Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-28T00:20:04.105Z Has data issue: false hasContentIssue false

Liquid water and organics in Comets: implications for exobiology

Published online by Cambridge University Press:  17 July 2009

J.T. Wickramasinghe
Affiliation:
Centre for Astrobiology, Cardiff University, 2 North Road, CF10 3DY, UK
N.C. Wickramasinghe*
Affiliation:
Centre for Astrobiology, Cardiff University, 2 North Road, CF10 3DY, UK
M.K. Wallis
Affiliation:
Centre for Astrobiology, Cardiff University, 2 North Road, CF10 3DY, UK

Abstract

Liquid water in comets, once considered impossible, now appears to be almost certain. New evidence has come from the discovery of clay minerals in comet Tempel 1, which compliments the indirect evidence in aqueous alteration of carbonaceous chondrites. Infrared spectral indication of clay is confirmed by modelling data in the 8–40 μm and 8–12 μm wavebands on the basis of mixtures of clays and organics. Radiogenic heating producing liquid water cores in freshly formed comets appears more likely on current evidence for solar system formation. A second possibility investigated here is transient melting in comets in the inner solar system, where thin crusts of asphalt-like material, formed due to solar processing and becoming hot in the daytime, can cause melting of sub-surface icy material a few centimetres deep. Supposing comets were seeded with microbes at the time of their formation from pre-solar material, there would be plenty of time for exponential amplification and evolution within the liquid interior and in the transient ponds or lakes formed as the outer layers are stripped away via sublimation.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

A'Hearn, M.F. et al. (2005). Science 310, 258.CrossRefGoogle Scholar
Brownlee, D.E. (1978). In Protostars and Planets, ed. Gehrels, T., p. 134. University of Arizona Press, Tuscon.Google Scholar
Carslaw, H.S. (1921). The Conduction of Heat. Macmillan and Co, London.Google Scholar
Diehl, R. et al. (1997). In AIP Conference Proceedings, eds Dermer, C.D. et al. , vol. 410, p. 1114. American Institute of Physics.CrossRefGoogle Scholar
Frost, R.L., Ruan, H. & Kloprogge, J.T. (2000). Int. J. Vib. Spectros. 4 (1), 112.Google Scholar
Hoover, R.B., Pikuta, E.V., Wickramasinghe, N.C., Wallis, M.K. & Sheldon, R.B. (2004). Astrobiology of Comets. In Instruments, Methods, and Missions for Astrobiology VIII (Proceedings of SPIE, 5163), pp. 191202. SPIE (www.astrobiology.cf.ac.uk/SPIE2004.pdf).CrossRefGoogle Scholar
Hoover, R.B., (2005). In Perspectives in Astrobiology, eds Hoover, R.B., Rozanov, A.Y. & Paepe, R.R., vol. 366, p. 43. IOS Press, Amsterdam.Google Scholar
Hoyle, F. & Wickramasinghe, N.C. (1979). Diseases from Space, J.M. Dent and Sons, London.Google Scholar
Hoyle, F. & Wickramasinghe, N.C. (1986). Earth Moon Planets 36, 289.Google Scholar
Hoyle, F. & Wickramasinghe, N.C. (1991). The Theory of Cosmic Grains. Kluwer Academic Press, Dordrecht.CrossRefGoogle Scholar
Jewitt, D.C., Chizmadia, L., Grimm, R. & Prialnik, D. (2007). In Protostars and Planets, eds Reipurth, V.B., Jewitt, D. & Keil, K. p. 863. University of Arizona Press, Tuscon.Google Scholar
Lisse, C.M. et al. (2005). Space Science Rev. 117, 161.CrossRefGoogle Scholar
MacPherson, G.J., Davis, A.M. & Zinner, E.K. (1995). Meteoritics 30, 365.CrossRefGoogle Scholar
McSween, H.Y.(1979). Geochim. Cosmochim. Acta 43, 1761.CrossRefGoogle Scholar
Merk, R. & Prialnik, D. (2003). Earth Moon Planets 92, 359.CrossRefGoogle Scholar
Mostefaoui, S., Lugmair, G.W., Hoppe, P. & Goresy, A. El. (2004). New Astron. Rev. 48, 155.CrossRefGoogle Scholar
Rivkina, E.M., Friedmann, E.I., McKay, C.P. & Gilichinsky, D.A. (2000). App. Environ. Microbiol. 66(8), 3230.CrossRefGoogle Scholar
Vernazza, P., Mothé-Diniz, T., Barucci, M.A., Birlan, M., Carvano, J.M., Strazzulla, G., Fulchignoni, M. & Migliorini, A. (2005). Astron. Astrophys. 436, 11131121.CrossRefGoogle Scholar
Wallis, M.K. (1980). Nature 284, 431.CrossRefGoogle Scholar
Whipple, F.L. & Stefanik, R.P. (1966). Mém. Soc. R. Sci. Liège Sér. 5, 12, 33.Google Scholar
Wickramasinghe, N.C. & Hoyle, F. (1999). Astrophys. Space Sci. 268, 379.CrossRefGoogle Scholar
Wickramasinghe, N.C., Hoyle, F. & Lloyd, D. (1996). Astrophys. Space Sci. 240, 161.CrossRefGoogle Scholar
Yabushita, S. (1993). Mon. Not. Roy. Astron. Soc. 260, 819.CrossRefGoogle Scholar
Zinner, E. (2003). Science 300, 265267.CrossRefGoogle ScholarPubMed