NEW YORK —

It's a big year for throwing. The greatest closer in baseball history, Mariano Rivera of the Yankees, is retiring. Aroldis Chapman, the overpowering Cincinnati Reds reliever, continues to fire fastballs beyond 100 mph.

And now some scientists say they've figured out when our human ancestors first started throwing with accuracy and fire power, as only people can: Nearly 2 million years ago.

That's what researchers conclude in a study released Wednesday by the journal Nature. There's plenty of skepticism about their conclusion. But the new paper contends that this throwing ability probably helped our ancient ancestor Homo erectus hunt, allowing him to toss weapons — probably rocks and sharpened wooden spears....