Gas clouds can get violentRex/ShutterstockBy Mark ZastrowRocky Balboa would be proud. Halfway across the Milky Way, a gas cloud has punched a hole in the galaxy, leaving a blast wave and a gaping void 3000 light years across. Compared with our galaxy, this cloud, named CHVC040, is a lightweight: only 16,000 times the mass of the sun. It is moving at...