Tuesday, April 25, 2006

Going Parabolic

I have the subjective impression that people have taken to describing something which suddenly and rapidly increases as "going parabolic." They didn't use to say this as much as they now do. In the past they liked to speak of things "increasing exponentially" to describe rapid growth, whether or not the growth was literally exponential.

Of course a computer scientist would consider an exponential rate of growth to be faster than a parabolic rate of growth.

Cf. also the slightly related term "going ballistic."


At 4:51 AM, April 26, 2006, Blogger Chris said...

I have never heard the phrase "going parabolic." Of course, Californians are trendsetters, so maybe it just hasn't made it out here yet.

What is it even supposed to mean? I suppose it connotes something which will go off to infinity, as opposed to being contained into a closed conic section? But then why not say it is going hyperbolic, which has even more energy? Working in your own pun would allow you to use a pretentious phrase and at the same time mock your own use of it.

At 8:49 AM, April 26, 2006, Blogger Jordan said...

I've never heard it either. But I would suggest "going Ackermann" or "going factorial" if you want to go beyond going beyond exponential.

At 12:34 PM, April 26, 2006, Blogger Richard Mason said...

I feel that I've starting seeing it a lot on the Motley Fool and in other investor-oriented writing.

I think it could come from one of two things, or a combination:
(a) "parabola" just meant to suggest an accelerating or upward-turning curve, perhaps by a writer with limited mathematical sophistication.
(b) a reference to the parabolic trajectory of a rocket. In this case the parabola is downward-pointing and the suggestion is that the subject will shoot up rapidly like a rocket but then return to earth.

At 12:39 PM, April 26, 2006, Blogger Richard Mason said...


(c) Stock traders try to fit parabolas to accelerating stock charts and therefore refer to any rapid acceleration as "parabolic"... somewhat conflating the model with the reality.


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