The Milky Way may be home to 3,000 extraterrestrial civilizations, but the huge distances between our galactic brothers could reduce the chances of successful contact to a minimum, Discovery writes according to scientists.
Data compiled by NASA's Kepler Space Telescope and other observatories looking for planets outside the solar system indicate that Earth may be one of 40 billion potentially habitable worlds in the entire galaxy. And every year another life-friendly planet is formed, says Michael Garrett, head of the Dutch astronomical society ASTRON.
Sounds promising until you imagine the sheer size of the Milky Way, which spans over 100,000 light years in diameter. Light travels about 300,000 kilometers per second, but it still takes at least 4 years to contact the nearest Alpha Centauri system, and 100,000 years to get from one end of the galaxy to the other at the speed of light.
“On average, you would expect civilizations to be at least 1000 light-years apart in the Milky Way. This is a long distance, and communication assumes that you have to travel that distance twice, so, roughly speaking, we assume there are civilizations that have at least several thousand years to be able to talk to each other, Garrett says. "And we don't really know the time frame in which civilization remains."
The only available example - Earth - shows that life appeared as soon as the right conditions arose, but intelligent life grew up relatively late. That is, our intelligent history covers literally a couple of the last minutes of the general evolution of life on the planet. Hence the only conclusion suggests itself: signals of extraterrestrial life will be extremely rare for the Milky Way.
This does not mean that astronomers should stop searching. On the contrary, given the huge technological leaps in radio astronomy and data processing methods, when compared with those available for the search for extraterrestrial civilizations 60 years ago.
SETI is also extracting useful information from related projects, such as trying to find the source of mysterious radio bursts.
Of course, given the lack of funding, organizations like SETI, whose main goal is to find aliens, have a hard time, but the effort is worth it. The question is too important. Even people on the street want to know if we are alone in this universe.
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