Signs of life on a global scale: Earth as a laboratory for exoplanet biosignatures

Instead of a 2D representation of the planet complete with spatial information, the best we can hope for over the next few decades is a spatially condensed version of the planet with all relevant information collapsed down to a single point of light. A representative but closer-to-home example is the image Voyager 1 took of our home planet from approximately 6 billion kilometres away (Figure 1b). The well-known astronomer and noted science communicator Carl Sagan poetically described the Earth in this image as a “mote of dust suspended in a sunbeam”. Viewing the pale blue dot from afar