ARE WE IN A CHAOTIC UNIVERSE?

Do we finally have a handle on chaos theory and how it influences the world around us?

- Colin Stuart

When it comes to surviving in space, the tiniest things can be the difference between life and death. As Canadian astronaut Chris Hadfield said: "An astronaut who doesn't sweat the small stuff is a dead astronaut." That may be the case for human space travel, but astronomers are increasingly suspecting that the same mantra also applies to the wider universe. When it comes to the cosmos, it seems chaos theory is king.

Chaos theory traces its origins back to the 19th century. French polymath Henri Poincaré was attempting to win a prize of 2,500 crowns - a third of a professor's yearly salary - offered up by King Oscar II of Sweden and Norway to celebrate his 60th birthday. To win you had to predict the orbits of the planets. Isaac Newton's work on gravity allows you to foretell the future positions of two gravitationally intertwined objects with clockwork precision. Yet throw a third object into the mix and that ability vanishes. Poincaré failed to solve this 'three-body problem, but was awarded the prize nonetheless for important insights into why it's such a thorny conundrum to crack.

Russian mathematician Sofya Kovalevskaya also carried out important work on the problem. The puzzle is difficult because even the smallest changes in a system with many moving parts can lead to huge differences later down the line. That, in a nutshell, is the essence of chaos theory. "We wouldn't have chaos theory if we didn't study planetary orbits," says Dr Paul Sutter of the Flatiron Institute in New York.