A new study carried out at the University of Naples has found that none of the exoplanets discovered so far have the conditions needed to form an Earth-like biosphere — the area on Earth that is home to all of the planet’s living organisms. The researchers’ analysis is based on determining the conditions necessary to kickstart oxygen-based photosynthesis — the mechanism plants on Earth use to convert light and carbon dioxide into oxygen and nutrients. If these conditions are not met, then the formation of the kind of complex biosphere found on Earth is highly unlikely. Key among these conditions is the amount of energy beamed at the planet by its parent star.