Most of the stars discussed at this week's international astrophysics symposium at the University of Hong Kong are millions of years old, but one of them is just 86 years young, and a product of the city's education system. Clifford Matthews, a professor emeritus of the University of Illinois at Chicago, was one of 180 scientists from 20 countries attending a five-day meeting of the International Astronomical Union to discuss 'Organic Matter in Space - the Quest for Life's Origins'. The meeting, which ended yesterday, was the first held in the city since the union was formed in 1919. The IAU represents the world's top astroscientists. Professor Matthews, who gave an anecdotal speech at the symposium dinner on Thursday night and delivered a closing scientific paper - 'Hydrogen Cyanide Polymers are the Bridge Between Cosmochemistry and Biochemistry in Space' - yesterday afternoon, is a star not just for his controversial theory about how life started, but also for his long personal history with Hong Kong. Explaining his theory he said: 'Hydrogen cyanide is a very common molecule in space, and what our research has shown over the years is that, chemically, it joins to itself, polymerises and form long chains very readily. That's a key point. 'We've pointed out that these chains are all over space. They're connected with comets, meteorites and elsewhere, and on the early Earth it's believed there was a bombardment of meteorites, and especially comets, and that brought a lot of these hydrogen cyanide polymers. 'The significance of the polymers, and our research over the years has shown this to be really significant, is that when you boil them with water, you get primitive proteins, amino acids, purines and pyrimidines, nitrogen heterocycles - the compounds that form the side chains of RNA and DNA.' Professor Matthews said it was very likely that same process occurred elsewhere in the universe and that basic life was not peculiar to Earth. 'We're saying that's how life started on Earth. We can only study biochemistry on Earth, but, although this says a lot about how life may have begun on Earth, the implication is that ... it is very likely there is life elsewhere, and I am one of those who thinks there is.' But if his theory challenged his audience, his life story gripped the symposium banquet at the Repulse Bay Hotel, earning him a standing ovation. Born in 1921, Professor Matthews attended Diocesan Boys' School before going to the University of Hong Kong to specialise in science. His studies were interrupted by the war, though, and he fought against the Japanese. 'I was a member of the Hong Kong volunteers - civilians - and we were mobilised very quickly and fought alongside British, Canadian and Indian troops. My unit, the No3 machine gun company of the volunteers, happened to be in Wong Nai Chung Gap,' Professor Matthews said. 'The Japanese landed during the night of December 18, 1941, and took over Kowloon and the New Territories, and were crossing over into Hong Kong Island. We fought very hard and had a 70 per cent casualty rate, but my younger brother and I were very lucky. That very night we were sent as messengers between the pillboxes, and we were sent to tell the Canadians the Japanese had landed. Because of that we were spared. Most of our unit were killed, including three of our four officers.' He spent the rest of the battle fighting by the Wan Chai waterfront, until the Christmas Day surrender to the Japanese. Professor Matthews said the Japanese were about to enter downtown. 'There we were, with our machine guns, going to make a last stand,' he said. 'We were not going to make a move whatever happened, and I was thinking this is going to be the last day of my life. Of course that doesn't worry you in war time. 'But suddenly a British officer appeared waving a big white flag. Hong Kong had surrendered, to our great surprise.' Professor Matthews said he had no doubt that the surrender saved his life. He was taken prisoner and held in Sham Shui Po barracks before being moved to Japan for 2? years. After the war ended, he decided to continue his studies at London University's Birkbeck College, where he became interested in the origins of life. 'The most exciting thing was the presence of one the great physicists of them all, J.D. Bernal,' Professor Matthews said. 'He was Britain's most eminent scientist at the time who started X-ray crystallography. In 1947 he gave his famous Guthrie lecture on the origins of life and I was stunned at the thought that you could do chemistry to study such a subject. I kept that in mind all the time.' He went to the US after graduation, earning a PhD at Yale University, and then to the University of Illinois, where he conducted research for 30 years, eventually making the connection between hydrogen cyanide and the origin of proteins, a theory he is still developing. Professor Matthews' theory is controversial because it has a speculative element, as HKU dean of science Sun Kwok, co-chair of the IAU scientific organising committee, explained. He said he thought the theory was 'a great idea', but that he had adapted a hypothesis from chemistry and applied it to astrophysics, a discipline that required empirical evidence. 'I think it is quite likely to be true,' Professor Kwok said. 'The problem is that we can't test it. A lot of the things we are talking about at this symposium, all kinds of bio-compounds, have infrared signatures that we can detect by telescopes or other means. 'Hydrogen cyanide polymers don't have strong signatures. Even though, theoretically, they are very likely to be present or even widespread, we don't have the ability to detect them right now.' Professor Kwok said astroscientists were 'a very conservative bunch' when it came to discussions about organic material in space. This was a point stressed by IAU president Catherine Cesarsky at the beginning of the week. 'In the last few years this has become real science,' she said. 'Thirty years ago astrobiology was not considered serious because we didn't have enough knowledge. Now have important information.' Dr Cesarsky said the next step was likely to involve collecting samples from Mars 'that will tell us a lot about whether life is just on the Earth or elsewhere in the solar system'. 'We are creating more and more methodology about which questions to ask and how we can answer them,' she said, adding that there had been 'a complete revolution' in the field of recent astrobiology. Scott Sandford, a scientist at Nasa's Ames Research Centre, worked on the Stardust spacecraft mission that brought back organic material from a comet in 2006. 'We are making amazing progress in this field,' he said. 'In the last 10 years we have made more progress than in the previous century. Some of this is based on improvements in technology that simply allow us to do things we could never do before, with spacecraft and telescopes.' Dr Sandford said the issue of organics in space folded into the wider areas of astrobiology, involving questions about how life started on Earth and, possibly, elsewhere. It has broad appeal and attracts scientists from many countries and a range of disciplines, including astronomy, biology and geology. 'What we brought back wasn't life, but there was a great deal of molecular complexity,' he said. 'Both meteorites and now comet samples show that a great deal of molecular complexity was dumped on the surface of the Earth on day one. 'We have no idea how life got started, so it is hard to assess the relative importance of things being made on Earth and things being made in space and delivered to Earth. 'But one of the things I find interesting is that if you know that asteroids and comets delivered complex organics to early Earth and you know the processes that made these objects are universal, then these raw materials are going to be available every time you make a star and have a planet, so in some respects you could argue that the universality of the process ups the possibility that there is life out there.' Whether Professor Matthews' theory holds up or another explanation for the origins of life is proven, the fact is that the subject is well and truly out of the realm of religion, mythology and speculation and firmly in the domain of hard science.