ANN ARBOR — The U.S. is the richest country in the world, yet economists estimate that at least half of Americans won’t retire with enough money saved to maintain their current lifestyle. (more…)
Geologists are letting the air out of a nagging mystery about the development of animal life on Earth.
Scientists have long speculated as to why animal species didn’t flourish sooner, once sufficient oxygen covered the Earth’s surface. Animals began to prosper at the end of the Proterozoic period, about 800 million years ago — but what about the billion-year stretch before that, when most researchers think there also was plenty of oxygen? (more…)
