Where did we come from? The radical answer proposed by Fred Hoyle and I in the late 1970s was that we came from space. Our genes and those of all living forms on Earth were brought here by comets, neatly packaged within cosmic microorganisms. The idea was the result of careful analysis of astronomical and biological data over several years.
This theory flew in the face of a long-held paradigm of an organic soup on Earth from which life arose. And the marriage of biology and astronomy was fraught with difficulties. Life was considered the prerogative of biologists, the universe of stars and galaxies that of astronomers.
But for us, the facts led the way. The information content of life even in its simplest form had to be reckoned on a superastronomical scale. So we argued that the molecular arrangements bearing this information could not arise under the hopelessly diminutive conditions that existed in a "warm little terrestrial pond".
The origin of life must surely involve the combined resources of all the stars in all the galaxies of the universe. Once originated, the dispersal and distribution of life across cosmic distances would be assured by virtue of the well- attested resistance of bacteria to the harshest of conditions in space.
In the late 1970s there was also a growing body of evidence for biochemical substances in the interstellar clouds of deep space. Astronomical observations first made by my brother, Dayal Wickramasinghe of the Australian National University, and David Allen showed in 1979 that cosmic dust had a composition similar to dried-out bacteria. They also showed the same conclusion to hold for the dust that flowed out of Halley's comet in March 1986.
For us the discovery that clinched the theory was the realisation that one-third of all the available carbon in interstellar space had to be tied up in the form of hollow organic particles with the average size of a bacterium and with spectral properties that could not be distinguished from biological material. No other process apart from biology seemed reasonable to invoke in order to produce the vast amount (some 1030 tonnes) of bacteria-like matter that existed in our galaxy alone.
While a small Cardiff group continues to explore the new vistas that have opened, others have begun to retrace our steps of validating the life-from-space idea. A decisive experiment to show that microbial life is still arriving at the Earth from comets is being planned by the Indian Space Research Organisation in collaboration with the Cardiff group. The aim is to collect large quantities of stratospheric air using sterile equipment (cryopumps) carried aboard balloons, and to search these samples for hints of alien microbial life.
The ISRO has set aside $500,000 for the project's first stage and has asked Cardiff to contribute a nominal Pounds 15,000 by way of acknowledging the collaboration. So far the response from Cardiff has been disappointingly negative.
Our early work in this area was supported and encouraged by the late C. W. L. Bevan, former principal of University College Cardiff. Subsequent administrations at Cardiff have adopted a hostile attitude to our work for reasons unconnected with science. It has been fortunate, however, that for the most part progress of our programme of research did not require major funding, and such funds were often provided through the generosity of private benefactors.
Chandra Wickramasinghe is professor of applied mathematics and astronomy, School of Mathematics, Cardiff University.