The Biological Universe

Current state of play in astrobiology, including exoplanets and their atmospheres, habitable zones and the likelihood of evolution elsewhere.

Are we alone in the universe, or are there other life forms 'out there'? This is one of the most scientifically and philosophically important questions that humanity can ask. Now, in the early 2020s, we are tantalizingly close to an answer. As this book shows, the answer will almost certainly be that life forms are to be found across the Milky Way and beyond. They will be thinly spread, to be sure. Yet the number of inhabited planets probably runs into the trillions. Some are close enough for us to detect evidence of life by analysing their atmospheres. This evidence may be found within a couple of decades. Its arrival will be momentous. But even before it arrives we can anticipate what life elsewhere will be like by examining the ecology and evolution of life on Earth. This book considers the current state of play in relation to these titanic issues.

Autorentext
Wallace Arthur is an evolutionary biologist who is fascinated by the possibility of evolution occurring on other planets. His first book on this subject was Life through Time and Space (2017), of which the Astronomer Royal Sir Arnold Wolfendale said: 'brilliant and thought-provoking in every way'. The Biological Universe is the sequel.

Zusammenfassung
This book is for everyone with an interest in whether there is extraterrestrial life. Recent discoveries of planets beyond the solar system (more than 4000 of them) suggest that the question is not 'whether?' but 'where?'. This book enables general readers to understand current endeavours to answer this question and the related one of 'what kind?'

Inhalt

Part I. Painting Big Pictures: 1. A tree with millions of twigs; 2. A galaxy with billions of planets; 3. The likelihood of other trees; Part II. Life Here, Implications for Elsewhere: 4. A thin sliver of existence; 5. Energy and life; 6. Habitats and life; 7. Skeletons and life; 8. Intelligence and life; Part III. Planetary Systems and Life: 9. Types of planetary system; 10. Habitable zones; 11. Other habitability factors; 12. How many inhabited planets?; Part IV. Discovering Life: 13. On the repeatability of evolution; 14. Candidate planets; 15. Atmospheric signatures; 16. Radio and life; 17. Sixty years of SETI; Part V. Beyond the Milky Way: 18. The physical universe; 19. The biological universe; 20. The intelligent universe; Bibliography; Acknowledgements.