Earthshine is sunlight that has been reflected from the dayside Earth onto the dark side of the Moon and back again to Earth. In recent times, there has been a renewed interest in ground-based visible and near infrared measurements of the earthshine, as a proxy for exoplanet observations. Observations of the earthshine allow us to explore and characterize the globally-integrated photometric, spectral and polarimetric features of the Earth, and to extract precise information on what are the distinctive characteristics of our planet, and life in particular. They also allow us to quantify how this features changes with time and orbital configurations.