국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Voyages to Mars : Chapter 15
저자	Bergreen, Laurence
Keyword	CONTAMINATION;; EXOBIOLOGY;; EXTRATERRESTRIAL LIFE;; LIFE SCIENCES;; MARS (PLANET); MICROORGANISMS;; PROVING;; ROCKS;; SOLAR SYSTEM;; TOXICITY;; UNIVERSE
URL	http://hdl.handle.net/2060/20100025879
보고서번호	NASA/SP-2010-4704
발행년도	2010
출처	NTRS (NASA Technical Report Server)
ABSTRACT	In this relatively transparent and tumultuous era, NASA contributed to the revolution in Mars science with the 1996 announcement of the discovery of possible ancient microbial life on Mars. Today, the controversy about the evidence persists, but at the time, a Martian meteorite recovered in 1984 known as ALH84001 suggested that primitive, microbial life once existed on Mars and might still be there today, concealed beneath its parched, toxic surface, hidden deep beneath subsurface rocks. When Science magazine posted an early version of the article, titled Search for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH84001, on its Web site in July 1996, it received a million hits, one gauge of interest.6 If accurate, the article offered the first scientific evidence of life on Mars, not a theory, whim, or conspiracy. The implications, both scientific and philosophical, were immense, and even scientists, in fact especially scientists, were apt to become emotional on the subject. It might be expected that Carl Sagan endorsed the article and its implications, but an earlier comment of his- "Extraordinary claims require extraordinary evidence" -was as far as he went. The remark implied that the article s findings did not quite meet the test. Nevertheless, the possibility that some form of life, no matter how simple, had once existed gave NASA s Mars program a new impetus, focus, and newly enhanced area of research: astrobiology. The implications of life in some form on Mars held out the promise of a new paradigm concerning life throughout the universe. If it was established that life, even in the form of simple microbial activity, existed on Earth and Mars, it became plausible that life, in one form or another, primitive or advanced, was widely distributed throughout the solar system and the universe. If true, astrobiologists were in a position to pose questions as to how and where life first arose. Had it spread from Mars to Earth via meteors, or vice versa, or from a common source? At the same time, many scientists remained deeply skeptical, even hostile, to the finding of life on Mars, arguing that the meteorite was contaminated with terrestrial life, that it offered nothing more, and possibly even less, than evidence of life on Earth. What had seemed to rank as one of the seminal scientific discoveries of the era gradually lost support and credibility in the scientific community, and NASA, after endorsing the article at the highest levels, gradually moved on. Even if the ALH84001 contained Martian nanofossils, which came to appear somewhat unlikely, the discovery (if that is what it was) required confirmation, which could best be found on Mars, rather than in meteorites presumed to have originated on the Red Planet, and that evidence (while entirely plausible and consistent with what is known about Mars) has yet to be found and confirmed. As a result, the Holy Grail of NASA s Mars program remains a tantalizing possibility.