Graduate School of Biosphere Science, Hiroshima University
Japan Aerospace Exploration Agency (JAXA)
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS)(JAXA)
出版者
宇宙航空研究開発機構宇宙科学研究本部
出版者（英）
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)
雑誌名
宇宙利用シンポジウム
雑誌名(英)
Space Utilization Research: Proceedings of Space Utilization Symposium
The Twenty-second Space Utilization Symposium (January 17-19, 2006: Science Council of Japan, Roppongi, Tokyo, Japan)
抄録（英）
Recent findings in planetary science have increased anticipations for extraterrestrial lives, which are also relevant to the origin of the terrestrial life. Comets and meteorites may serve as life-carrying "arks" to seed potentially habitable planets such as prebiotic Earth. Success of exogenous transfer depends on survivability of life or seed life (panspermia) encrusted in comets and meteorites. Likelihood of survival may be estimated on the basis of (i) hit rates and intensities of cosmic rays during transfer, and (ii) heat and mechanical damages caused by entry and landing impact. The latter could be evaluated by experiments and calculations, despite uncertainties such as velocity and angle of entry, presence of atmosphere/ocean, and size of a carrier, namely a panspermian ark. In contrast, influences of high-energy heavy (HZE) particles have been conceptually considered. A major concern in the consideration was the hit of high-energy but low-frequency rays that react with comet/meteorite-building materials to generate secondary or sequential radiations, or hadron shower. The energy of hadron shower radiations may be high enough to damage life in shallow interior, and could be lowered to non-lethal levels in deep interior. Thus the occurrence of internal habitable zones, or protectable bodies, depends on the frequency and energy of hit rays and the size of life carriers. This idea would be tested by simulating hadron showers with the algorithm GEANT4 and by blistering artificial "bacterial arks" with high-energy proton of >10 GeV or heavier particles of GeV levels. In the light of availability of and accessibility to such high-energy particles, the use of accelerator beam dumps is comparable and complement to space in situ experiments. Improved dosimetry for artificial hadron shower is needed to simulate natural hadron showers that panspermia would encounter during interplanetary and interstellar transmigration.
内容記述
共催: 日本学術会議
著者人数: 18人
内容記述（英）
Meeting sponsors: The Science Council of Japan, The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS)(JAXA)
隕石内ハビタブルゾーンにおける放射線・突入・衝突の影響評価に関する計画
64113107.pdf
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