Where are all the aliens? | Stephen Webb

Summary

Highlights

• Stephen Webb recounts a childhood UFO sighting that defied the laws of physics. 🛸
• Despite decades of searching, scientists like Frank Drake have found no evidence of extraterrestrial civilizations. 📡
• The universe is ancient and vast, posing a puzzling question: Why haven't we encountered extraterrestrial life yet? 🤔
• Barriers like habitability, abiogenesis, and technological advancement might prevent the emergence of communicative civilizations. 🚦
• The Rare Earth hypothesis presents the possibility that Earth is uniquely positioned to host advanced life. 🌏

Key Takeaways

• Stephen Webb shares a personal UFO sighting from his childhood, sparking a lifelong curiosity about extraterrestrial life. 👽
• Despite the vastness of the universe, we have not observed any alien civilizations, leading to countless speculations and theories. 🌌
• Webb discusses key barriers that civilizations would need to overcome to communicate across the galaxy. 🌠
• The Rare Earth hypothesis suggests that Earth might uniquely meet the conditions necessary for advanced life. 🌍
• Ultimately, Webb posits that humanity may be alone, highlighting the importance of our responsibility to preserve our planet. 🌎

Overview

Chapters

• 00:00 - 00:30: A Childhood UFO Sighting The chapter titled 'A Childhood UFO Sighting' recounts the narrator's memory of seeing a UFO during their childhood. At the age of eight or nine, while playing outside with a slightly older friend, they both witnessed a smooth, silver disc hovering in the sky above the houses. After observing it for a brief moment, they were astonished as it suddenly sped away at an incredible speed.
• 00:30 - 01:00: Skepticism and Psychology The chapter titled 'Skepticism and Psychology' explores the human tendency to be skeptical when confronted with claims that defy common understanding, such as sightings that ignore the laws of physics. It includes an anecdote about grown-ups being skeptical of a child's report of something unusual, only to later claim a sighting themselves after drinking. The narrative underscores how psychological principles reveal our brains' susceptibility to deception and self-delusion, drawing attention to how easily we can fool ourselves into seeing or believing things that aren't accurate.
• 01:00 - 01:30: The Question of Alien Presence In this chapter titled 'The Question of Alien Presence', the narrator reflects on a personal experience of possibly seeing an alien spacecraft, questioning whether it was a misinterpretation by the brain. The lingering wonder about the lack of visible flying saucers or detectable alien life is explored. Over thirty years, the narrator has engaged with numerous experts across various fields, yet a consensus on the existence or detection of alien life remains elusive. The chapter mentions Frank Drake's early efforts to search for alien signals, starting as far back as 1960.
• 01:30 - 02:00: The Age of the Universe This chapter introduces the concept of the age of the universe, which is approximately 13.8 billion years old. It uses the analogy of representing the universe's age as one year, placing the emergence of our species at about twelve minutes before midnight. The chapter also touches on the puzzling absence of evidence for alien activity despite the vast age of the universe.
• 02:00 - 03:00: Technological Advancements of Extraterrestrial Civilizations In this chapter, the author discusses the potential technological advancements of extraterrestrial civilizations, particularly those that may have originated before human civilization. The chapter opens with an analogy comparing the timeline of Western civilization to a few seconds, suggesting that extraterrestrial civilizations might have begun during a metaphorical 'summer.' These 'summer civilizations' could have developed advanced technologies that are still grounded in the laws of physics, such as those celebrated in technology conferences like TED. The chapter further explores the concept of self-replicating probes, which these advanced civilizations could potentially create and deploy.
• 03:00 - 03:30: Enrico Fermi's Question The chapter explores the hypothetical scenario where a civilization, perhaps alien, could potentially colonize the galaxy. It discusses the time implications of such an endeavor, suggesting that if they launched exploration probes at a given time, they might complete colonization in a relatively short period if considering galactic terms. The notion extends to intergalactic colonization, acknowledging the greater time demand but asserting its feasibility. The section challenges the reader by contemplating why we haven't noticed any recognizable activities if such colonization occurred, highlighting the paradox of the lack of evidence of alien life when theoretical models suggest their capability and time to have spread through the galaxy.
• 03:30 - 05:30: Key Barriers for Communicative Civilizations The chapter explores the paradox of why, despite the vast number of planets in the galaxy, there is no evident communication or sign of other civilizations. It speculates on the possibility of advanced civilizations creating structures like worldlets around stars to harness energy or collaborating on interstellar projects like a 'Wikipedia Galactica.' The central question posed is, 'Where is everybody?' as these civilizations are expected to exist considering the trillions of potential habitable planets.
• 05:30 - 06:30: The UFO Puzzle Chapter "The UFO Puzzle" discusses the factors necessary for a planet to support a communicative civilization. It highlights four key barriers that need to be overcome. The first barrier mentioned is habitability, which refers to the necessity of a terrestrial planet being in the habitable "Goldilocks zone". This chapter delves into these barriers in the context of exploring civilizations potentially being able to communicate across planets.
• 06:30 - 08:00: The Rare Earth Hypothesis The chapter discusses the concept of the Rare Earth Hypothesis, which posits that planets with conditions to support life like Earth are rare in the universe. It highlights the discovery of a planet within the habitable zone of Proxima Centauri, the closest star to our solar system, in 2016. The Breakthrough Starshot project aims to send probes to explore this planet. The chapter outlines the challenges of finding habitable planets, noting that many will either be too close to their stars, resulting in extreme heat, or too far, leading to freezing conditions. It introduces the concept of abiogenesis, the natural process of life arising from non-living matter, as a critical factor in a planet's habitability.
• 08:00 - 09:30: Complex Life and Civilization Barriers The chapter discusses the hurdles in the progression of life, specifically focusing on the transition from nonlife to life, and path to technological civilization. It highlights that although the fundamental components of life, such as amino acids, are found throughout the universe, the process of becoming life remains elusive. This conversation introduces the concept of barriers, outlining how certain planets may have these ingredients yet still not develop life. Furthermore, it includes the challenge of developing a technological civilization as an additional hurdle.
• 09:30 - 12:00: The Lone Civilization Theory This chapter discusses the concept that some alien intelligences might already reside on Earth, often overlooked in the form of animal intelligence. Studies from 2011 and 2010 present evidence of remarkable cognitive abilities of elephants and octopuses respectively - elephants showing cooperative problem solving skills and octopuses capable of recognizing different humans. However, despite their intelligence, these creatures cannot comprehend or engage in complex human endeavors like the Breakthrough Starshot project. The narrative highlights the solitary nature of human intelligence in undertaking specific scientific pursuits, such as space exploration, emphasizing that if humans were to disappear, other intelligent species would not continue our specific scientific legacy.
• 12:00 - 13:30: Humanity's Unique Opportunity The chapter "Humanity's Unique Opportunity" explores why space travel and communication across space might not be prevalent among advanced civilizations. The discussion suggests that evolution does not inherently aim for space travel as a goal. It posits that there may be worlds where life does not lead to advanced technology or chooses to focus on inner rather than outer space. Additionally, the chapter considers the possibility that civilizations might avoid contact with potentially more advanced and hostile neighbors.

Where are all the aliens? | Stephen Webb Transcription

• 00:00 - 00:30 I saw a UFO once. I was eight or nine, playing in the street with a friend who was a couple of years older, and we saw a featureless silver disc hovering over the houses. We watched it for a few seconds, and then it shot away incredibly quickly.
• 00:30 - 01:00 Even as a kid, I got angry it was ignoring the laws of physics. We ran inside to tell the grown-ups, and they were skeptical -- you'd be skeptical too, right? I got my own back a few years later: one of those grown-ups told me, "Last night I saw a flying saucer. I was coming out of the pub after a few drinks." I stopped him there. I said, "I can explain that sighting." (Laughter) Psychologists have shown we can't trust our brains to tell the truth. It's easy to fool ourselves. I saw something,
• 01:00 - 01:30 but what's more likely -- that I saw an alien spacecraft, or that my brain misinterpreted the data my eyes were giving it? Ever since though I've wondered: Why don't we see flying saucers flitting around? At the very least, why don't we see life out there in the cosmos? It's a puzzle, and I've discussed it with dozens of experts from different disciplines over the past three decades. And there's no consensus. Frank Drake began searching for alien signals back in 1960 --
• 01:30 - 02:00 so far, nothing. And with each passing year, this nonobservation, this lack of evidence for any alien activity gets more puzzling because we should see them, shouldn't we? The universe is 13.8 billion years old, give or take. If we represent the age of the universe by one year, then our species came into being about 12 minutes before midnight,
• 02:00 - 02:30 31st December. Western civilization has existed for a few seconds. Extraterrestrial civilizations could have started in the summer months. Imagine a summer civilization developing a level of technology more advanced than ours, but tech based on accepted physics though, I'm not talking wormholes or warp drives -- whatever -- just an extrapolation of the sort of tech that TED celebrates. That civilization could program self-replicating probes
• 02:30 - 03:00 to visit every planetary system in the galaxy. If they launched the first probes just after midnight one August day, then before breakfast same day, they could have colonized the galaxy. Intergalactic colonization isn't much more difficult, it just takes longer. A civilization from any one of millions of galaxies could have colonized our galaxy. Seems far-fetched? Maybe it is, but wouldn't aliens engage in some recognizable activity --
• 03:00 - 03:30 put worldlets around a star to capture free sunlight, collaborate on a Wikipedia Galactica, or just shout out to the universe, "We're here"? So where is everybody? It's a puzzle because we do expect these civilizations to exist, don't we? After all, there could be a trillion planets in the galaxy -- maybe more. You don't need any special knowledge to consider this question,
• 03:30 - 04:00 and I've explored it with lots of people over the years. And I've found they often frame their thinking in terms of the barriers that would need to be cleared if a planet is to host a communicative civilization. And they usually identify four key barriers. Habitability -- that's the first barrier. We need a terrestrial planet in that just right "Goldilocks zone,"
• 04:00 - 04:30 where water flows as a liquid. They're out there. In 2016, astronomers confirmed there's a planet in the habitable zone of the closest star, Proxima Centauri -- so close that Breakthrough Starshot project plans to send probes there. We'd become a starfaring species. But not all worlds are habitable. Some will be too close to a star and they'll fry, some will be too far away and they'll freeze. Abiogenesis --
• 04:30 - 05:00 the creation of life from nonlife -- that's the second barrier. The basic building blocks of life aren't unique to Earth: amino acids have been found in comets, complex organic molecules in interstellar dust clouds, water in exoplanetary systems. The ingredients are there, we just don't know how they combine to create life, and presumably there will be worlds on which life doesn't start. The development of technological civilization is a third barrier.
• 05:00 - 05:30 Some say we already share our planet with alien intelligences. A 2011 study showed that elephants can cooperate to solve problems. A 2010 study showed that an octopus in captivity can recognize different humans. 2017 studies show that ravens can plan for future events -- wonderful, clever creatures -- but they can't contemplate the Breakthrough Starshot project, and if we vanished today, they wouldn't go on to implement Breakthrough Starshot --
• 05:30 - 06:00 why should they? Evolution doesn't have space travel as an end goal. There will be worlds where life doesn't give rise to advanced technology. Communication across space -- that's a fourth barrier. Maybe advanced civilizations choose to explore inner space rather than outer space, or engineer at small distances rather than large. Or maybe they just don't want to risk an encounter with a potentially more advanced and hostile neighbor.
• 06:00 - 06:30 There'll be worlds where, for whatever reason, civilizations either stay silent or don't spend long trying to communicate. As for the height of the barriers, your guess is as good as anyone's. In my experience, when people sit down and do the math, they typically conclude there are thousands of civilizations in the galaxy. But then we're back to the puzzle: Where is everybody?
• 06:30 - 07:00 By definition, UFOs -- including the one I saw -- are unidentified. We can't simply infer they're spacecraft. You can still have some fun playing with the idea aliens are here. Some say a summer civilization did colonize the galaxy and seeded Earth with life ... others, that we're living in a cosmic wilderness preserve -- a zoo. Yet others -- that we're living in a simulation.
• 07:00 - 07:30 Programmers just haven't revealed the aliens yet. Most of my colleagues though argue that E.T. is out there, we just need to keep looking, and this makes sense. Space is vast. Identifying a signal is hard, and we haven't been looking that long. Without doubt, we should spend more on the search. It's about understanding our place in the universe. It's too important a question to ignore. But there's an obvious answer:
• 07:30 - 08:00 we're alone. It's just us. There could be a trillion planets in the galaxy. Is it plausible we're the only creatures capable of contemplating this question? Well, yes, because in this context, we don't know whether a trillion is a big number. In 2000, Peter Ward and Don Brownlee proposed the Rare Earth idea. Remember those four barriers that people use to estimate the number of civilizations?
• 08:00 - 08:30 Ward and Brownlee said there might be more. Let's look at one possible barrier. It's a recent suggestion by David Waltham, a geophysicist. This is my very simplified version of Dave's much more sophisticated argument. We are able to be here now because Earth's previous inhabitants enjoyed four billion years of good weather -- ups and downs but more or less clement. But long-term climate stability is strange, if only because astronomical influences
• 08:30 - 09:00 can push a planet towards freezing or frying. There's a hint our moon has helped, and that's interesting because the prevailing theory is that the moon came into being when Theia, a body the size of Mars, crashed into a newly formed Earth. The outcome of that crash could have been a quite different Earth-Moon system. We ended up with a large moon and that permitted Earth to have both a stable axial tilt
• 09:00 - 09:30 and a slow rotation rate. Both factors influence climate and the suggestion is that they've helped moderate climate change. Great for us, right? But Waltham showed that if the moon were just a few miles bigger, things would be different. Earth's spin axis would now wander chaotically. There'd be episodes of rapid climate change -- not good for complex life. The moon is just the right size: big but not too big.
• 09:30 - 10:00 A "Goldilocks" moon around a "Goldilocks" planet -- a barrier perhaps. You can imagine more barriers. For instance, simple cells came into being billions of years ago ... but perhaps the development of complex life needed a series of unlikely events. Once life on Earth had access to multicellularity and sophisticated genetic structures, and sex, new opportunities opened up: animals became possible. But maybe it's the fate of many planets
• 10:00 - 10:30 for life to settle at the level of simple cells. Purely for the purposes of illustration, let me suggest four more barriers to add to the four that people said blocked the path to communicative civilization. Again, purely for the purposes of illustration, suppose there's a one-in-a-thousand chance of making it across each of the barriers. Of course there might be different ways of navigating the barriers, and some chances will be better than one in a thousand.
• 10:30 - 11:00 Equally, there might be more barriers and some chances might be one in a million. Let's just see what happens in this picture. If the galaxy contains a trillion planets, how many will host a civilization capable of contemplating like us projects such as Breakthrough Starshot? Habitability -- right sort of planet around the right sort of star -- the trillion becomes a billion. Stability -- a climate that stays benign for eons --
• 11:00 - 11:30 the billion becomes a million. Life must start -- the million becomes a thousand. Complex life forms must arise -- the thousand becomes one. Sophisticated tool use must develop -- that's one planet in a thousand galaxies. To understand the universe, they'll have to develop the techniques of science and mathematics -- that's one planet in a million galaxies. To reach the stars, they'll have to be social creatures, capable of discussing abstract concepts with each other using complex grammar --
• 11:30 - 12:00 one planet in a billion galaxies. And they have to avoid disaster -- not just self-inflicted but from the skies, too. That planet around Proxima Centauri, last year it got blasted by a flare. One planet in a trillion galaxies, just as in the visible universe. I think we're alone. Those colleagues of mine who agree we're alone often see a barrier ahead --
• 12:00 - 12:30 bioterror, global warming, war. A universe that's silent because technology itself forms the barrier to the development of a truly advanced civilization. Depressing, right? I'm arguing the exact opposite. I grew up watching "Star Trek" and "Forbidden Planet," and I saw a UFO once, so this idea of cosmic loneliness I certainly find slightly wistful.
• 12:30 - 13:00 But for me, the silence of the universe is shouting, "We're the creatures who got lucky." All barriers are behind us. We're the only species that's cleared them -- the only species capable of determining its own destiny. And if we learn to appreciate how special our planet is, how important it is to look after our home and to find others, how incredibly fortunate we all are simply to be aware of the universe,
• 13:00 - 13:30 humanity might survive for a while. And all those amazing things we dreamed aliens might have done in the past, that could be our future. Thank you very much. (Applause)