From atoms to planets: what we know, suspect or guess about life on other worlds

What can we know about life on other worlds? Basic chemical principles tell us a surprising amount about how life might affect its environment, and hence how we might detect life on other worlds. I will discuss the example of “Super-Earths” – rocky planets with size between Earth and Neptune that have no parallel in our solar system, but seem abundant around other stars. Making minimal assumptions about what we think life is frees us from the ‘terracentricity’ of basing our hypotheses about life on Earth, but still gives useful predictions. Will life on Super-Earth be detectable? Coloured? Complex? Super-Earths could be more likely to harbour life than Earth, but it will be harder to detect. As we move to more exotic environments, predictions become harder, speculations wilder, and the chemistry more exotic. Whether Super-Earths harbour astrobiologists remains an open question.