Here's a fun thing approximately galaxies: Sometimes they collide.
It's tough to imagine such a colossal event,a cataclysm on a scale a million trillion kilometers across. When it happens, the gravity of each galaxy grapples with the other, and distorting their shapes,drawing out tens-of-thousands-of-light-years-long streamers of gas and stars, stretching toward each others like the yearning of a lover's arms.
Source: blastr.com