British scientists say Philae’s comet could harbour microbial life; claims criticised


Two leading British astronomers have claimed that comet 67P/Churyumov-Gerasimenko, which is currently being investigated by European Space Agency (ESA) through the Rosetta mission, could be teeming with alien microbial life – a claim that was quickly refuted by skeptics.

Astrobiologist Chandra Wickramasinghe of the Buckingham Centre for Astrobiology and colleague Dr Max Wallis, from the University of Cardiff in UK, believe that 67P and other similar comets could be home to microbial life similar to the “extremophiles” that inhabit the most inhospitable regions of the Earth.

The duo said that the features of the comet, named 67P/Churyumov-Gerasimenko, such as its organic-rich black crust picked up by ESA’s Rosetta spacecraft, are most likely explained by the presence of living organisms beneath an icy surface.

The two astronomers carried out computer simulations that suggest microbes could inhabit watery regions of the comet. In their model, the micro-organisms probably require liquid water bodies to colonise the comet and could inhabit cracks in its ice and ‘snow’. Organisms containing anti-freeze salts are particularly good at adapting to these conditions and some could be active at temperatures as low as -40 degrees Celsius.

Sunlit areas of P/67 Churyumov-Gerasimenko have approached this temperature last September, when at 500 million km from the Sun and weak gas emissions were evident. As it travels to its closest point to the Sun – perihelion at 195 million km – the temperature is rising, gassing increasing and the micro-organisms should become increasingly active.

Dr Wallis said: “Rosetta has already shown that the comet is not to be seen as a deep-frozen inactive body, but supports geological processes and could be more hospitable to micro-life than our Arctic and Antarctic regions”.
Wallis and Wickramasinghe cite further evidence for life in the detection by Philae of abundant complex organic molecules on the surface of the comet and in the infrared images taken by Rosetta.

Professor Wickramasinghe commented: “If the Rosetta orbiter has found evidence of life on the comet, it would be a fitting tribute to mark the centenary of the birth of Sir Fred Hoyle, one of the undisputable pioneers of astrobiology.”

The comet has a black hydrocarbon crust overlaying ice, smooth icy “seas” and flat-bottomed craters containing lakes of re-frozen water overlain with organic debris, researchers said.

Data from the comet points to “micro-organisms being involved in the formation of the icy structures, the preponderance of aromatic hydrocarbons, and the very dark surface,” said Wickramasinghe.

However, these claims have been ridiculed by mainstream scientists with many suggesting that the study shouldn’t have made it to the science programme of this major conference, organised by the Royal Astronomical Society.

Professor Alan Fitzsimmons, of Queens University, Belfast, tweeted that organisers should not stifle ideas. But he believes the research is flawed.

“No scientist active in any of the Rosetta instrument science teams assumes the presence of living micro-organisms beneath the cometary surface crust,” Uwe Meierhenrich of Université Nice Sophia Antipolis, France, told The Guardian in an email exchange.

Planetary scientist Professor Dave Rothery of the Open University posted in a comment on Facebook, “The Guardian and the RAS disgraced themselves today with the ‘top scientists’ argue case for life on comet’ piece today. I’ve just sat through the talk behind the press release and I think it fair to say that the audience was polite but entirely unconvinced. Diatoms [a type of micro-organism] in comets, my arse!”