The idea is simple. Life from space seeded the barren Earth, which brought us our original genetic programming. It does not though answer the question of how life arose in the first place; it just moves it from Earth to another location. As attractive and rich in implications as the idea is, the mechanism by which genetic material might make the trip is a puzzle. How do we come up with a plausible explanation for transporting a life bearing rock sample from a planet in another solar system to Earth? A supernova is an unsatisfactory explanation for ejecting this material from one stellar system to another. Any star massive enough to go supernova has too short a life span to develop life. Furthermore, the energy of the ejection process would sterilize any life if it existed. A meteor impact could eject rocks bearing primitive life forms from a distant planet into space. By a gravitational slingshot effect, another passing planet could kick this material into the Oort Cloud of that star. From there our Sun passing within a light year could exchange vast numbers of objects such as comet cores, asteroids, and meteors with the original system. If the original rock becomes one of the exchanged objects, then the blueprint for life becomes associated with the Sun. Any event perturbing the orbit of this rock sends it in into the inner solar system. This gives the life bearing rock a chance to run into a new and possibly hospitable home--Earth. The hypothesis requires a series of chance encounters. However, if you play the numbers enough then even the long shots come up sevens.
