Do we live in a "galactic ecosystem"? Once we evolve into a true space-faring, interstellar race, will we bump into other alien species competing for the bounty of our galaxy's resources?
Could such a competition define mankind as a Milky Way heavyweight? Or due to our willingness to "reach out" to extraterrestrials, might we get exterminated/assimilated/eaten faster than we can say "You were right, Stephen Hawking!"?
Should we just stay quiet, in case our ET neighbors don't like us?
This scenario is being pondered by Adrian Kent of the Perimeter Institute in Waterloo, Ontario, Canada, in a paper on the arXiv titled, suitably, "Too Damned Quiet?"
Why we haven't discovered an extraterrestrial civilization, despite decades of listening out for a telltale signal, is known as the "Fermi Paradox." If advanced extraterrestrial civilizations are out there, why haven't they made themselves known by now?
Kent think he knows why: Perhaps only the wiliest of alien species survive the interstellar version of evolution. Survival of the fittest, in this context, means that to make it in the Milky Way of hard knocks, you need to keep your head low.