...is the hypothesis that life exists throughout the Universe, distributed by meteoroids, asteroids, comets, planetoids.and, perhaps most recently, by spacecrafts. It is the proposal that life forms that can survive the effects of space, such as extremophiles, become trapped in debris that is ejected into space after collisions between planets that harbor life and small Solar System bodies (SSSB).
Some organisms may travel dormant for an extended amount of time before colliding randomly with other planets or intermingling with protoplanetary disks. If met with ideal conditions on a new planet's surfaces, the organisms become active and the process of evolution begins. Panspermia is not meant to address how life began, just the method that may cause its distribution in the universe.