|Country||North Central Province, Sri Lanka|
|Coordinates||7 52' 59.5" N; 81 9' 15.7" E |
|Fall date||Allegedly fell on 29 December 2012.|
|Found date||Not published.|
Twelve days after the Polonnaruwa meteorite was "seen falling" to Earth, Chandra Wickramasinghe published in the online fringe science Journal of Cosmology that, after studying some electron micrographs, his team discovered fossilized diatoms (microscopic phytoplankton) inside the meteorite as well as cells similar to those found in the Red rain in Kerala that fell in 2001. In addition, his team of scientists reported in a separate article that they are certain that it is a meteorite that originated from a comet and that it also contained living diatoms.
Though Wickramasinghe's extraordinary claim that these microscopic shapes constitute strong evidence for panspermia, astrobiologists have determined in the past that morphology cannot be used unambiguously as a tool for primitive life detection.
In 15 January 2013 a diatom expert, Patrick Kociolek, verified that the forms pointed out in the paper are indeed diatoms. Then he added:
"There certainly is not any sign of this being fossilized material. (...) the diversity present in the images represent a wide range of evolutionary history, such that the 'source' of the diatoms from outer space, must have gone through the same evolutionary events as here on Earth. There are no extinct taxa found, only ones we would find living today. For me it is a clear case of contamination with freshwater."—Patrick Kociolek, 
Meanwhile PZ Myers, who studies evolutionary developmental biology, questions "why a space organism would evolve to look exactly like a species that evolved in a completely different environment, and how it could have converged in all its details on such remarkable similarity to a specific Earthly species? Why, we might even suggest that it clearly looks like contamination." While ignoring the environmental influence in evolution, a proponent of the panspermia hypothesis, Brig Klyce, contends that since life on Earth and life from space are closely related, resemblance would be expected.
Wickramasinghe's research paper was not peer reviewed by experts prior to publication, and early on, there were claims that Wickramasinghe's article was not an examination of a meteorite but of some terrestrial rock. Scientists from both the Peradeniya University Geology Division and the Arthur C. Clarke Institute for Modern Technologies in Sri Lanka examined fragments of the alleged meteorite, and concluded that it is a terrestrial rock formed by lightning strikes (fulgurite). The silica and quartz bulk content confirms the terrestrial fulgurite explanation, and further discards the meteorite hypothesis, as any silica in a meteorite would be present in trace amounts. Another proposed explanation holds that the alleged meteorite did arrive from space, but is associated with the billions of tonnes of terrestrial material that asteroid impact events have previously blasted into space during the Earth's geological history.
Wickramasinghe's team remark that they are aware that a large number of unrelated stones have been submitted for analysis, and have no knowledge regarding the nature, source or origin of the stones their critics have examined, so Wickramasinghe clarifies that he is using the stones submitted by the Medical Research Institute in Sri Lanka.
In response to the criticism from other scientists, Wickramasinghe performed X-ray diffraction  and isotope analyses to verify its meteoric origin. His analysis revealed a 95% silica and 3% quartz content, and interpreted this result as a "carbonaceous meteorite of unknown type". In addition, Wickramasinghe's team remarked that the temperature at which sand must be heated by lightning to melt and form a fulgurite (1770 °C) would have vaporized and burned all carbon-rich organisms and melted and thus destroyed the delicately marked silica frustules of the diatoms, and that the oxygen isotope data confirms its meteoric origin.
Wickramasinghe's team also argues that since living diatoms require nitrogen fixation to synthetize amino acids, proteins, DNA, RNA and other life-critical biomolecules, a population of extraterrestrial cyanobacteria must have been a required component of the comet (Polonnaruwa meteorite) "ecosystem".
Following a 29 April 2013 media briefing, Professor of Geology Athula Senarathna of the University of Peradeniya who carried out a research on the alleged meteorite, said that "there could not be any truth in Prof. Chandra Wickramasinghe's claim".
See also 
- "No, Diatoms Have Not Been Found in a Meteorite". Slate.com - Astronomy. 15 January 2013. Retrieved 2013-01-16.
- Wickramasinghe, Chandra; J. Wallis, D.H. Wallis, and Anil Samaranayake (10 January 2013). "Fossil Diatoms in a New Carbonaceous Meteorite" (PDF). Journal of Cosmology 22. Retrieved 2013-01-15.
- "The Polonnaruwa meteorite: oxygen isotope, crystalline and biological composition". Journal of Cosmology 22 (2). 5 March 2013. Retrieved 2013-03-07.
- "Polonnaruwa meteorite with evidence of life from outer space described the most important find in 500 years". LankaWeb. 13 January 2013. Retrieved 2013-01-15.
- Wickramasinghe, Chandra; J. Wallis, D.H. Wallis, M.K. Wallis, S. Al-Mufti, J.T. Wickramasinghe, Anil Samaranayake and K. Wickramarathne (13 January 2013). "On the cometary origin of the Polonnaruwa meteorite" (PDF). Journal of Cosmology 21 (38). Retrieved 2013-01-16.
- N.C. Wickramasinghe, N.C.; J. Wallis, N. Miyake, Anthony Oldroyd, D.H. Wallis, Anil Samaranayake, K. Wickramarathne , Richard B. Hoover and M.K. Wallis (4 February 2013). "Authenticity of the life-bearing Polonnaruwa meteorite". Journal of Cosmology. Retrieved 2013-02-04.
- "Potential, possible, or probable predatory scholarly open-access journals". Scholarly Open Access. Retrieved 2013-04-09.
- "Meteors from outer space made definitive land fall in Aralaganwila says Professor Chandra Wickramasinghe". Hiru News. 29 April 2013. Retrieved 2013-04-30.
- "Aralaganwila stones are not meteors; says Peradeniya University.". Hiru FM News. 14 January. Retrieved 2013-01-18.
- "Morphological behavior of inorganic precipitation systems - Instruments, Methods, and Missions for Astrobiology II". SPIE Proceedings. Proc. SPIE 3755. December 30, 1999. doi:10.1117/12.375088. Retrieved 2013-01-15. "It is concluded that morphology cannot be used unambiguously as a tool for primitive life detection."
- "Detection and geochemical characterization of Earth’s earliest life". NASA Astrobiology Institute (NASA). 3 December 2008. Retrieved 2013-01-15.
- "Evidence of Archean life: Stromatolites and microfossils" (PDF). Precambrian Research 158: 141–155. 28 April 2007. Retrieved 2013-01-15.
- "Diatoms…iiiiin spaaaaaaaaaaace!". Pharyngula (blog). 16 January 2013. Retrieved 2013-01-17.
- Plait, Phil (11 March 2013). "UPDATE: No, Life Has Still Not Been Found in a Meteorite". Bad Astronomy. Retrieved 2013-03-12.
- "Jigsaw puzzle from outer space divides scientists". The Sunday Times of Sri Lanka. 20 January 2013. Retrieved 2013-01-20.
- Meteorite or meteowrong?. Department of Earth and Planetary Sciences, Washington University in St. Louis. Quote: "If you can see quartz with the naked eye, then the rock is not a meteorite."
- "Astrobiologists Find Ancient Fossils in Fireball Fragments". MIT Technology Review. 2013.03.11. Retrieved 2013.03.18.