When I started grad school, one of the things my thesis adviser suggested I do was to spend a few hours looking at the Palomar Sky Survey plates (this was in 19

When I started grad school, one of the things my thesis adviser suggested I do was to spend a few hours looking at the Palomar Sky Survey plates (this was in 1980). I spent many pleasant hours doing that, and what was striking was how few perfectly symmetric spiral galaxies there are, in relative terms. You see beautiful symmetric galaxies pictured in your Astronomy text books, but in truth most spirals are warped, or show distortion from a nearby companion, or obviously are merging with another galaxy, etc. Most spiral galaxies are deformed.