Seeker

by Douglas E. Richards

2016 article in Popular Science, entitled “Earth May Be Unique In The Universe: what does that mean for the search for alien life?” EXCERPT: After completing a census of the cosmos, a research team based in Sweden thinks that Earth may be more special than we thought. Scientific American’s Shannon Hall explains: Astronomer Erik Zackrisson from Uppsala University and his colleagues created a cosmic compendium of all the terrestrial exoplanets likely to exist throughout the observable universe, based on the rocky worlds astronomers have found so far. In a powerful computer simulation, they first created their own mini universe containing models of the earliest galaxies. Then they unleashed the laws of physics—as close as scientists understand them—that describe how galaxies grow, how stars evolve, and how planets come to be. Finally, they fast-forwarded through 13.8 billion years of cosmic history. What they concluded was that Earth may be unique among the universe’s estimated 700 million trillion rocky planets.