Book If the universe is full of extraterrestrials... where is everyone?

If the universe is full of extraterrestrials... where is everybody?

If there are some 400 billion stars in our Galaxy alone, and about 400 billion galaxies in the universe, it seems reasonable that somewhere out there, in a cosmos 14 billion years old, there is, or ever was, at least one civilization as advanced as ours. The sheer immensity of the numbers almost compels us to admit the veracity of this hypothesis. But why, then, have we found no sign, no message, no artifact from these extraterrestrials?

In this thoroughly revised and expanded edition of Stephen Webb's well-known work, the author breaks down in detail the 75 most convincing and interesting (for the moment) solutions to the famous Fermi paradox: if the numbers point strongly to the existence of extraterrestrial civilizations, why haven't we found any sign of them?

• Translator: Dulcinea Otero-Piñeiro
• Collection: Astronomy
• Subject: Natural sciences and techniques, Astronomy
• Language: Spanish
• Publication date: 17-09-2018
• Pages: 496
• Dimensions: Width 17 cm, Height24 cm
• Edition: 1
• About the author: Physicist Stephen Webb is known as an author of popular science books. He has published Measuring the Universe - The Cosmological Distance Ladder (1999), Out of this World - Colliding Universes, Branes, Strings, and Other Wild Ideas of Modern Physics (2004) and New Eyes on the Universe - Twelve Cosmic Mysteries and the Tools We Need to Solve Them (2012).

Table of Contents:

• 1 Where is everybody?
• 2 Fermi and the paradoxes
• Physicist Enrico Fermi
• Paradoxes
• The Fermi paradox
• 3 They are (or have been) here
• Solution 1: They are here and call themselves Hungarians
• Solution 2: They are here and they call themselves politicians
• Solution 3: They are throwing stones at Radivoje Lajić
• Solution 4: They observe us from UFOs
• Solution 5: They have been here and have left signs of their presence
• presence
• Solution 6: They exist and they are us: we are all aliens!
• Solution 7: The zoo argument
• Solution 8: The interdiction argument
• Solution 9: The planetarium hypothesis
• Solution 10: God exists
• 4 They exist, but we have not yet seen them or heard from them
• Solution 11: The stars are far away
• Solution 12: They have not had time to reach us
• Solution 13: The focus of a percolation theory
• Solution 14: Wait a minute
• Solution 15: The limit of the light cage
• Solution 16: They change their minds
• Solution 17: We are solar chauvinists
• Solution 18: Aliens are green
• Solution 19: They stay at home..
• Solution 20: ...and surf the Net
• Solution 21: They reject imperialism
• Solution 22: Bracewell-Von Neumann Probes
• Solution 23: Panspermia of information
• Solution 24: Berserkers
• Solution 25: They send signals, but we don't know how to listen to them
• Solution 26: They send signals, but we don't know how often to listen to them
• Solution 27: They send signals, but we don't know where to look
• Solution 28: The signal is already in the data
• Solution 29: We haven't been listening long enough
• Solution 30: They're sending signals, but we're not receiving them
• Solution 31: Everyone is listening and no one is broadcasting Solution 32: They don't have any
• solution 32: They have no desire to communicate
• Solution 33: They have developed different mathematics
• Solution 34: They're calling us, but we don't recognize the signal
• Solution 35: Message in a bottle
• Solution 36: Wow... the apocalypse!
• Solution 37: Oh... the apocalypse!
• Solution 38: Heat wave
• Solution 39: Apocalypse, when?
• Solution 40: Cloudy skies abound
• Solution 41: It doesn't get any better than this
• Solution 42: They are remote learners
• Solution 43: They're out there somewhere, but the universe is stranger than we imagine
• Solution 44: Intelligence is not permanent
• Solution 45: We live in a post-biological universe
• Solution 46: They live in the vicinity of black holes
• Solution 47: They reach the singularity
• Solution 48: The transcendence hypothesis
• Solution 49: The migration hypothesis
• Solution 50: There are an infinite number of civilizations, but only one within our particle horizon: us
• 5 They do not exist
• Solution 51: The universe is here for us
• Solution 52: The canonical artifact
• Solution 53: Life could only have arisen recently
• Solution 54: Planetary systems are in short supply
• Solution 55: Rocky planets are in short supply
• Solution 56: A water-based solution
• Solution 57: Habitable zones are always narrow strips
• Solution 58: Earth is the first
• Solution 59: The Earth has an optimal "evolutionary pumping"
• Solution 60: The Galaxy is a dangerous place
• Solution 61: A planetary system is a dangerous place
• Solution 62: Earth's plate tectonic system is unique
• Solution 63: The Moon is unique
• Solution 64: The genesis of life is an oddity
• Solution 65: The genesis of life is a rarity (revised)
• Solution 66: The twin planets of a perfect planet are rare
• Solution 67: The transition from prokaryote to eukaryote is a rarity
• Solution 68: Species that make tools are a rarity
• Solution 69: High technology is not inevitable
• Solution 70: Intelligence at a human level is a rarity
• Solution 71: Language is a unique trait of humans
• Solution 72: Science is not inevitable
• Solution 73: Consciousness is not inevitable
• Solution 74: Gaia, God or Goldilocks?
• 6 Conclusion
• Solution 75: Fermi's paradox solved..
• Notes
• Bibliography
• Alphabetical index

If the universe is full of extraterrestrials... where is everybody?