A mechanism for interstellar panspermia

W. M. NapierAffiliated to Centre for Astrobiology, Cardiff University.††E-mail: wmn@star.arm.ac.ukArmagh Observatory, College Hill, Armagh BT61 9DG

Affiliated to Centre for Astrobiology, Cardiff University.

†E-mail: wmn@star.arm.ac.uk

ABSTRACT

Metre-sized boulders ejected from the Earth by large impacts are destroyed through collisions and erosion by impacting zodiacal cloud dust particles. The time-scale for such disintegration in a dense zodiacal cloud may be 104 yr. Once reduced to a critical size, the particles are rapidly ejected from the Solar system by radiation pressure. The critical size for ejection is of the order of a micron, large enough to protect groups of micro-organisms within them from solar ultraviolet irradiation. Such life-bearing particles are ejected at a mean rate of 1020 per million years. During passages of the Solar system through or close to dense molecular clouds, a significant proportion of the particles may be incorporated into protoplanetary systems and protected from cosmic rays within growing planetesimals. The specific number density of micro-organisms so deposited is highest in small, dense molecular clouds. On the assumption that this ejection mechanism is common in other planetary systems environmentally capable of supporting life, a 'chain reaction' may seed the disc of the Galaxy within a few billion years. In that case it is unlikely that life originated on Earth.

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W. J. Baggaley. (2006) Interstellar dust in the solar system. Earth Moon and Planets 95:1-4, 197
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http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2966.2004.07287.x?journalCode=mnr