Life in the inner galaxy would be bombarded by comets

Comets may be bombarding planets closer to the centre of the galaxy more heavily than Earth, making things tough for life

http://feeds.newscientist.com/c/749/f/10898/s/80076ca/l/0L0Snewscientist0N0Carticle0Cmg20A4273940B50A0A0Elife0Ein0Ethe0Einner0Egalaxy0Ewould0Ebe0Ebombarded0Eby0Ecomets0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fspace/story01.htm