400-Year-Old Math Problem Solved. Could Make Stacking Oranges Much Easier.

If they're not using crates to contain fruit, grocers face a dilemma of how to stack round produce without the goods ending up in a tumbled mess all over the floor. Now, that a 400-year-old math problem has finally been solved, they have their official answer.

Four centuries ago, a mathematician suggested that the best way to stack round objects was in a pyramid. Now, the work of modern mathematicians and a computer program has proven that this idea is in fact the best possible way. (Photo credit: Shutterstock)

According to New Scientist, Johannes Kepler said a pyramid arrangement was likely the most stable way to stack bunch of round objects. While this practice might have been adopted since the German mathematician posited the idea in 1611, perhaps even before, he could not prove it mathematically.

Fast-forward to the 21st century. University of Pittsburgh mathematician Thomas Hales published a proof of Kepler's idea, something he first presented in 1998, but the 12 people who reviewed the 300-page work said they could only be "99 percent certain" Hales' proof was correct, New Scientist reported.

Anticipating such a problem, Hales started working on a computer program that could verify it in 2003. Now, 10 years after beginning that project, Hales and his team have their answer: They proved Kepler's idea.

"An enormous burden has been lifted from my shoulders," Hales told New Scientist. "I suddenly feel 10 years younger!

"This technology cuts the mathematical referees out of the verification process," he continued. "Their opinion about the correctness of the proof no longer matters."

Alan Bundy with the University of Edinburgh in the U.K., who was not involved with this proof, told New Scientist that he hopes the work of Hales and his colleagues encourages other mathematicians to use proof assistants.

"A world-famous mathematician has turned his hand toward automated theorem proving, that kind of sociological fact is very important," Bundy said.