/sci/ - Science & Math » Thread #12007368

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Anonymous Fri 14 Aug 12:27:50 2020 No.12007368 View Reply Original Report

Quoted By: >>12007441 >>12007448 >>12007463 >>12007689 >>12007702 >>12008281 >>12008338 >>12009617 >>12009639 >>12009652 >>12009900 >>12011623 >>12013645

This doesn't look like it "should" be possible, but it also looks like it's the case.
Why?
Why is it that it looks like it shouldn't be possible, and why is it possible?

Anonymous

Anonymous Fri 14 Aug 2020 12:28:52 No.12007371 Report

Quoted By:

Because it is.

Anonymous

Anonymous Fri 14 Aug 2020 12:55:45 No.12007441 Report

Quoted By:

>>12007368
The rotation group is fucked up

Anonymous

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Anonymous Fri 14 Aug 2020 12:57:25 No.12007444 Report

Quoted By: >>12009900

Anonymous

Anonymous Fri 14 Aug 2020 12:59:02 No.12007448 Report

Quoted By: >>12007462

>>12007368
Because rotation by 4pi is equivalent to no rotation

Anonymous

Anonymous Fri 14 Aug 2020 13:06:54 No.12007462 Report

Quoted By: >>12009575 >>12015549

>>12007448
But rotation by 2pi isn't?

Anonymous

Anonymous Fri 14 Aug 2020 13:07:14 No.12007463 Report

Quoted By: >>12007467

>>12007368
I mean why not? if it works it works right

Anonymous

Anonymous Fri 14 Aug 2020 13:08:17 No.12007467 Report

Quoted By:

>>12007463
this

Anonymous

Anonymous Fri 14 Aug 2020 15:15:06 No.12007689 Report

Quoted By:

>>12007368
because $\pi_1(SO(3)) \cong \mathbb{Z}/{2\mathbb{Z}}$

Anonymous

Anonymous Fri 14 Aug 2020 15:23:30 No.12007702 Report

Quoted By:

>>12007368
As Ike Chuang once said, we must show reverence for the majesty of SU(2).

Anonymous

Anonymous Fri 14 Aug 2020 16:43:00 No.12007837 Report

Quoted By: >>12008351

Another thread about spin groups? Is this a new meme?

Anonymous

Anonymous Fri 14 Aug 2020 19:10:44 No.12008281 Report

Quoted By: >>12008286 >>12008338

>>12007368
I think it only "feels impossible" because one imagines a rubber that in reality can't be turned around and axis forever

Anonymous

Anonymous Fri 14 Aug 2020 19:13:23 No.12008286 Report

Quoted By:

>>12008281

But it isn't. If you look closely (easiest on the ribbon coming from right) it loops over the cube for one rotation and then under for the alternating rotations. The net effect is no twisting over time.

Anonymous

Anonymous Fri 14 Aug 2020 19:30:51 No.12008338 Report

Quoted By:

>>12007368
this has been used to allow fluid flow between rotating components
>>12008281
it works IRL, you can test this out with some ribbon and a disk

Anonymous

Anonymous Fri 14 Aug 2020 19:34:17 No.12008351 Report

Quoted By:

>>12007837
Its just iq gating and its effects in action

Anonymous

Anonymous Sat 15 Aug 2020 01:52:56 No.12009495 Report

Quoted By:

It becomes very obvious/intuitive how it works when you focus on only two rods at once.

Anonymous

Anonymous Sat 15 Aug 2020 02:18:41 No.12009575 Report

Quoted By:

>>12007462
Lrn2spinstructure

Anonymous

Anonymous Sat 15 Aug 2020 02:30:01 No.12009617 Report

Quoted By: >>12009629 >>12009649 >>12016398

>>12007368
you can try it irl
take a cup upright in the palm of one of your hands, rotate it once over your head so your arm is a bit twisted, then the second time under your armpit so that the arm is untwisted again. all while holding the cup upright.
result: the cup made 2 full rotations and your arm is still attached.

Anonymous

Anonymous Sat 15 Aug 2020 02:36:22 No.12009629 Report

Quoted By: >>12009765

>>12009617
Is that at all related to why quaternions have "double cover" of rotations?

Anonymous

Anonymous Sat 15 Aug 2020 02:41:30 No.12009639 Report

Quoted By:

>>12007368
looking at the bottom-screen-to-top-of-cube ribbon makes me want to call bullshit on this.
The bottom should carry on getting twisted.
And yet, all I see is just the purple side facing me, completely fucking with my brain, raw and with no lube, in the process
Fuck, I'm a simpleton.

Anonymous

Anonymous Sat 15 Aug 2020 02:47:32 No.12009649 Report

Quoted By: >>12009765

>>12009617
Can you provide a visual because I'm way too retarded to understand what you mean

Anonymous

Anonymous Sat 15 Aug 2020 02:48:47 No.12009652 Report

Quoted By:

>>12007368

it looks possible to me.
try looking at it.

Anonymous

View Same Google iqdb SauceNAO rotating_cup.png, 705KiB, 920x1345

Anonymous Sat 15 Aug 2020 03:28:43 No.12009765 Report

Quoted By: >>12009898 >>12010041 >>12011611

>>12009629
ye
>>12009649
see pic, taken from Bredon's "Topology and Geometry"

Anonymous

Anonymous Sat 15 Aug 2020 04:22:16 No.12009898 Report

Quoted By:

>>12009765
This is kung fu

Anonymous

Anonymous Sat 15 Aug 2020 04:24:31 No.12009900 Report

Quoted By:

>>12007368
>>12007444
NONE OF THE LINE CROSS

Anonymous

Anonymous Sat 15 Aug 2020 04:25:27 No.12009904 Report

Quoted By:

topologists are dark wizards

Anonymous

Anonymous Sat 15 Aug 2020 04:40:58 No.12009938 Report

Quoted By:

Is all rotation in higher dimensions a combination of some planes? For example you can rotate square in its only plane. If you rotate a cube, you choose a certain plane with an axis going through it and rotate the cube with it, but not "three-dimensionally". If you have a 4D tesseract, you can independently rotate it in planes fully orthogonal to each other. But does it stay all the same in the higher dimensions? Like if the number is even, you have dimension/2 independent rotations and if odd, one dimension is unused. Or is there something more complex up there?

Anonymous

Anonymous Sat 15 Aug 2020 05:53:54 No.12010041 Report

Quoted By:

>>12009765
yoooo
i learned about this when i first got into quaternions because of gimbal lock. it freaks me out. so cool.

Anonymous

Anonymous Sat 15 Aug 2020 18:49:24 No.12011598 Report

Quoted By:

quit posting this weinstein shit.
give it a fucking rest.
the guy is a fraud.

Anonymous

Anonymous Sat 15 Aug 2020 18:55:10 No.12011611 Report

Quoted By: >>12011671 >>12013661

>>12009765
This is anatomically impossible. I just tried it and hurt my shoulder.

Anonymous

Anonymous Sat 15 Aug 2020 18:58:29 No.12011623 Report

Quoted By:

>>12007368
You nailed gravitoelectromagnetism.
>Join us
https://www.thunderbolts.info/wp/

Anonymous

Anonymous Sat 15 Aug 2020 19:12:59 No.12011671 Report

Quoted By:

>>12011611
>This is anatomically impossible.
For you.

Anonymous

Anonymous Sun 16 Aug 2020 05:46:19 No.12013645 Report

Quoted By:

>>12007368
Are there any videos of a working physical model?

Anonymous

Anonymous Sun 16 Aug 2020 05:52:08 No.12013661 Report

Quoted By: >>12013709 >>12013746

>>12011611
https://youtu.be/rC0jAICfNwc?t=25

Anonymous

Anonymous Sun 16 Aug 2020 06:08:16 No.12013709 Report

Quoted By:

>>12013661
this shit genuinely feels like forbidden knowledge to me

Anonymous

View Same Google iqdb SauceNAO d1388161.jpg, 278KiB, 800x600

Anonymous Sun 16 Aug 2020 06:20:39 No.12013739 Report

Quoted By: >>12014972

Stretch your arm out in front of you with the palm out of your hand down.
Now try and turn the palm upwards using only elbow movements.

Anonymous

Anonymous Sun 16 Aug 2020 06:22:40 No.12013746 Report

Quoted By:

>>12013661
Thank you for giving me something new today!

Anonymous

Anonymous Sun 16 Aug 2020 16:35:02 No.12014972 Report

Quoted By:

>>12013739
well I guess it's a Sieg Heil to you my friend

Anonymous

Anonymous Sun 16 Aug 2020 20:10:47 No.12015549 Report

Quoted By:

>>12007462
not for electrons & other spin-1/2 particles

Anonymous

Anonymous Mon 17 Aug 2020 01:04:16 No.12016398 Report

Quoted By: >>12016431

>>12009617
I tried doing this and now my arm is all fucked up. And I broke the cup, which was a priceless family heirloom. Thanks a lot!

Anonymous

Anonymous Mon 17 Aug 2020 01:29:24 No.12016431 Report

Quoted By:

>>12016398
try it with your neck

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