Posted on | October 12, 2010 | No Comments
The last few weeks were rich in surprising news about the search for life outside Good Old planet Earth. Two successive releases from the United States have shaken the convictions we hold on this topic, even though we still haven’t gotten a definitive proof for extra-terrestrial life.
The first of these two news brief came directly from NASA. While studying the fluctuation in the glow emitted by a nearby star, Gliese 581 (which is about 20 light years away, pretty close on the galactic scale), researchers at this institution found variations induced by 6 different planets orbiting the star. One of these is located sufficiently close to the star to allow for the presence of liquid water and, eventually, the appearance of forms of life. Incidentally, the gravity on this planet would equal 1.1 to 1.7 times that of Earth.
If spectrographic analysis eventually confirms the presence of oxygen on this planet, we will have a definitive answer to our quest since photosynthesis is, to this day, the only known phenomenon explaining the presence of oxygen in vast quantities in the atmosphere. Otherwise we will at least know that the possibility of finding hospitable planets is real and more likely than previously expected.
The second piece of news is about the result of experiments led at the University of Arizona. The atmospheric composition of Titan, one of Saturn’s moons, was recreated in a lab and subjected to microwave radiation simulating cosmic rays. To the joy of researchers, many organic compounds were derived from the experiment, including the five nucleotides constituent of DNA and a few amino acids. Comparing these results with a sample of the satellite’s atmosphere capture by the Cassini spacecraft in 2004, it was revealed that a few other compounds found in the experiments were present on Titan as well.
These two announcements teach us that, on one hand, hospitable conditions for life as we know it could be common in the universe and that, on the other hand, the building blocks of life tend to form spontaneously in varied atmospheres. It is thus only a matter of time until we can find a planet harbouring all these elements.