Why are Stars Star-Shaped?

Thanks to our Subbable subscriber SlugBooks.com - head over to http://www.slugbooks.com to find cheaper textbooks for college or university. And go to http://www.subbable.com/minutephysics if you want to support MinutePhysics on Subbable! And also to our Subbable subscriber Mathias Larssen! Paper on diffraction through the lens of the human eye: http://goo.gl/XEdMVd "Shape of stars and optical quality of the human eye" by Rafael Navarro and M. Angeles Losada, Vol. 14, No. 2/February 1997/J. Opt. Soc. Am. A Eye Photos courtesy of: Anthony Kelly Elliot Bennett flickr user jyotsna210 flickr user martinak15 wikimedia user Hminden Magdalena Roeseler Michael Gäbler wikimedia user Woodwalker Steve Jurvetson MinutePhysics is on Google+ - http://bit.ly/qzEwc6 And facebook - http://facebook.com/minutephysics And twitter - @minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Music by Nathaniel Schroeder http://www.soundcloud.com/drschroeder Created by Henry Reich