Panspermia

A well-known professor at Cardiff University, Chandra Wickramasinghe, confidently asserts that life on Earth arrived from somewhere in the cosmos around 3.8 billion years ago. The professor calls this theory ‘Panspermia’, meaning that Earth was, as it were, ‘seeded’ by some agent external to the planet itself; therefore, life on Earth is not the result of some strange internal process. According to Wickramasinghe’s theory, life may have arrived on our planet via comets; upon colliding with Earth, these comets released organic microparticles that had remained frozen – and thus well-preserved – during their journey through space.
Of course, Professor Wickramasinghe is unable to explain how life itself originated; answering this question would be like answering the age-old conundrum: ‘Which came first, the chicken or the egg?’. He does, however, argue that there is no concrete evidence to support the ‘official theory’ on the origin of life on our planet – namely, that of the mysterious ‘primordial soup’ from which life originated and evolved over billions of years.
Wickramasinghe argues that interstellar clouds – vast regions of dust and cosmic material within the Milky Way – contain a myriad of ‘interstellar seeds’ (organic microparticles) which, carried by comets or other means, represent the ‘cradle of life’. According to this theory, the Earth is nothing more than a tiny speck in a seeding process that extends (and is growing) throughout the Galaxy, although the number of planets suitable for their survival is indeed debatable.
Professor Wickramasinghe and his colleague, the late Sir Fred Hoyle, first proposed the theory of panspermia way back in 1960, sparking a great deal of controversy and excitement. Since then, the theory has never been disproved; however, there is no concrete evidence to support it either. The professor maintains that the evidence is there for all to see and will become increasingly evident over time.
If the theory of panspermia were to prove true, what would it mean for us to know that, technically speaking, we originate from space? Firstly, it would finally prove that life exists beyond our planet; in any case, we would be faced with one of the greatest discoveries of all time! Next, we must ask ourselves another question: where does this ‘interstellar’ life come from? And given the scale and vastness of the universe, it becomes difficult to answer this question – even more difficult than explaining how life on Earth came into being. But this theory suggests something else: if life has been ‘sown’ throughout the universe for a very long time, it may have taken root on planets similar to ours; so what might we find on planets where life arrived millions of years before ours?