# 2805: Global Atmospheric Circulation

 Global Atmospheric Circulation Title text: Refs generally say that you can exercise enough altitude control to avoid the ground, but if you start strategically choosing air layers to steer yourself, that's traveling.

## Explanation

In this comic, Beret Guy shows Cueball a trick basketball shot. However, the trick is that he can use atmospheric circulation to roam across the globe, eventually drifting back over the basketball net after the passage of 1500 years. Of course, a normal human being would be long dead after that time[citation needed], and a normal balloon would have lost all of its helium. But, given Beret Guy's special abilities, it is presumed that he could indeed live that long. After waiting for several frames, Cueball is confused at Beret Guy drifting away under a balloon, and thus leaves the basketball court. In addition, Cueball would not be able to witness Beret Guy's shot anyway, as Cueball would be long dead. Beret Guy probably doesn't realize this at all, considering how naïve he is.

The Albuquerque box effect: southerly winds at low altitudes and northerly winds at high altitudes allow balloonists to change direction by adjusting their altitude

The title text refers to the fact that players in this atmospheric circulation basketball game are allowed to maneuver to avoid falling back to the ground, but once players begin to exploit different windspeeds at different altitudes, they are "traveling". This is a joke on the rules of traveling in basketball, where players are allowed to hold the ball without dribbling for two steps before they have to pass or shoot. There's a new rule that allows for readjust that doesn't count as a step, which makes counting the number of steps difficult. It's largely left up to the referee to call. Here too it seems somewhat arbitrary, between adjusting altitude to avoid hitting the ground versus adjusting altitude to steer.

## Transcript

[Beret Guy, holding a basketball and a helium balloon, is talking to Cueball. There is a basketball hoop at the right of the panel.]
Beret Guy: Check out my global atmospheric circulation trick shot!
[Beret Guy continues to hold the basketball as he and his balloon rise from the ground and Cueball looks at him.]
[Beret Guy holding the balloon rises higher and floats toward the left as Cueball continues to look at him.]
[Cueball is alone. The basketball hoop is again shown at the right of the panel.]
[Cueball is alone. The basketball hoop is again shown at the right of the panel.]
Cueball [Thinks]: ???
[Cueball walks off toward the left of the panel, with the basketball hoop at the right of the panel.]
[Nobody is present. The basketball hoop is at the right of the panel.]
[The basketball hoop is at the right of the panel. Beret Guy, seen from a distance in the background with his balloon, floats toward the right.]
[Nobody is present. The basketball hoop is at the right of the panel.]
[Again, nobody is present. The basketball hoop is at the right of the panel.]
[The basketball hoop is at the right of the panel. Beret Guy, seen from a distance even further in the background and higher, floats toward the left with his balloon.]
[Again, nobody is present. The basketball hoop is at the right of the panel.]
[The basketball hoop is at the right of the panel. A caption says:]
1500 years later...
[The basketball hoop is at the right of the panel. Beret Guy, still holding his balloon and basketball, floats toward the right.]
[Beret Guy, still floating, throws the basketball downwards toward the basketball hoop.]
[The ball drops through the net as Beret Guy remains floating, now to the right of the hoop.]
SWISH

# Discussion

Is "altitude control" a reference to basketball, or is the only basketball reference in the title text "travelling"? R128 (talk) 20:38, 21 July 2023 (UTC)

I couldn't say regarding Altitude control re basketball, I think it's a ballooning thing. Also, I'm pretty sure that Beret guy is using this property: https://mathworld.wolfram.com/RandomWalk2-Dimensional.html Beret guy is generally used in hyper-realistic situations, in this case, living 1500 years and being lifted by a party balloon. 172.70.110.152 22:22, 21 July 2023 (UTC)

I'm remembering that Brownian motion is common in fluids. It's not intuitive when one thinks of flow currents, to think of a random walk, in my opinion. 172.70.114.30 00:16, 22 July 2023 (UTC)

Given Beret Guy's special abilities, I think he could survive that long just fine. Trogdor147 (talk) 23:24, 21 July 2023 (UTC)

I imagine him having extended his life with AI somehow, maybe by asking so politely and persistently. 172.70.114.30 00:16, 22 July 2023 (UTC)

It's got to be something to do with the Poincare recurrence theorem. -- Iwyxc (talk) 05:44, 22 July 2023 (please sign your comments with ~~~~)

Balloons of that size only have a few grams of lift, so being able to fly with one is a remarkable power, too! --Itub (talk) 12:00, 22 July 2023 (UTC)

Even with a hypothetical vacuum balloon (which is a theoretical ideal), the lift is equal to the mass of displaced air; this implies that Beret Guy is either very light or the balloon violates the laws of physics. ~ Megan she/her talk/contribs 02:43, 23 July 2023 (UTC)
I think Beret Guy makes use of physical laws that relate to something like human art or dreams rather than conventional mechanics. Maybe Beret Guy vs Black Hat could be an unending spinoff ;} 172.70.230.19 20:37, 24 July 2023 (UTC)

In the eighth frame he appears to have shifted the ball from one hand to the other, and later back again. That is itself an additional degree of difficulty for the trick shot. 162.158.2.5 (talk) 22:43, 22 July 2023 (please sign your comments with ~~~~)

I see it just as having twisted the other way. Same hands, 180° in vertical axis. Though could also be 180° in a fourth(+) spacial dimension, as much as one of the three that even xkcd characters mostly actually live in... Beret Guy's powers would easily cover that, too. 172.70.162.101 04:21, 23 July 2023 (UTC)

--- I removed factually incorrect statement: "Perhaps this strip's inspiration was that a 3-dimensional discrete random walk has a finite expected number of steps to return to the origin.". The expected number of steps to return is infinite even in dimension 1 : https://math.stackexchange.com/questions/306467/expected-number-of-steps-for-reaching-k-in-a-random-walk

For a discrete random walk over a FINITE set of states (as would result if we say mesh the planet 2D surface by dividing it into a finite number of 1m x 1m squares), then of course there is a finite number of expected steps to return, which using symmetry can be calculated to be N steps if there are N states in total (i.e., over very long times, we need to spend about the same time on each state, something that any value other than N would fail to meet tending to infinity). 172.70.54.223 (talk) 22:58, 22 July 2023 (please sign your comments with ~~~~)

Note that BG does not return to the starting point. Same issue of indeterminate (possibly infinite) travel-time to a specific-enough point, following the path dictated by the 'random'-but-determinate path (each visited position at each successive time has a successor position clearly mapped out from it, creating a weaving path that never crosses in spacetime but may or may not visit the intended destination/region in space at multiple timestamps), but then this is SG. And he has an 'understanding' of the physical world that exceeds ours so might only start his trick-shot at the moment when he knows the 'conveyor' he's catching onto (with or without the ability to choose to cross altitudes, and thus change conveyors, as per title text) will definitely accomplish his aim within an acceptable(!) time-frame... 172.70.162.101 04:21, 23 July 2023 (UTC)
So how did Randal come up with 1500 years? This seems much too fast: earth has an area of about 5e14 m2. If winds average 5 m/s (which seems high) then it would take 1e14 s = 3 million years to return given your "N steps" long term expectation. And this is assuming a 2D case; it's unlikely he could make a basket from 20 km up, so the states should actually be much higher than 5e14. Shortening to 1500 years would require a non-uniform distribution of states where it's more likely he'll return to the starting point. Maybe there are circular currents that tend to bring air back to the starting place that Randall is referencing? Or maybe he just made up a long time without doing the calculation? Quantum7 (talk) 12:23, 25 July 2023 (UTC)

Is ExplainXKCD getting vandalized by a bunch of random people? Step93 (talk) 02:09, 24 July 2023 (UTC)

The vandalism goes FAR back, I keep an XKCD tab, I went back like 15 comics, same thing. What even IS that? I don't even recognize what the idiot pictures ARE! He/they may be counting on it being 10pm in the Eastern time zone, it's always quiet this time of night (I have almost never had an edit conflict). Someone higher up needs to block them, lock editing, something. I notice this comic was restored and re-vandalized a few times now, these morons are doing this NOW. Just restored it again, I'm sure it's revandalized by the time I submit this. I wish they could face serious enough consequences to learn they shouldn't mess around like that. NiceGuy1 (talk) 02:28, 24 July 2023 (UTC)

I find the "1500 years" thing strange. I would think that atmospheric circulation would be faster. For instance, recently the smoke from the Canada wildfires crossed the Atlantic and reached Portugal (2023-06-26) and I think it took only a couple of weeks. So I would expect that it would take some months. I just remembered to check how long it took in a balloon: "Bertrand Piccard and Brian Jones, 1999, first non-stop balloon circumnavigation in Breitling Orbiter 3, 19 days, 1 hour and 49 minutes, covering 42,810 kilometres (26,600 mi)." (from Wikipedia) Rps (talk) 10:29, 24 July 2023 (UTC)

That isn't circulation to pass over a single one-meter target. It would take some random-but-generally-very-long time, probably millennia, to pass within the area where Beret Guy could dunk the basketball through that hoop. (I notice we didn't comment on how the basketball hoop and its pole and net(!) have somehow survived for longer than, say, the Roman Republic. Nitpicking (talk) 12:04, 24 July 2023 (UTC)
In the ocean, I heard things tend to eventually drift to major flows and stay there; I infer this isn't true with the atmosphere? I would kind of imagine things trending to the equator or poles or something. 172.70.230.19 20:42, 24 July 2023 (UTC)
The water circulates at the surface and below it, rising up and sinking down in various areas (perhaps seasonal/weather-driven, but also long-lasting/near-permanent) to represent an intertwined 3d-conveyor loop every bit as much as the atmosphere does.
But anything that floats (which is pretty much anything that doesn't just sink to seafloor - at least eventually) will happily drift along to a gyre and then be left circulating that as the water that pushes it there moves downwards and onward eventually to rise back up again to 'fetch' even more flotsam and jetsom. Wind-blown (but heavier than air) stuff can also pile up, but anything as free-floating as BG and his He-balloon is going to (mostly) follow the complex system of airflow that wends its (fluctuating) way all around the planet. 172.70.90.231 21:37, 24 July 2023 (UTC)

The "Albuquerque Box Effect" makes me laugh- been to the Balloon Fiesta a few times and I've never seen them land anywhere near the launching field. Balloons land randomly all over town anywhere there is a flat spot, it's kinda great but definitely not a loop. 172.70.126.40 13:49, 24 July 2023 (UTC)

Whoever had provided the captions of the image had used "northerly" and "southerly" exactly opposite to the way the image's own labels had them. I put them into agreement, although as (for example) northerly has meanings of both going towards North and coming from the North (the latter usually w.r.t. wind, and I couldn't find a consistent and authoritative usage style about say "North winds, from the north, being therefore southerly in direction"), it is easy to see how confusion can arise. Maybe a rewrite (perhaps even a redrawing/relabelling of the diagram, at source) would be useful, with "north-heading wind"/etc disambiguating the autoantonymic language... 172.70.90.80 19:34, 24 July 2023 (UTC)

Do you think the comic could have been better if the passage of time was made more clear by there been shrubs and scenery everywhere around the basketball hoop, possibly the hoop itself crumbling and falling? 172.70.42.207 19:39, 24 July 2023 (UTC)

A subtle change. We'd have to ask Beret Guy. 172.70.230.18 20:51, 24 July 2023 (UTC)
It's Beret Guy's world, and we're living in it. Maybe he doesn't like to think about the passage of time. Andrewtheexplainer (talk) 18:08, 26 July 2023 (UTC)

Somebody with a lot of patience and persistence kept reverting overt vandalism in the history. One of the edit comments reverting the vandalism over and over again was in the theme of the comic, "i don't have the time for this, you will literally die in the next 80 years". 172.70.230.18 20:51, 24 July 2023 (UTC)

Could this comic possibly be related to the last part of Bowling Ball? It talks about the bowling ball drifting around in ocean currents and doing a trick shot, similar to how Beret Guy uses atmospheric circulation to do a trick shot. AoPS is superior (talk) 16:40, 2 August 2023 (UTC)