If you don't know the story behind this comic strip, you can check out any of these sites:

http://www.huffingtonpost.com/2009/08/26/suicidal-planet-seems-on-_n_269623.html

http://www.skyandtelescope.com/news/55066637.html

http://www.latimes.com/news/nationworld/nation/la-sci-planet27-2009aug27,0,5882308.story