The gist is that self-organized molecules (ie: life) will build themselves in a single chirality (organic molecules can exist in two mirror images, chirality is the term to distinguish them; think your right and left hands). Light that reflects from organics will contain a tell-tale signature (polarization) depending on the chirality. This could be used to detect evidence of "life" on other planets. Clever.
The other day i was pondering on how complex the brain is and how superior it is to all the other organs in the body ... until i realized what organ was telling me all this.