the sisters found every unrelated reason their imaginative minds could conceive to visit sola and hang around jenna like overprotective mother hens : sarah supposedly harvested 'vegetation ' to replace the crops devoured by the ravenous josephine , roberta needed to improve the calibration of the solenoid , sister novis found exploring the caves of the blue planet fascinating , sister benedict had regular meetings with the research team of antares corde , and last , but not least , sister joseph was there to `` make sure purple did n't harass the dragons with their obsessive humming '' , despite the fact that the dragons were soothed to the point of bliss by the immortals ' strange music .