 The general concept of such an energy-transferring shell had been advanced decades earlier by author Olaf Stapledon in his 1937 novel "Star Maker", a source Dyson credited publicly.Dyson also proposed the creation of a "Dyson tree", a genetically engineered plant capable of growing on a comet.He suggested that comets could be engineered to contain hollow spaces filled with a breathable atmosphere, thus providing self-sustaining habitats for humanity in the outer Solar System.