Exo-Terrans: Where Are The Aliens?

by Creative Commons

WHERE ARE THE ALIENS? Suppose we woke up tomorrow to learn that extraterrestrial life had been discovered. What difference would that make? Set aside the extreme scenarios of popular fiction. The truth will probably be more mundane – not massive spaceships suddenly filling the sky but, instead, microorganisms found deep inside an ice-covered Moon, a non-random radio signal from a distant star system, or the ruins of a long-dead alien civilisation. What difference might those discoveries make? We know that life has emerged once. Why should it be so momentous to learn that it has emerged twice? The reason is that finding life elsewhere would radically change our picture of the Universe. At any point in time, humans will have explored only a tiny fraction of our galaxy, let alone the whole Universe. If life has emerged only once in that small sample, then it is possible that life on Earth is unique. (We might then use anthropic reasoning to explain why we inhabit the Universe’s only inhabited where else could observers find themselves?) But suppose we discover that life has emerged twice within our tiny sample – once on Earth, then again somewhere else. It would follow that life must have emerged a vast number of times across the galaxy. The discovery of independently emerging life would thus teach us that life is ubiquitous. And that discovery could have very significant implications. (The restriction to ‘independently emerging’ life is necessary because life found on meteors, asteroids, Mars or the Moon might have the same origin as life on Earth.)

148 pages, Paperback

Published May 21, 2018