We have read Tim Palmer’s article “The real butterfly effect and maggoty apples” (Physics Today, May 2024, page 30) with much interest. He writes that the popular conception of the butterfly effect, in which “the flap of a butterfly’s wings in Brazil can set off a tornado in Texas a week later,” is “folklore” that “isn’t quite correct.”
We recently published a relevant paper on this topic.1 We conclude that a butterfly in Brazil cannot cause a tornado in Texas because of its tiny spatial scale and the dominant role of molecular dissipation at that scale.
The notion of a butterfly’s flap causing a tornado is distinct from that of a sensitive dependence on initial conditions affecting the solutions to the equations of motion. Our paper offers a scientific discourse that the former effect is not at all plausible for the real atmosphere. In our chaos studies,2 we have focused on finite predictability in Edward Lorenz’s models of 1963 and 19693 and on three kinds of butterfly effects within those models.
We offer more comments at the online version of Palmer’s article.
