Difference between revisions of "613: Threesome"

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(Explanation: certainty and loneliness)
(Explanation)
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The {{w|N-Body Problem}} in physics refers to our inability to analytically solve sets of differential equations modelling gravitational attraction between more than two bodies. Simply put, to describe the movement of two bodies reacting to each others gravity pull rather straightforward and exact formulas are known (what is called a {{w|closed-form expression}}), but for three and more bodies no such exact solutions exist. In the comic, they describe a physicist's difficulty having a threesome due to his inability to find a closed-form solution.  
 
The {{w|N-Body Problem}} in physics refers to our inability to analytically solve sets of differential equations modelling gravitational attraction between more than two bodies. Simply put, to describe the movement of two bodies reacting to each others gravity pull rather straightforward and exact formulas are known (what is called a {{w|closed-form expression}}), but for three and more bodies no such exact solutions exist. In the comic, they describe a physicist's difficulty having a threesome due to his inability to find a closed-form solution.  
  
The title text suggests they should settle for a numerical solution since a closed form solution is unavailable; however, the physicist apparently refused to do so during the previous night when Megan suggested him to. A numerical solution to predict the movements of three and more bodies would be an "open" procedural solution or simulation, which works fine for some length of time, but can deviate from the exact solution due to the {{w|butterfly effect}}. This could mean that Megan would have been fine with a thresome without knowning the exact future outcomes of this encounter, while the physicist was insisting on having an exact solution and certainty. A frequent observation in random n-body encounters is that one or more bodies are ejected from the system by achieving escape velocity - and loneliness. But there can be also stable solutions. A closed-form solution would allow to know in advance how long such an arrangement would remain stable.
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The title text suggests they should settle for a numerical solution since a closed form solution is unavailable; however, the physicist apparently refused to do so during the previous night when Megan suggested him to. A numerical solution to predict the movements of three and more bodies would be an "open" procedural solution or simulation, which works fine for some length of time, but can deviate from the exact solution due to the {{w|butterfly effect}}. This could mean that Megan would have been fine with a threesome without knowing the exact future outcomes of this encounter, while the physicist was insisting on having an exact solution and certainty. A frequent observation in random n-body encounters is that one or more bodies are ejected from the system by achieving escape velocity - and loneliness. But there can be also stable solutions. A closed-form solution would allow to know in advance how long such an arrangement would remain stable.
  
 
==Transcript==
 
==Transcript==

Revision as of 17:01, 20 February 2016

Threesome
I wanted us to try finding an approximate numeric solution, but noooo.
Title text: I wanted us to try finding an approximate numeric solution, but noooo.

Explanation

The N-Body Problem in physics refers to our inability to analytically solve sets of differential equations modelling gravitational attraction between more than two bodies. Simply put, to describe the movement of two bodies reacting to each others gravity pull rather straightforward and exact formulas are known (what is called a closed-form expression), but for three and more bodies no such exact solutions exist. In the comic, they describe a physicist's difficulty having a threesome due to his inability to find a closed-form solution.

The title text suggests they should settle for a numerical solution since a closed form solution is unavailable; however, the physicist apparently refused to do so during the previous night when Megan suggested him to. A numerical solution to predict the movements of three and more bodies would be an "open" procedural solution or simulation, which works fine for some length of time, but can deviate from the exact solution due to the butterfly effect. This could mean that Megan would have been fine with a threesome without knowing the exact future outcomes of this encounter, while the physicist was insisting on having an exact solution and certainty. A frequent observation in random n-body encounters is that one or more bodies are ejected from the system by achieving escape velocity - and loneliness. But there can be also stable solutions. A closed-form solution would allow to know in advance how long such an arrangement would remain stable.

Transcript

Megan: We had a threesome last night.
Cueball: How was it?
Megan: Awkward - it was with a physicist.
Cueball: Why's that awkward?
Megan: They can't solve the three-body problem.
Cueball: Ah, yes.


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Discussion

Any specific solution to Megan, the phycisist, and the lucky third,s problem would result in chaotic motion and no apearent repetitions. Which sounds like fun, i don,t see what Megan,s problem was. 173.245.56.191 16:05, 29 August 2014 (UTC)

I don't think this really explains the comic. The three body problem wasn't explained anywhere near enough. Leafy Greens (talk) 17:21, 16 November 2014 (UTC)

Added some more explanations and interpretations.--162.158.150.140 22:47, 18 February 2016 (UTC)