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Rare Earth Index

earth Is Our Planet So Special?
Could we be alone in our part of the galaxy, or more dramatic still, could we be the only technological society in the universe? Rare Earth, a book by Peter Ward and Donald Brownlee (University of Washington) point out the many ways in which our solar system may be optimized for our existence.
fermi Paradox Fermi Paradox Part 1:
Our Galaxy Should Be Teeming With Civilizations, But Where Are They?
Is there obvious proof that we could be alone in the Galaxy? Enrico Fermi thought so -- and he was a pretty smart guy. Might he have been right?
fermi Paradox Fermi Paradox Part 2:
What's Blocking Galactic Civilization?
Could galactic empires exist? In a previous article, we noted that there has been plenty of time for aliens keen on colonizing the Milky Way to pull it off. Why does the cosmos look so untouched and unconquered? What is keeping advanced extraterrestrials from claiming every star system in sight?
fermi Paradox Fermi Paradox Part 3:
Zookeepers, Alien Visitors, Or Simple Life; How Can We Explain Our Isolation?
Its possible that the aliens have done cost-benefit analyses that show interstellar travel to be too costly or too dangerous to warrant ambitious colonization efforts. An alternative suggestion that would explain our apparent solitude is that the Galaxy is urbanized, and were in a dullsville suburb.