Biophysicist of the Year, Bilby poo-sniffing skills, Moon donut

This week, Chris tells us about the work of Senior Australian of the Year, biophysicist Graham Farquhar, in understanding photosynthesis and the impact of a changing climate; Claire tells us whether bilbies have evolved to detect the presence of dogs or cats; and Stu tells us about a new theory about how the Moon may have been formed not from cheese, but from a giant space donut called a synestia.