Unravelling of a Controversy
Replication of Bacteria in a Cosmic Context
We all know that given the right conditions, which include water and nutrients, bacteria can grow exponentially. A typical doubling time for bacteria would be two to three hours. Continuing to supply nutrients, a single initial bacterium would generate some 240 offspring in four days, yielding a culture the size of a cube of sugar. Continuing for a further four days and the culture, now containing 280 bacteria, would be the size of a village pond. Another four days and the resulting 2120 bacteria would have the scale of the Pacific Ocean. Yet another four days and the 2160 bacteria would be comparable in mass to a molecular cloud like the Orion Nebula. And four days more still for a total time since the beginning of twenty days, and the bacterial mass would be that of a million galaxies. No non-biological process remotely matches this replication power of a biological cell. Once the immense quantity of organic material in the interstellar material is appreciated, a biological origin for it becomes a necessary conclusion. This was the position we had arrived at in 1980, and it continues to constitute one of the most compelling arguments in favor of cosmic biology.
But where are the astronomical locations where conditions for replication of bacteria can be found? Certainly not in the cold depths of space, where microbes could merely remain in a freeze-dried dormant state. Planets like the Earth provide too small a total mass of carbonaceous material in the right physical state to make any impact. It is therefore to comets we turned, arguing that comets are the main sources of biological particles in interstellar clouds. An individual comet is a rather insubstantial object. But our solar system possesses more than a hundred billion comets, that in total mass equal the combined masses of the outer planets Uranus and Neptune, about 1029 grams. If all the dwarf stars (sun-like stars) in our galaxy are similarly endowed with comets, then the total mass of all the comets in our galaxy, with its 1011 dwarf stars, turns out to be some 1040 grams, which is just the amount of all the interstellar organic particles that are found to be present in the dust clouds within the galaxy.
How would microorganisms be generated within comets, and then how could they get out of comets? We know as a matter of fact that comets do eject organic particles, typically at a rate of a million or more tons a day when they visit the inner, regions of the solar system. When the comets refreeze this amplified microbial material is also frozen in, only to be released when they become periodically warmed up in the inner solar system. Some of this bacterial matter may reach planets, which they can seed with life, some of it is expelled back into interstellar space.
Diseases from Space?
The next development in our story also came as a surprise and led to further clashes with orthodox science.12 June of 1977 was a particularly inclement month in Wales, and I had succumbed to one of the worst bouts of flu that I could remember. Fred Hoyle and I were in a phase of brisk telephone and fax communication at the time trying to fit a swathe of new astronomical data to our biological dust models.
All this was to change dramatically when, delirious with high fever, I telephoned Hoyle and posed the question, “Could this flu bug have possibly come from space? Could the old myth that influenza is connected with rain and drizzle be right after all? Could viruses and bacteria be carried in comet dust and actually be entering Earth to infect us at the present time?” I recalled that the connection between diseases like the common cold and influenza and inclement weather was well entrenched in Sri Lankan folklore. My mother always told us, “Don’t go out in the rain; you’ll catch the cold.”
My question to Fred brought down a pall of silence. He had listened to all that was said and replied, “I shall think about it and phone you back.” He did in fact telephone back only to agree that this could well be so! He was reminded of conversations he had many years ago with an Australian physicist E. G. (Taffy) Bowen who had pointed out that an amazing connection existed between freezing nuclei in rain clouds and meteor showers. So the evidence we needed may have already been there two decades earlier.
As a natural consequence of this line of thinking I guessed that patterns of viral diseases over the centuries may reflect the changing environment of cometary meteor showers--the Earth crossing the orbits of debris from different life-bearing comets. Could the common cold and influenza that are so common today have been absent in the portfolio of diseases in past times? I remember asking Hoyle another question. Did he know of any Shakespearean character with a common cold? Surely Shakespeare, who dealt with almost every human condition, may have thought fit to have a character sniffling with a heavy cold? After combing through Shakespeare’s plays the answer was that there were none.
This prompted us to study a variety books on medical history, including the writings of Hippocrates and Galen and the classic Indian medical treatise Charaka Samhita, all of which confirmed that there was certainly clear evidence of a changing pattern of infectious diseases over time. The twentieth-century belief that all pathogens must necessarily have a purely terrestrial origin had no basis in fact. We had argued earlier that comets carried the first life to the Earth 4.1 billion years ago, and this process of bringing new viruses and bacteria could not be assumed to have stopped at some distant time in the past. Comets are with us still and so must continue to have an effect.