New research on Native American origins takes anthropologists down memory lane

In school we learn that science proceeds logically from one experiment to the next, leaving in its wake a complete and certain body of knowledge.

But science isn’t like that. It twists and turns, careens and tumbles and gets stuck in deep, sticky mudholes. And sometimes, science backtracks.

That’s happened in cosmology recently, as observations of the universe’s accelerating expansion have forced theorists to go back and restore a notion — the cosmological constant — that Einstein abandoned by the scientific roadside eight decades ago.