We get so many fantastic questions sent in to Moment of Um, but today’s is a real sight for sore eyes! One listener wrote in asking what is the farthest distance a human can see, and we asked Sue Keirstead from the University of Minnesota to help us search for the answer.

Got a question whose answer is hard to envision? Send it to us at BrainsOn.org/contact, and eye personally will help you find the answer!