can all peer review each other in "journals" with no real standing.

Re: The magnetic universe begins to come into view

#34

Post by peter_d_sherman » Tue, Jul 07, 2020, 5:26 AM UTC

>"One method, pioneered by the English scientist Michael Faraday back in 1845,

detects a magnetic field from the way it rotates the polarization direction of light passing through it.

The amount of “Faraday rotation” depends on the strength of the magnetic field and the frequency of the light. So by measuring the polarization at different frequencies, you can infer the strength of magnetism along the line of sight. “If you do it from different places you can make a 3D map,” said Enßlin."

Re: The magnetic universe begins to come into view

#35

Post by abrichr » Tue, Jul 07, 2020, 5:42 AM UTC

The "cosmic web" rendering (https://www.quantamagazine.org/the-hidden-magnetic-universe-...) reminds me of neurons (https://static.scientificamerican.com/sciam/cache/file/52B19...)

Is it possible that the universe is some sort of neural computation device? What could it be modelling?

Re: The magnetic universe begins to come into view

#36

Post by ecoled_ame » Tue, Jul 07, 2020, 5:56 AM UTC

api wrote: post #4

If magnetism pervades space, can interaction with these fields generate force for propulsion? These fields are weak but what about extremely powerful superconducting magnets? Even if the force is small it could add up over long periods, and since no mass is needed it would be a "massless" drive that does not violate any physical laws.

missions enabled by plasma magnet sails - https://youtu.be/0vVOtrAnIxM

everybody on 4chan /sci was talking about this a few weeks ago. seems like you can get incredible thrust from solar wind that increases proportionally with radius from the sun for constant acceleration, all with a small standard electric motor. upon cursory investigation by me it seems sorta legit. needs testing beyond earth orbit but ground tests are reported to be successful.

Re: The magnetic universe begins to come into view

#37

Post by jdmichal » Tue, Jul 07, 2020, 12:50 PM UTC

abrichr wrote: post #35

The "cosmic web" rendering ( https://www.quantamagazine.org/the-hidden-magnetic-universe-... ) reminds me of neurons ( https://static.scientificamerican.com/sciam/cache/file/52B19... ) Is it possible that the universe is some sort of neural computation device? What could it be modelling?

I'm sorry, but I have to do it...

Clearly it's calculating the ultimate question to the ultimate answer to life, the universe, and everything.

Re: The magnetic universe begins to come into view

#38

Post by heidegger » Tue, Jul 07, 2020, 7:54 PM UTC

abrichr wrote: post #35

The "cosmic web" rendering ( https://www.quantamagazine.org/the-hidden-magnetic-universe-... ) reminds me of neurons ( https://static.scientificamerican.com/sciam/cache/file/52B19... ) Is it possible that the universe is some sort of neural computation device? What could it be modelling?

"There is as yet insufficient data for a meaningful answer."