"Yes, we are all aliens – we share a cosmic ancestry," Prof Wickramasinghe said.
"Each time a new planetary system forms a few surviving microbes find their way into comets.
"These then multiply and seed other planets."
He added: ""We are thus part of a connected chain that extends over a large volume of the cosmos. Evidence is pointing inexorably in this direction."
"As we enter a new decade – the year 2010 – a clear pronouncement of our likely alien ancestry and of the existence of extraterrestrial life on a cosmic scale." (Read article)