I wonder sometimes if we aren't all aliens to planet Earth that have arrived here from some distant Galaxy via meteorite or some other explosion of Star dust ...

Panspermia (from Ancient Greek πᾶν (pan), meaning 'all', and σπέρμα (sperma), meaning 'seed') is the hypothesis that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets,planetoids, and also by spacecraft in the form of unintended contamination by microorganisms.

Panspermia is a hypothesis proposing that microscopic life forms that can survive the effects of space, such as extremophiles, become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Some organisms may travel dormant for an extended amount of time before colliding randomly with other planets or intermingling with protoplanetary disks. Under certain ideal impact circumstances (into a body of water, for example), and ideal conditions on a new planet's surfaces, it is possible that the surviving organisms could become active and begin to colonize their new environment. Panspermia is not meant to address how life began, just the method that may cause its distribution in the Universe. (Wikipedia - https://en.wikipedia.org/wiki/Panspermia )