In the sprint to identify planets beyond our Solar System, scientists scan the skies for habitable worlds similar to Earth with the goal of finding life beyond ours. With each new confirmation of smaller and more Earth-sized planets, and a possible 400 billion exoplanets in the Milky Way alone, the odds are high that habitable worlds abound. Several of the missions discussed in Dreams of Other Worlds by Chris Impey and Holly Henry have been instrumental in this research, including the beloved Hubble Space Telescope.
The book details the methods scientists use to detecting extrasolar planets, the wild variety of planets found so far, and the teams and researchers making the discoveries, including Planethunters.org, the online survey of Kepler data that citizen scientists are currently scouring for evidence of these worlds. The chapter on the Viking mission comments on how, in searching for life on Mars, James Lovelock and Lynn Margulis determined that volatile gases such as oxygen or ozone are replenished by living organisms in Earth’s biosphere and will be important biomarkers of life on exoplanets. The chapter on the Spitzer mission details the ways complex organisms on Earth developed eyes designed to best use the light of our own star, the Sun, as well as how life forms elsewhere might be adjusted to existence on a planet orbiting a red dwarf star, the most common star type in the Milky Way. While the Hipparcos mission inadvertently identified exoplanets orbiting other stars, its successor mission, Gaia, is poised to detect thousands more.
Beyond artist depictions of exoplanets in orbit of distant stars, the book considers the artwork of Chesley Bonestell whose imaginative paintings of planetary landscapes inspired his and future generations to consider the variable landscapes within our Solar System and beyond. And, of course, the gold-plated phonograph records attached to the ongoing Voyager spacecraft were intended for civilizations potentially inhabiting an exoplanet in our galactic neighborhood.
The book’s conclusion looks to the upcoming James Webb Space Telescope that will turn its infrared seeking lenses to the search of far-flung worlds. What we find, the authors remind us, is bound to completely rewrite our understanding of life and where it can exist, as well as our place in the unimaginably vast universe that surrounds us.
Read a sample chapter from Dreams of Other Worlds: http://press.princeton.edu/chapters/i10067.pdf