It has long been supposed that the origins of life on planet Earth may have been far more alien at the outset than many have considered. Recent studies even suggest that certain proteins that could have served as the building blocks for life on our planet may have been first introduced via an extraterrestrial carrier, of sorts.
But rather than spaceships, the likely culprit would have been more likely to be space rocks. That's right, the long-held belief that meteorites carrying certain proteins, or even very simple life forms, may have arrived in ancient times still begs the question, "are we really the aliens, after all?"
Among those who have questioned whether Earth life may really be extraterrestrial, add to the list Charles Darwin, who during a correspondence published in the summer of 1881 with a colleague, supposed that an extraterrestrial origin of Earth species may have been able to account for the seeming appearance of life, and its evolution over time, despite the then wrongly-calculated age of our planet.
David Bressan discussed Darwin's letters on extraterrestrial speculation in a recent blog post for Scientific American, where he noted the following:
In August 1881 the journal “Science” published an article with a letter exchange by two amateur geologist – British Charles R. Darwin and the German Otto Hahn- discussing the possibility of extraterrestrial life. Just some years earlier Darwin had published a book “On Origin of Species” proposing that complex life forms descended slowly over time from simple ones, however as earth seemed to be too young (based on the erroneous calculations of a physicist Lord Kelvin) to explain the observed modern complexity, the origin of microorganisms in space (which existence would predate the formation of earth) could solve this apparent contradiction.
Something of a novel idea for 1881, the concept that life on Earth may have been seeded by interactions with matter from other terrestrial bodies is a common theme today, both in the realms of scientific thought, as well as that of alternative thinking. Ever since the 1960s, the popularization of "paleocontact" theories posit the notion that early life on Earth--or perhaps even early humans--were contactees amidst intelligent beings from space who, arriving here and seeking to spread the seeds of complex thought and knowledge, either shared complex principles of architecture, mathematics, science, agriculture, and the like with more primitive peoples, or literally engaged in some far-out science experiment that gave Darwin's ideas of evolution a jump-start.
Bressan goes on to note that the ensuing article in Science, regarding Darwin's communications with amateur geologist and naturalist Otto Hahn, note behavior that seems quite uncharacteristic of Darwin, specifically in relation to what Hahn had, at the time, mistaken in a meteorite fragment for being fossilized plant matter:
Strangely also in the Science article of 1881 other very Darwin-unlike behavior appears. Supposedly Darwin, observing under the microscope the rock fragments, jumped from his seat exclaiming ”Almighty God! What a wonderful discovery! Wonderful!” and stating that indeed “life [came] down!” from space.
Nonetheless, the supposition here is that Darwin held a very high regard for the possibility that maybe life on Earth had indeed been influenced, or even instigated entirely, by the appearance of stuff from the stars. Thus, in a sense, Darwin, Hahn, and perhaps a handful of others had become some of the earliest examples of "ancient alien theorists," though perhaps not quite in the same context as the term is meant to be used today.