The circadian system in animals, humans and plants is fundamentally important because we are living organisms surviving on a planet with a 24-hour day and night cycle. It helps us to remain in synchrony with external environmental time, so we know when to be awake or asleep, active or rest. The circadian system is reset on a daily basis through exposure to light ("zeitgebers"), especially the sun.

This photo is of Dr. Tami Martino's hand reaching out to the sun. Her research program is focussed on understanding how light and circadian biology can help us to live longer and healthier lives.