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
The Shoemaker and the Elves (film) The Shoemaker and the Elves (film) The Shoemaker and the Elves is a 1935 Color Rhapsodies short directed by Arthur Davis. It concerns a poor shoemaker who gives a little boy shelter from a storm. A homeless waif, staggering through a roaring snow storm, wanders into a small town and no one except a poor shoemaker will give the little boy shelter from the storm. That night, the elves come in with their equipment and material, and make a new supply of shoes for the old man. In the morning, seeing what has happened, the old man tells the boy