Two centuries ago a French engineer noticed something special about light from the sun and discovered the phenomenon of polarisation of light. Now using that property of light scientists have developed a technique to spot the presence of water and other biological molecules on the many Earth-like planets. With more powerful telescopes being built, they might just be able to search for life through the twists of light.
In search of light through the twists of light – Science Oxford, 20 March 2012