Panspermia is the theory, initially postulated by the Greek philosopher Anaxagoras in the 5th century BC, that life exists throughout the Universe and is dispersed by space dust, meteoroids, asteroids, and comets. While it might seem as though it's impossible for life to originate anywhere besides Earth, a recent hypothesis argues that panspermia is an inevitable result of the universe in which we live. Panspermia is a theory in which organisms are able to travel through space and seeds, carrying life across the galaxy. While scientists have yet to determine whether or not panspermia is true, many people believe the theory could help explain how life initially originated on Earth.
Panspermia is a scientific hypothesis. According to google, it is “the theory that life on the earth originated from microorganisms or chemical precursors of life present in outer space and able to initiate life on reaching a suitable environment.”
So according to this theory, no living organism on Earth has an earthly origin. Which means we all have something “unearthly” within us, and this sounds interesting. It is said that the life on Earth emerged soon after the bombardment period, because of which there was a heavy fall of various meteors and asteroids. The previously living organisms became extinct and the new life was started with these heavenly bodies.
The hypothesis refutes Darwin’s theory of evolution which changed the way of thinking about life in the 19th century.