theory of panspermia

COSMOS Episode 11: The Immortals (2014) examines the tenacity of life, the possibility that the seeds of life can spread from planet to planet or between solar systems, and the likelihood that we might one-day be able to communicate with an advanced form of alien life. The episode arcs through the full gamut of possibilities and limitations for life to sustain itself, spread to other worlds, and survive the dangers of deep-space travel. Neil DeGrasse Tyson describes the panspermia theory and gives a scenario wherein galaxies could be viewed as “world-making machines,” laying out the necessary foundations for life to arise as the galaxy goes through its own galactic evolution over the course of billions of years.