The National Aeronautics and Space Administration's new Astrobiology Institute -- a "virtual" institute linking 11 different labs via the Internet -- has come up with its official road map for the search for life.

Laid out before a meeting of the American Association for the Advancement of Science in Anaheim, California, the map shows a convoluted course that wends its way through super-hot undersea vents, deep into the frozen Antarctic and through oceans before shooting off toward Mars and Europa, one of Jupiter's moons, and beyond.

"Now we have completed a NASA road map for astrobiology," said David Morrison, director of space at the NASA-Ames Research Center at Moffett Field, California.

"It's simply the study of life in the Universe. It is a question of what was the origin and evolution of life, is there life on other worlds, and what is the future of life on Earth and in space," Morrison told a news conference.

"The premise is that the space program has reached a point at which we can begin to answer these questions."

The Astrobiology Institute is carefully separated from the non-governmental Search for Extraterrestrial Intelligence Institute, known as SETI. NASA had launched a similar project in 1992 but less than a year later Congress put an end to what it considered expensive foolishness.

Now the new institute has secured $9 million for this year and $20 million for 2000 to try to determine under what conditions life can survive and thrive, whether these conditions do or ever did exist elsewhere in the solar system, and whether earthlings can make it out there in space.

Biologists, chemists, astronomers, physicists and a range of other specialists will team up for what NASA is billing as a unique effort to answer such weighty questions.

They will study the surprising findings that creatures can live in above-boiling temperatures in places like deep undersea sulphur vents and the thermal springs of Yellowstone Park, as well as at enormous pressures deep under the Earth's surface, and in what look like frozen wastes at the Earth's poles.

"There are environments on Earth where life does not exist, but not many," said Jonathan Trent of NASA-Ames. He is most interested in the microbes and other small creatures living in the oceans, and points out that 75 percent of the planet is covered by water.

"An unbiased exploration of the planet for life would unquestionably begin in the oceans," he said.

The possibility of oceans on Mars and Europa are what make those locations good candidates for a search for life. Mars obviously has no ocean now, but might have once, while the Galileo space mission found evidence there might be a subsurface ocean sloshing around on Europa.

"There has been an estimate that there could have been as many as five habitable planets in the solar system," David DesMarais of NASA-Ames said.

Venus might have been habitable before its runaway greenhouse effect turned it into a steamy caldron, while Chiron, an asteroid near Pluto that was recently promoted to planet status, also has the potential for a liquid ocean, DesMarais said.

Jack Farmer, an Arizona University geologist whose team will help direct future Mars missions to collect soil samples, said his group will look for "an ancient fossil record for an early period of Martian history when we think life might have been possible."

All of the scientists are clear about what they are looking for, and it is not little green men.

"Our strategy for looking for life elsewhere would be exactly like looking for life on Earth," Morrison said. He pointed out that most of the species of Earth -- in numbers and in mass -- are microbes.

"We won't bother with these strange little creatures with legs walking about on the surface. We will look for creatures that really matter -- the microbes."

Vous pouvez, vous aussi, y participer en exécutant sur votre ordinateur un programme et un écran de veille qui téléchargera et analysera les données collectées d'un radio-télescope. Il y a une faible mais captivante possibilité que votre propre ordinateur détecte un jour le faible murmure d'une civilisation située hors de notre planète Terre.

• Un tournant pour l'astronomie, attendu depuis l'Antiquité par Jean Schneider, Directeur de recherches au CNRS, Observatoire de Paris (Meudon).
• La découverte des planètes extra-solaires : qu'avons-nous appris ? Quelles perspectives ? par Michel Mayor, Astronome à l'Observatoire de Genève
• Formation et évolution des systèmes planétaires par Anne-Marie Lagrange, Chargée de recherche CNRS à l'Observatoire de Grenoble
• Images et spectres d'exo-planètes : les perspectives, par Alain Léger, Directeur de recherche CNRS à l'Institut d'Astrophysique spatiale de l'Université Paris-Sud à Orsay
• Vers la découverte d'une vie universelle ? par André Brack, Directeur de recherche CNRS au Centre de Biophysique moléculaire d'Orléans
  
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