GENIUS BY STEPHEN HAWKING | Smartphone & Tablet Models of the Galaxies | PBS

http://to.pbs.org/1UtjdaP
GENIUS BY STEPHEN HAWKING premieres Wednesdays, May 18-June 1, 2016, 9:00-11:00 p.m. ET on PBS.

Using smartphones and tablets to measure how far apart the Milky Way is from Andromeda.