Comets and the Origin of Life

The astrobiological case for our cosmic ancestry

“…UV feature at l=2175 AS imilarly, the omnipresent UV absorption feature of interstellar dust at 2175 Å is more plausibly explained on the basis of aromatic molecules in biology compared with competing inorganic models (Hoyle & Wickramasinghe 1991;Wickramasinghe et al 2009a). Figure 6 shows the l=2175 Å absorption feature associated with dust in a galaxy at a redshift of z=0.86 -some 7-9 billion light years away.…”

“…fifth century BC) its modern revival in the context of 20th century science was largely due to work of Arrhenius (1908) and of Hoyle, the present author and many collaborators (Hoyle & Wickramasinghe 1981Wainwright et al 2003;Wickramasinghe et al 2009a). The conventional view is that life originated on Earth in a 'warm little pond'.…”

“…Experiments claiming a contrary result are mostly based on the application of very high fluxes to cultures of bacteria for short timescales, and these are likely to be irrelevant to interstellar exposure conditions where exceedingly low fluxes of ionizing radiation are delivered over millions of years (Hornek et al 2002;Wickramasinghe et al 2009a). Close analogies to the interstellar situation are realized in the discovery of viable microbes in bees fossilized in amber for 40 million years (Cano & Borucki 1995), and in salt crystals for 250 million years (Vreeland et al 2000) -such microbes being subject to low background fluxes of ionizing radiation for astronomically relevant timescales.…”

Microstructure and elemental composition of the Tagish Lake meteorite and its astrobiological implications

“…In the early history of the planetary system, water in the form of liquid would be expected to persist for millions of years within cometary interiors (Hoyle & Wickramasinghe 2000;Wickramasinghe et al 2009). A total of some 10 11 comets contain 10 30 g of material, which is largely comprised of carbonaceous material (organics) mineral dust and water-ice.…”

“…Nanometric to sub-micrometre sized organic granules as well as filaments and trichomes were interpreted as putative microfossils by Hoover et al (2003). Initial criticisms that all such structures were modern contaminants appears to have been ruled out by the work of Hans Pflug (see Hoyle & Wickramasinghe 1982;Wickramasinghe et al 2009) andHoover (2009), but their biogenic origin still remains controversial. Initial criticisms that all such structures were modern contaminants appears to have been ruled out by the work of Hans Pflug (see Hoyle & Wickramasinghe 1982;Wickramasinghe et al 2009) andHoover (2009), but their biogenic origin still remains controversial.…”