Remote sensing of homochirality: A proxy for the detection of extraterrestrial life

Homochirality is an exclusive feature of life on Earth. Although the very basic building blocks of life, such as sugars and amino acids, are common in the universe, they almost exclusively occur in only one enantiomeric form. It is assumed that homochirality is universal for all lives and is therefore a potentially very unambiguous biosignature. The detection of homochirality by polarization could prove to be a powerful technique complementary to other remote life-detection strategies. In this chapter, we will give a small overview of the homochirality of life as we know it and review some of the theories behind the origin of life. Thereafter, we will discuss the framework that allows comparison between different types of measurements and we will review the most important mechanisms contributing to the optical phenomena displayed by homochiral molecules. Finally, we will discuss the polarimetry and wavelength considerations for the remote sensing of homochirality and we will point out current and future instrumental possibilities and constraints.