Johndale Solem origin of the shape of rubble-pile asteroids. His analytic theory of the breakup of comets by planetary tidal forces resulted in his calculation of the diameter and density of the parent comet of Shoemaker-Levy 9 as it was before breaking up in the tidal field of Jupiter in 1994 (1994a). Solem's research on interplanetary travel culminated in his MEDUSA concept, a nuclear explosive propelled spacecraft for interplanetary space travel (1994b). Gregory Matloff said this was "a surprising [propulsion] concept which might greatly reduce spacecraft mass." The concept inspired research and elaboration by the aerospace community. At the behest of NASA's
Social media and television a sign of superficiality." Interactive media such as Amazon's Alexa and Apple's Siri have enabled computers to interact with people in human-like ways. "Computers, in the way that they communicate, instruct and take turns interacting, are close enough to humans that they encourage social responses. The encouragement is necessary for such a reaction need not be much. As long as there are some behaviors that suggest a social presence, people will respond accordingly." The exponential growth in the number of social media users between 2006 and 2016 has impacted how television shows are marketed. As well, the huge increase in