Difference between revisions of "3264: 720 Ollie"
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{{w|Tony Hawk}} tells Cueball that doing a single 360° spin causes him to land backward rather than forward. This is unexpected, since a 360° turn in the xy plane is a full revolution, meaning that it should normally return Tony Hawk to his original position rather than perform a half-rotation (normally the result of a 180° spin). As repeating this would reverse his reverse, doubling this to a 720° spin is what finally allows him to land forward. Normally, revolving 360*n degrees, for any whole number (n=0, n=±1, n=±2, etc) should leave him pointing the same range as before, but for him he returns to the same orientation if n is even, but he lands with the opposite orientation if n is odd. | {{w|Tony Hawk}} tells Cueball that doing a single 360° spin causes him to land backward rather than forward. This is unexpected, since a 360° turn in the xy plane is a full revolution, meaning that it should normally return Tony Hawk to his original position rather than perform a half-rotation (normally the result of a 180° spin). As repeating this would reverse his reverse, doubling this to a 720° spin is what finally allows him to land forward. Normally, revolving 360*n degrees, for any whole number (n=0, n=±1, n=±2, etc) should leave him pointing the same range as before, but for him he returns to the same orientation if n is even, but he lands with the opposite orientation if n is odd. | ||
| − | The caption reveals that this is because Tony Hawk is a spin-½ fermion. This explains the paradox, but is unusual because spin-½ particles are normally very small, only occurring in quantum physics rather than Newtonian physics. Since Tony Hawk is not a subatomic particle | + | The caption reveals that this is because Tony Hawk is a spin-½ fermion. This explains the paradox, but is unusual because spin-½ particles are normally very small, only occurring in quantum physics rather than Newtonian physics. Since Tony Hawk is not a subatomic particle{{Citation needed}}, it is unclear how his skateboard tricks could be described only by quantum physics. |
A '''{{w|fermion}}''' is a classification of particles (or groups of particles) whose intrinsic angular momentum (aka "spin") is half-integer multiple of the ''reduced Planck constant'', the behavior of these object's spin is described via spinors, a type of complex vector. This is in contrast to '''bosons''', whose spin is an integer multiple of the reduced Planck constant, and described by the normal Euclidean vectors you know and love. {{Citation needed}} | A '''{{w|fermion}}''' is a classification of particles (or groups of particles) whose intrinsic angular momentum (aka "spin") is half-integer multiple of the ''reduced Planck constant'', the behavior of these object's spin is described via spinors, a type of complex vector. This is in contrast to '''bosons''', whose spin is an integer multiple of the reduced Planck constant, and described by the normal Euclidean vectors you know and love. {{Citation needed}} | ||
Revision as of 14:29, 27 June 2026
| 720 Ollie |
 Title text: This discovery was key to his demonstration of regular/goofy symmetry violation, which won him gold in the theory portion of the X Games. |
Explanation
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This is one of 38 incomplete explanations: This page was created by a bunch of baryons. Don't remove this notice too soon. If you can fix this issue, edit the page! |
Tony Hawk tells Cueball that doing a single 360° spin causes him to land backward rather than forward. This is unexpected, since a 360° turn in the xy plane is a full revolution, meaning that it should normally return Tony Hawk to his original position rather than perform a half-rotation (normally the result of a 180° spin). As repeating this would reverse his reverse, doubling this to a 720° spin is what finally allows him to land forward. Normally, revolving 360*n degrees, for any whole number (n=0, n=±1, n=±2, etc) should leave him pointing the same range as before, but for him he returns to the same orientation if n is even, but he lands with the opposite orientation if n is odd.
The caption reveals that this is because Tony Hawk is a spin-½ fermion. This explains the paradox, but is unusual because spin-½ particles are normally very small, only occurring in quantum physics rather than Newtonian physics. Since Tony Hawk is not a subatomic particle[citation needed], it is unclear how his skateboard tricks could be described only by quantum physics.
A fermion is a classification of particles (or groups of particles) whose intrinsic angular momentum (aka "spin") is half-integer multiple of the reduced Planck constant, the behavior of these object's spin is described via spinors, a type of complex vector. This is in contrast to bosons, whose spin is an integer multiple of the reduced Planck constant, and described by the normal Euclidean vectors you know and love. [citation needed]
Tony Hawk is an American skateboarder credited with inventing the 720, a trick (under normal circumstances) involving two full mid-air rotations. Since Hawk invented it in 1985, larger mid-air rotations have been invented (up to 1260, three and a half rotations), and according to the comic they can have even stranger quantum properties.
The title text is a riff on the Nobel Prize-winning discovery of CP violation, (something that may have been on Randall's mind, recently, due to the prior comic's subject matter/anti-matter). The regular/goofy styles of riding a skateboard could be considered as a physical quality of the "skateboarder particle", as values of charge and parity are of subatomic ones. The X Games are a prestigious 'street-sport' event that includes competitions in skateboarding as well as other related board- and bike-disciplines. The parallel is made between being able to win a gold medal for impressive skateboarding skills (and demonstrating new tricks, in the process, as Tony Hawk has been known to do) and earning the gold Nobel Prize medal for a scientific achievements in Physics or one of the other established prize categories. So far, nobody has done both of these. But, if this comic is entirely true, perhaps Tony Hawk could be the first to do so.
Transcript
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This is one of 30 incomplete transcripts: Don't remove this notice too soon. If you can fix this issue, edit the page! |
- Tony Hawk [holding a skateboard]: Something weird I've noticed is that if I do a 360 ollie, I land backward. I have to do a 720 to land going forward.
- [An illustration, above the heads of Tony Hawk and Cueball, depicts Tony Hawk doing two 360-degree turns on a skateboard]
- Caption: Tony Hawk discovers that he's a spin-½ fermion.
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Never really understood skateboards myself 216.25.182.141 03:00, 27 June 2026 (UTC)
- That's okay. I never really understood human-scale spin-½ fermions. 2603:8081:9700:1224:0:0:0:2 03:18, 27 June 2026 (UTC)
Early footage of Tony exploring rotational symmetries: The Loop (2001) https://www.youtube.com/watch?v=PLC1V22Y7iY Note that he needs to go around the loop twice before he can return to his original orientation and land the trick. 86.23.176.63 03:39, 27 June 2026 (UTC)
Riding "regular" vs "goofy" just means which foot is placed at the front, it has no real effect on what you can or can't do so you could describe it as a "symmetry" similar to symmetries in physics. Discovering a way to break that symmetry would, in theory, be an important discovery to people who cared about theoretical skateboarding. Undergroundmonorail (talk) 04:37, 27 June 2026 (UTC)
- I think the parallel is to the way that total 'spins' and other things are (or perhaps notably aren't) conserved across various feynman diagrams, and your footedness is a state of the system (you can change it, mid-trick, but then the switch becomes part of thst trick) like the charge is a part of any given interaction/combination/decomposition of particles. Obviously any southpaw (southpad?) skater may bias towards or away from certain normal/goofy stances that a standard contrmporary may bias oppositely to, but it sounds like the comic is suggesting something even more fundemental about differences in that (e.g.) left-turns in both modes (by all types of rider) are statistically tighter than right-turns by exactly flip-matched individuals. Or something like that. (Taking this complete hypothetical further, the studies regarding this need to be done in both north and south hemispheres, to rule out it simply being a skateboard-detected consequence of the Coriolis force! While a single X Games is not enough to check this, I believe subsequent events have been held in opposing hemispheres. ;p )
- Of course it's analogy-stretching (both the comic and myself), but this is xkcd. Stretching of analogies (both within the range of Hooke's law and even beyond the elastic limit, whether under tension, compression, torsion, etc) is what both Randall and ourselves do. ;) 82.132.238.177 11:10, 27 June 2026 (UTC)
"Tony Hawk is not a subatomic particle [citation needed]" XD 2401:4900:ADC9:33ED:3028:A249:ED24:CD91 07:00, 27 June 2026 (UTC)
Nevertheless Tony Hawk is awesome and can do anything a subatomic particle can do. Alas, the description (why a fermion differs from a boson) is not dumb enough for me to understand, tho. Dúthomhas (talk) 07:46, 27 June 2026 (UTC)
- I think we need to properly investigate the abilities of the supersymmetric version of Tony Hawk. We do know that he's capable of walking long distances with fridges, can play tennis, etc, but we're still some way from a direct comparison under a Grand Unified Theory. 82.132.238.177 11:52, 27 June 2026 (UTC)
I must admit, when I started reading the comic I was initially thinkingnit was going to be something to do with the tendency of objects spun around a minor axis to also flip (unbidden) around their major axis. Remote controls, table-tennis bats, anything where a 360° flip is obviously happening but lands back in your hand 180° rotated, longitudinally (buttons now faced down, red/black paddle surfaces inverted, etc), regardless(/specificallly) of how carefully you try to do a perfect one-axis spin of tbis manner. — So, now I'm wondering, is that the underlying reason for the quantum-mechanical 'half-spins'? Whereby an unrelated (and not understood/hidden-variable) long-axis spin exhibits an apparent half-spin as a precessionary artefact? Or it's 'just' a more standard topological rotational symmetry of ½ made 'real'. (Of course I know that 'spin' isn't anything much like classical physics spinning, like quarks don't have colours, just everything else.) 82.132.238.177 11:52, 27 June 2026 (UTC)
Maybe its been mentioned but a real world example of a macroscopic spin 1/2 system is where the object is tethered to a fixed point and the tether can bend but not twist. Simple example is holding a coffee cup in your hand (I can't actually do this, my arm isn't flexible enough) you can rotate the cup 360 degrees over your arm but your arm gets kind of twisted, if you then rotate the cup under your arm your arm untwists and you get back to the original position. I'm sure I saw someone demonstrate this in a lecture and I thought I could do it but can't seem to make it work.
Anyway my point is you get a macroscopic system where the cup needs to rotate 720 degrees to return the system to its starting point.
Also when using quaternions to handle rotation in 3D game design they seem to define a spin 1/2 system but you just have to deal with it, its just numbers
80.229.249.36 13:05, 27 June 2026 (UTC)
As I understand it, some new symmetries originally identified in the two-Higgs-doublet model, also known as 𝑟0-symmetry, have been referred to as the goofy symmetry based on the names of the authors. 49.194.177.67 13:15, 27 June 2026 (UTC) Add comment
