Where SETI should search for intelligent life

Despite the searing radiation created by abundant stellar explosions, the inner region of the Milky Way could be the best place to search for intelligent extraterrestrial life, scientists say. That’s because its galactic habitable zone—so-called because it hosts the right materials for life to evolve—has far more planets in its inner regions than its outer ones. Until recently, astrobiologists thought that this dense inner region of stars would suffer from a larger number of supernova explosions, baking the planets in ultraviolet radiation and stunting or eradicating life before it developed intelligence. Now, new research suggests that—given the time it could take for intelligent life to evolve—the planetary population in the interior is significant enough to outweigh that risk. The researchers, writing in this month’s issue of Astrobiology, say that technologically advanced civilizations would have had a good chance of emerging on these planets up to 2 billion years before they did on Earth, especially in areas above and below the galactic plane (where slightly fewer explosions occur). Although the study doesn't estimate how many intelligent civilizations could exist, it does suggest that the inner galaxy is where groups like the Search for Extraterrestrial Intelligence (SETI) should be aiming its telescopes.