Complex Animals Led to More Oxygen, Says Maverick Theory
For decades, researchers have assumed that higher oxygen levels led to the sudden diversification of animal life 540 million years ago. But one iconoclast argues the opposite: that new animal behaviors raised oxygen levels and remade the environment.
By Jordana Cepelewicz
How Einstein Lost His Bearings, and With Them, General Relativity
By 1913, Albert Einstein had nearly completed general relativity. But a simple mistake set him on a tortured, two-year reconsideration of his theory. Today, mathematicians still grapple with the issues he confronted.