Seeking ET's Home Address

Scientists from SETI and the NASA astrobiology Institute recently held a symposium of scientific minds to debate where planets might be found that could be home to life. For a very long time, scientists believed that class M stars (Red Dwarfs) would be a poor place to search for habitable planets. It was believed that any planets orbiting such low-mass stars would be tidally locked to their stars, meaning that the same face of the planet would always face the star. Just like our moon always points the same face toward the Earth. Further, the planet would need to orbit far nearer to the colder red dwarf star to be warm enough for liquid water to exist. This close proximity would place it very close to the star's tumultuous chromasphere. It was thought that these facts would make any planets circling Class M stars poor locations for life to take hold. Further it was thought that the low mass of these stars meant that there was very little material available during their formation from which planets could be accreted. The current consensus however seems to be on the change. We now have years of successful extrasolar searches to draw upon. Planets are now considered ubiquitous in the universe. Since class M stars are the oldest and most plentiful stars that means that there just may be some planets circling a few of them that might harbor life. It's a question of odds. Red Dwarfs burn their hydrogen fuel at an extremely miserly rate. It is thought that every red dwarf that ever formed in the universe is still happily fusing its hydrogen into helium. A Class G star like our sun is thought to last only about 10 billion years. A Class M on the other hand will last 100 billion years. So if a planet happened to form and present a life-friendly environment, it would be stable for an extremely long time allowing any life that's taken hold there a inordinately long time to evolve. That means if there are advanced civilisations out there, this is where they would be found.


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