New approach in search for alien life - Australian Broadcasting Corporation
Scientists are recalibrating their search for alien life to take into account the possibility that radically different life forms may exist in environments which would be extremely hostile to organisms such as those found on Earth.
A new two-pronged approach designed by researchers from NASA, the SETI Institute and several universities, attempts to replace Earthling-biased preconceptions of what constitute conditions for life.
The paper, to be published in the December issue of the journal Astrobiology, proposes a new system for classifying exoplanets (those outside our solar system) using two different indices.
An Earth Similarity Index would categorise a planet based on how similar it is to Earth, including its mass, radius and temperature. Under this index, the distant ‘Goldilocks’ world of Gliese 581g comes close to Earth.
Meanwhile, the Planetary Habitability Index would look at issues such as the presence of a stable substrate, available energy, appropriate chemistry, and the potential for holding a liquid solvent.
The recipe is designed to minimise the biased search for “life as we know it” and to take into account life that might exist under more exotic conditions, study author astrobiologist Dr Dirk Schulze-Makuch from Washington State University said.
For example, scientists speculate that hydrocarbon lakes on Saturn’s moon Titan could host a different form of life, after studies of hydrocarbon environments on Earth found them habitable in principle.