Mumbai, Aug 31 - A young Mumbai scientist claims to have disproved a theory that living bacteria from space called 'Cometary Panspermia' could have led to the origin and spread of diseases like SARS (Severe Acute Respiratory Syndrome) that ravaged many countries in early 2000.

In his article, 'Critique on Vindication of Panspermia', 31-year-old Pushkar Ganesh Vaidya of the Indian Astrobiology Research Centre (IARC), has challenged the theory that three micro-organisms - two bacteria and one fungus - captured from around 41 km above the earth by a team comprising renowned astrophysicist Jayant Narlikar were of cometary origin.

Vaidya's paper has been published in the latest issue of the well-known, peer-reviewed Canadian scientific journal Apeiron. (Apeiron, Vol. 16, No. 3, July 2009).

The three micro-organisms were captured through special devices fitted on balloons from earth's stratosphere in January 2001 by a team of Indian and British scientists, Vaidya said, arguing that the micro-organisms exhibited 'no distinct adaptations expected to be seen in the light of the theory of evolution and the concept of niche biology.'

The experiments were conducted by a team which included Narlikar of the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, and N.Chandra Wickramasinghe of the Cardiff Centre for Astrobiology in Britain. Subsequently, the team put forward the hypothesis that such micro-organisms could not travel as high as 41 km above the Earth, so they must have come from outer space.

The experiment was repeated in March 2009 and 12 bacterial and six fungal colonies were found at similar heights. According to the hypothesis, microbial life was first brought to the earth, about four billion years ago, by comets and they continue to do so. Narlikar even contended that the dreaded SARS virus came from outer space.

However, Vaidya, who analysed the characteristics of the three micro-organisms found during the 2001 experiment, said they did not show any characteristics expected in micro-organisms which lived in comets and hence must have originated from earth only.

Vaidya said the cometary environment is an extreme ecological niche and if micro-organisms are to survive in such an extreme environment for over a million years before being deposited in earth's atmosphere in a freeze-dried state, then they must adapt accordingly as per Darwin's theory of evolution.