If the Universe Is Teeming with Aliens ... Where Is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life Book

PREFACE

FIGURE CREDITS

CHAPTER 1 WHERE IS EVERYBODY?

CHAPTER 2 OF FERMI AND PARADOX

CHAPTER 3 THEY ARE HERE

Solution 1 They Are Here and They Call Themselves Hungarians

Solution 2 They Are Here and Are Meddling in Human Affairs

Solution 3 They Were Here and Left Evidence of Their Presence

Solution 4 They Exist and They Are Us -- We Are All Aliens!

Solution 5 The Zoo Scenario

Solution 6 The Interdict Scenario

Solution 7 The Planetarium Hypothesis

Solution 8 God Exists

CHAPTER 4 THEY EXIST BUT HAVE NOT YET COMMUNICATED

Solution 9 The Stars Are Far Away

Solution 10 They Have Not Had Time to Reach Us

Solution 11 A Percolation Theory Approach

Solution 12 Bracewell-von Neumann Probes

Solution 13 We Are Solar Chauvinists

Solution 14 They Stay at Home . . .

Solution 15 . . . and Surf the Net

Solution 16 They Are Signaling But We Do Not Know How to Listen

Solution 17 They Are Signaling But We Do Not Know at Which Frequency to Listen

Solution 18 Our Search Strategy Is Wrong

Solution 19 The Signal Is Already There in the Data

Solution 20 We Have Not Listened Long Enough

Solution 21 Everyone Is Listening, No One Is Transmitting

Solution 22 Berserkers

Solution 23 They Have No Desire to Communicate

Solution 24 They Develop a Different Mathematics

Solution 25 They Are Calling But We Do Not Recognize the Signal

Solution 26 They Are Somewhere But the Universe Is Stranger Than We Imagine

Solution 27 A Choice of Catastrophes

Solution 28 They Hit the Singularity

Solution 29 Cloudy Skies Are Common

Solution 30 Infinitely Many ETCs Exist But Only One Within Our Particle Horizon: Us

CHAPTER 5 THEY DO NOT EXIST

Solution 31 The Universe Is Here for Us

Solution 32 Life Can Have Emerged Only Recently

Solution 33 Planetary Systems Are Rare

Solution 34 We Are the First

Solution 35 Rocky Planets Are Rare

Solution 36 Continuously Habitable Zones Are Narrow

Solution 37 Jupiters Are Rare

Solution 38 Earth Has an Optimal "Pump of Evolution"

Solution 39 The Galaxy Is a Dangerous Place

Solution 40 A Planetary System Is a Dangerous Place

Solution 41 Earth's System of Plate Tectonics Is Unique

Solution 42 The Moon Is Unique

Solution 43 Life's Genesis Is Rare

Solution 44 The Prokaryote-Eukaryote Transition Is Rare

Solution 45 Toolmaking Species Are Rare

Solution 46 Technological Progress Is Not Inevitable

Solution 47 Intelligence at the Human Level Is Rare

Solution 48 Language Is Unique to Humans

Solution 49 Science Is Not Inevitable

CHAPTER 6 CONCLUSION

Solution 50 The Fermi Paradox Resolved . . .

CHAPTER 7 NOTES AND FURTHER READING

CHAPTER 8 REFERENCES

INDEX