NPR's Skunk Bear: How Old Is Earth in Football Yards?

In this video, NPR’s Skunk Bear used a geologist’s idea to measure Earth’s history in football yards. If every inch of the field is 1.3 million years, near which yard line did humans arrive?

Skunk Bear is NPR’s science tumblr, which answers audience’s science questions through videos and animation. Watch more Skunk Bear videos here.