What do Lance Armstrong and geese have in common?

— 4:59 PM on October 26, 2006

And better yet, what do Lance Armstrong and geese have to do with the concept of Nodal Dynamics?

It turns out that the peloton (the main group of cyclists) in a bicycle race such as the Tour de France takes on an inverted V shape similar to the V shape of geese flying through the air in their longitudinal sojourns.

But why? Why do these events take on a V shape? Is it to improve aerodynamics? That would be my first guess. Although I should point out that I don't really care whether the shape is an inverted V or an S. What's interesting to me is that a group of individuals would end up in some kind of organized formation without planning it or thinking about it.

For example, I don't think the head goose said, "Okay guys, this is gonna be a long flight. Line up in V formation behind me." And while certain cyclists might like to instruct all other riders to remain behind them in a V formation, I doubt they would for long. Indeed the leaders of these formations change frequently which make the underlying dynamic even more interesting.

Okay, back to why. The latest studies on geese (http://www.loc.gov/rr/scitech/mysteries/geese.html) suggest they fly in a V to conserve energy and to keep track of other geese in the group.

They might benefit just as much aerodynamically from flying in a straight line, each successive goose being slightly higher than the one in front of it. However, it's not hard to think of reasons a goose might prefer being slightly offset to the left or right. For example, what if the lead goose makes a sudden stop... terrible pile-up in the sky. The geese apparently want to maintain a visual buffer to help them avoid collisions and keep track of the others.

These same principles apply to cyclists who can save significant energy by drafting off one another. There may be an additional dynamic at work with cyclists though. In order to maintain good positioning, they often want to be on the outside of the peloton. Where the roads permit, this leads to the inverted V shape as riders vie for the outside position. (http://forum.wolframscience.com/archive/topic/230-1.html)

Neither goose nor cyclist sets out to maintain a V shape, instead each individual obeys a set of basic rules which give rise to the larger structure.


  • Expend as little energy as possible by drafting.
  • Position myself where I have a clear visual line of sight.
  • Avoid flying too closely to another goose.


  • Expend as little energy as possible by drafting.
  • Position myself where I have a decent visual line of sight.
  • Avoid riding too closely to another cyclist.
  • Position myself where I have the best opportunity to attack or to challenge an attack if other riders try to jump ahead.

I'm sure computer simulations have been performed on both of these scenarios using similar sets of basic rules. If anyone knows of some good examples, please post a URL.

Similar concepts are at work when we consider multi-core processors, graphics cards or nodes on the web with sets of identical components performing similar tasks. Could it one day be possible to simply tell a chip how to behave, throw it in with a bunch of others, and expect complex organization and structure to emerge naturally? We can do this now to a limited extent, but the resulting behavior is usually more interesting than useful.

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