Thursday, 28 July 2011
Last century astrobiology from ‘instant expert’ Caleb Sharf
Astrobiology "Instant Expert" sneers at panspermia
What to make of Caleb Sharf, head of an Astrobiology Centre in New York, brought in by New Scientist as an “instant expert” (New Scientist, 7 May 2011)?
He seems 'expert' only in the search for extra-solar planets and the questionable concept of “habitable zones”. This concept assumes liquid water on the planet surface – even if applicable for 'intelligent' humanoid life, modern studies of microbe 'extremophiles' show it is far too restrictive.
Sharf dismisses as “highly controversial” studies that don't fit his preconceptions, ignoring for example the cogent answers by NASA's David McKay over the bio-signatures and microfossils in meteorite rocks from Mars. Of course, McKay's highly significant claims had to be challenged, but that doesn't equate to ignoring how they have survived the critics – and giving greater weight to Martian methane gas and Titan's hydrogen gas traces in the atmosphere.
Colin Pillinger's group found other evidence for life in a Mars meteorite; he explained in New Scientist (21 May, p.39) that the distribution of organic material within the carbonates could not be understood as contamination. Colin himself was convinced the finding was real – that it's 'controversial' gives impetus to scientific progress, but an outsider's use of this to dismiss strong evidence is contrary to scientific method.
Sharf uses “controversial” likewise to dismiss the “panspermia hypothesis”, to avoid recognising that a range of studies and supporting evidence over several decades have established panspermnia as a scientific theory. He shows his prejudices as depicting panspermia as life transport across the universe (presumably faster than light!) and attaching “if” to microbial life being tough enough for space transport.
While it was traditional last century for scientists to sneer at ideas of extra-terrestrial life, astrobiological science certainly came into the mainstream following NASA's 1995 claims, so the reversion in this 'Instant Expert' feature reflects badly on the New Scientist.