Editing 2882: Net Rotations

{{comic
| number    = 2882
| date      = January 17, 2024
| title     = Net Rotations
| image     = net_rotations_2x.png
| imagesize = 318x477px
| noexpand  = true
| titletext = For decades I've been working off the accumulated rotation from one long afternoon on a merry-go-round when I was eight.
}}

==Explanation==
This is another one of [[Randall|Randall's]] [[:Category: Tips|Tips]], this time a Spacetime health tip. 

This comic may refer to a thing that some people with {{w|OCD}} do, which is to spin around to get rid of "net rotations," hence the title of this comic. [[Cueball]] (perhaps representing [[Randall]]?) takes this one step beyond the typical person with OCD - he calculates the net rotations each day and spins around at the end of the day to cancel this out. In this case, he would be spinning left 17 rotations to return to zero.

The offered reason for the necessity to do this is a physics joke: the reference to spacetime and to one's "worldline" has to do with relativity and the {{w|Einstein-Cartan theory}}, which is an extension of Einstein's general relativity. The theory suggests a coupling between the intrinsic spin of elementary particles (fermions) and the torsion of spacetime, and this comic appears to humorously extrapolate this idea to even supermolecular structures like a human, telling readers to "cancel out your accumulated turns at the end of each day to avoid worldline torsion", where in reality, it is highly unlikely the spin on such a large scale would cause any torsion in anyone's worldline, or their path traced by a particle or observer in spacetime.

A mobile device with position and orientation sensing might be able to keep track of one's net rotations, eliminating the need for calculations. One would need only to do one's spinning while monitoring the device to see when it returned to zero.

The caption suggests that this is healthy and necessary/highly recommended to do this. However, most people don’t, and most people are still OK.{{Citation needed}} In fact, xkcd's own characters are perfectly OK with [[162: Angular Momentum|accumulating net rotations]] and [[2679: Quantified Self|similar topological excesses]].

Possibly a reference to the 1966 novel, [//archive.org/details/revolvingboy0000frie The Revolving Boy] by {{w|Gertrude Friedberg}} whose protagonist suffered from being out of sync depending on the number of turns he was forced to make in his everyday life.

The title text mentions that Cueball was on a {{w|merry-go-round}} when he was eight and he accumulated so many rotations that he's still trying to counter these rotations to this day.

==Transcript==
:[Cueball is rotating around himself with only one foot on the ground, the other leg raised and bend above the ground and with his arms crossed in front of his chest. There are five circular curves around Cueball from head to legs to indicate this rotary motion. He rotates in front of a whiteboard. On the left of the board there are two vertical helix-like curves going from near the top to the bottom. They are crossing over each other at five points, the first four crossings close to the top, and then one near the bottom. Next to this there are ten rows of illegible scribbles, then a line, then another row of scribbles then a line and at the bottom a row of scribbles which is circled in. There is a large thought bubble above Cueball to indicate that he is thinking to himself while rotating in front of his calculations on the whiteboard.]
:Cueball (thinking): ...and three lefts for going down the stairwell at work, two rights from cloverleaf interchanges, minus one for the Earth's rotation...
:Cueball (thinking): Okay, that's a net of 17 right.

:[Caption below the panel:]
:Spacetime health tip: Remember to cancel out your accumulated turns at the end of each day to avoid worldline torsion.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Astronomy]]
[[Category:Physics]]
[[Category:Tips]]