Letter to the Editor of The Times
LONDON, 27 February 2017 .
Sir, The recent report of Winston Churchill’s unpublished essay News, Feb 16. 2017), in which he argues that planets outside the solar system are likely to be inhabited, came days before Nasa’s announcement of the discovery of seven Earth-like planets
39 light years away orbiting the star Trappist-l (News, Feb 23).
The two announcements have a rare consonance. If life does indeed
exist on a multiplicity of planets, it would mean either that life starts
everywhere de novo with ease or it spreads from a single unknown
starting point. In view of the continued failure of science to demonstrate that life can start spontaneously in a planetary
environment, the more likely option is the latter — one proposed and developed by the late Sir Fred Hoyle and myself over the past four decades.
Microbial life from which all other life derives is transported with
comparative ease and spreads across the galaxy like an infection.
Churchill’s conjecture would then be verified.
PROFESSOR CHANDRA WICKRAMASINGHE
Director, Buckingham Centre for Astrobiology,
University of Buckingham
About the double nature of the comet as recently discovered. It is anybody’s guess what the surface will reveal.
In spite of the uncertainties inherent in the present calculation, it is possible to interpret the surprisingly large outflow of water observed from the Comet 67P/C-G (Churyumov-Gerasimenko) on June 6, 2014, when the comet was between Jupiter and Mars, as being indicative of biology. Although microorganisms in comets are likely to be in a frozen dormant state at aphelion, a sporadic resumption of metabolism will occur near perihelion if subsurface melting can take place. Metabolism builds up subsurface gas pressures of thousands of atmospheres, which is enough to cause cracks in the surface crust releasing gas and dust. Such melting could occur due to increased solar radiation or, on occasion when impacts of smaller bodies transfer kinetic energy that can be converted to heat. Comet Hale-Bopp showed sporadic activity when it was outside the orbit of Jupiter. We can argue that this activity in Comet Hale-Bopp, as well as the new evidence from Comet Churyumov-Gerasimenko, point to the resumption of bacterial activity (8).
As we await the descent of the Philae lander onto Comet Churyumov-Gerasimenko with bated breath, there would inevitably be many surprises in store. The recent discovery that the comet has a “double” structure and is probably a contact binary may be the first of many to come. It is to be hoped that more indirect evidence of biology will be forthcoming as the ROSETTA mission draws to a conclusion this year.