Good things, like valuable parcels being delivered by the Royal Mail, often take a long time in arriving. Just this morning the Daily Telegraph reported that Sri Lankan-born scientist Chandra Wickramsinghe has claimed that all humans are in fact aliens from outer space. What the Daily Telegraph failed to point out that Wickramsinghe, along with his late mentor and colleague Fred Hoyle, has been saying the same thing for around thirty years or more. There’s nothing like up to the minute reportage!
The basis of Wickramsinghe’s claims is a phenomenon termed Panspermia, the notion life on this planet was in fact “seeded” by organic material brought to earth by passing (or in some cases impacting) comets. If you are thinking at this point that this sounds like a plot device from an episode of Star Trek: Voyager, then you are correct – the show’s writers lifted the idea from Hoyle & Wickramsinghe’s work.
Note however that the theory of Panspermia does not by itself, contrary to the Telegraph’s headline writers, suggest that we are in fact aliens, or that alien life does exist elsewhere in the universe – merely that the seeds of life may come from outer space. However there is at least one theory by Francis Crick (he of DNA fame) that Panspermia might in fact be “directed” – i.e. brought either deliberately or inadvertantly by our extraterrestrial brethren. Apparently the rationale for directed Panspermia is that the probability of such life-seeds hitting earth by mere chance is literally astronomic.
See also: The Cardiff Centre for Astrobiology.