The Answer to Fermi's Paradox? --"Near Universal Early Extinction of Life in the Cosmos" (Friday's Most Popular)
"The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens," said Aditya Chopra at Australia National University. "Early life is fragile, so we believe it rarely evolves quickly enough to survive. Most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable. The mystery of why we haven't yet found signs of aliens may have less to do with the likelihood of the origin of life or intelligence and have more to do with the rarity of the rapid emergence of biological regulation of feedback cycles on planetary surfaces."