The Search for Exoplanets
The very first planet orbiting a star other than our Sun was discovered in 1995. Within two decades of that discovery scientists concluded that such exoplanets are so common that nearly every star in the sky is orbited by at least one, although they come in a bewildering variety. In this short span of time we have learned how the lives of exoplanets and their stars are inextricably interwoven. Stars make the materials of which planets are made; they are the seeds around which planetary systems form, and they provide their planets with light and warmth. Planets can be larger than Jupiter or smaller than Earth; they can migrate through a planetary system; some may fall into their stars or may be exiled into the interstellar cold. A planet’s habitability depends on what makes the planets, and can come and go over time, as it will for Earth. How do we learn about these distant worlds? What does the exploration of other planets tell us about the history of Earth? What does all that have to do with the habitability of Earth and the possibility of finding extraterrestrial life? And what is it like on some of the billions of exoplanets in the Galaxy?
Karel Schrijver obtained his degree in astrophysics studying the magnetism of stars. His work later increasingly focused on the ever-changing atmosphere of the nearest star, our life-enabling Sun. His professional interests also include the effects of solar magnetism on interplanetary space, on the planets, and on human technology. He has authored and edited over two hundred research articles and books, as well as popular science articles. Together with his wife, a physician, he wrote “Living with the stars”, a book for general audiences about the connections between the human body and the Universe. The discovery of exoplanets and the unfolding of fascinating insights into distant worlds triggered his latest book, “One of ten billion Earths: how we learn about our planet’s past and future from distant exoplanets”, published by Oxford University Press in 2018. He lives and works near Portland, Oregon.