The concept of life being a cosmic phenomenon is rapidly gaining support, with new evidence from space science, geology and biology. In this picture life on Earth resulted from the introduction of bacteria from comets, and the subsequent evolution of life required the continuing input of genes from comets.
Fred Hoyle was an important scientist who worked at the frontiers of astronomy and theoretical physics. In 1983 he published a well-illustrated popular book for nonscientists in which he attacked the whole idea that life originated and evolved on Earth and replaced it by 'intelligent cosmic control'.
Although Hoyle has been accused to siding with creationism – I personally disagree with this assessment. He was in favor of cosmic connection and control of origin of life on earth and elsewhere in universe and was not particularly hinting at any divine control.
In an interview, N Chandra Wickramasinghe, one of the foremost authority on the idea of life from outer space a student and collaborator of Sir Fred Hoyle – in the
frontline – mentions that two recent experiments in the United States have once again drawn the attention of scientists to the theory of panspermia.
Fred Hoyle and Chandra Wickramasinghe demonstrated correctly that interstellar clouds contain some organic molecules but their subsequent proposal for the extraterrestrial origin of life on earth and for the ability of microbes to survive in space are not substantiated by hardcore evidence. However, with the hard core evidence from other quarters coming in, this theory is gaining ground and acceptance in mainstream scientific thinking.
Panspermia - which literally means seeds everywhere, underlies the hypothesis that the (biological) stuff of life did not have its origins in terrestrial resources but in inter-stellar space.
The theory maintains that life on the earth was seeded from space and that life's evolution to higher forms depends on complex genes (including those of viruses and diseases) that the earth receives from space from time to time.)
The two experiments discussed included:
In one experiment reported in October, environmental biologists Russell H. Vreeland and William D. Rosenzweig claimed that they discovered the longest surviving (250 million years) bacterial spores locked inside a salt crystal formation in Mexico that could be revived. This was considered as evidence that life - even one-celled micro-organisms - could survive in suspended animation for eons and float on comets to far away planets
In another experiment reported, a team of scientists from the California Institute of Technology, Vanderbilt and McGill Universities discovered that small pieces of space rock could be transferred from Mars to earth without its interior get ting excessively heated up, thus enabling living organisms to ride in them
The renewed interest in panspermia also comes in the wake of space-based discoveries that include recent findings of some simple amino acids and sugars in inter-stellar space; the announcement by the National Aeronautics and Space Administration (NASA) in August 1996 of evidence of fossilized ancient life in a meteorite from Mars; evidence in the same year by geneticists that many genes are much older than what the fossil record would indicate; the discovery by a Russian microbiologist in 1998 of a micro-fossil in a meteorite was a previously unknown bacterium; and the announcement by NASA in April this year of the detection of very large organic molecules in space in its Stardust Mission launched in February and that the non-biological origins of such large molecules are not known
Early history of panspermiaUntil the late 19th century panspermia meant the passage of organisms through Earth’s own atmosphere, not an incidence from outside Earth. In this form it seems to have been used first by the Abbee Lazzaro Spallanzoni (1729-99). But almost a century before that, Francesco Redi had carried out what can be seen as a classic experiment in the subject. He had shown that maggots appear in decaying meat only when the meat is exposed to air, inferring that whatever it was that gave rise to the maggots must have travelled to the meat through the air.
A very long wait until the 1860’s then ensued, until Louis Pasteur’s3 experiments on the souring of milk and the fermentation of wine showed that similar results occurred when the air-borne agents were bacteria, replicating as bacteria but not producing a visible organism like maggots. The world then permitted Pasteur to get away with a huge generalization, and honored him greatly both at the time and in history for it. Because by then the world was anxious to be done with the old Aristotelian concept of life emerging from the mixing of warm earth and morning dew. The same old concept was to arise again in the mid-twenties of the past century, however, but with a different name. Instead of Aristotle’s warm earth and morning dew it became “a warm organic soup.”
Pasteur’s far-ranging generalization implied that each generation of every plant or animal is preceded by a generation of the same plant or animal. This view was taken up enthusiastically by others, particularly by physicists, among them John Tyndall, who lectured frequently on the London scene. The editorial columns of the newly established Nature (e.g., issue of January 27, 1870) objected with some passion to Tyndall’s Friday evening discourse at the Royal Institution on January 21, 1870. Behind the objection was the realizations that were Pasteur’s paradigm taken to be strictly true, the origin of life would need to be external to Earth. For if life had no spontaneous origin, it would be possible to follow any animal generation-by-generation back to a time before Earth existed, the origin being therefore required outside Earth.
This was put in remarkably clear terms in 1874 by the German physicist Hermann von Helmholtz4:
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It appears to me to be a fully correct scientific procedure, if all our attempts fail to cause the production of organisms from non-living matter, to raise the question whether life has ever arisen, whether it is not just as old as matter itself, and whether seeds have not been carried from one planet to another and have developed everywhere where they have fallen on fertile soil….”
In his presidential address to the 1881 meeting of the British Association, Lord Kelvin drew a remarkable picture:
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When two great masses come into collision in space, it is certain that a large part of each is melted, but it seems also quite certain that in many cases a large quantity of debris must be shot forth in all directions, much of which may have experienced no greater violence than individual pieces of rock experience in a landslip or in blasting by gunpowder. Should the time when this earth comes into collision with another body, comparable in dimensions to itself, be when it is still clothed as at present with vegetation, many great and small fragments carrying seeds of living plants and animals would undoubtedly be scattered through space. Hence, and because we all confidently believe that there are at present, and have been from time immemorial, many worlds of life besides our own, we must regard it as probable in the highest degree that there are countless seed-bearing meteoric stones moving about through space. If at the present instant no life existed upon Earth, one such stone falling upon it might, by what we blindly call natural causes, lead to its becoming covered with vegetation.”
Essentially, what Kelvin was suggesting at that time was it is possible for seeds of life to be carried between planetary or cosmic bodies. Thus almost 120 years ago the ideas that have recently come to the forefront of scientific discussion were already well known. Unfortunately there was no way at that date, 1881, whereby observation or experiment could be brought seriously to bear on Kelvin’s formulation of panspermia and the world had to wait 120 year before some sort of concrete experimental and observational proof started trickling in.
It has been known for quite some time that bacteria and other microorganism are extremely hardy. Some have been found to be living in the most unlikely places where conventional thinking would attribute life’s survival – such as in the heavy water of nuclear reactors or the highly acidic and hot volcanic areas. These extremophiles, i.e. microbes that live in conditions that would kill other creatures. It was not until the 1970's that such creatures were recognized, but the more researchers look, the more they discover that most archaea; some bacteria and a few protists can survive in the harshest and strangest of environments.
There is scarcely any set of conditions prevailing on Earth, no matter how extreme that is incapable of harboring some type of microbial life. Under space conditions, microorganisms are very easily protected against ultraviolet damage.
One may find it very difficult to believe but there is evidence that some of bacteria actually survived almost 2 years on moon’s harsh environment. What has happened was that during the sealing of a camera which was supposed to be sent to moon, somebody might have sneezed and hence left microbes inside the camera body. The camera in turn was delivered to moon’s surface to find best locations for landing. 2 years later when the Apollo astronauts retrieved this camera and brought it back to earth – this fact was discovered. Moon has almost no atmosphere and the range of temperature is very high indeed. if microbes can survive 2 years of almost vacuum and the harsh differences in temperatures, is it really far fetched to think that it would be possible for them to travel intra-stellar or interstellar distances and seed life on earth as well?
Couple this with the fact that today an impressive array of interstellar molecules has been detected and among the list are a host of hydrocarbons, polyaromatic hydrocarbons, the amino acid glycine, vinegar and the sugar glycoaldehyde14. Such organic molecules that pervade interstellar clouds make up a considerable fraction of the available galactic carbon.
Actually, theories of how interstellar organic molecules might form via non-biological processes are still in their infancy and, in terms of explaining the available facts, they leave much to be desired.
N Chandra Wickramasinghe further speculates – “
The overwhelming bulk of organic matter on Earth is indisputably derived from biology, much of it being degradation products of biology. Might not the same processes operate in the case of interstellar organic molecules? The polyaromatic hydrocarbons that are so abundant in the cosmos could have a similar origin to the organic pollutants that choke us in our major cities - products of degradation of biology, biologically generated fossil fuels in the urban case, cosmic microbiology in the interstellar clouds. The theory of cosmic panspermia that we have proposed leads us to argue that interstellar space could be a graveyard of cosmic life as well as its cradle. Only the minutest fraction (less than one part in a trillion) of the interstellar bacteria needs to retain viability, in dense shielded cloudlets of space, for panspermia to hold sway. Common sense dictates that this survival rate is unavoidable.”
So where does this leads us? Actually, to me this is a partial answer at best. While it may be indisputably established that life did not independently evolve here on earth and was in fact seeded from the stars – it still leaves us clueless about the origins of life itself, wherever it might have evolved or originated.
In this sense, we are all aliens on this planet. Something to ponder on…. I will be writing more on this topic in coming days.
