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The Great Filter

The Great Filter
Sept. 15, 1998 by Robin Hanson Humanity seems to have a bright future, i.e., a non-trivial chance of expanding to fill the universe with lasting life. But the fact that space near us seems dead now tells us that any given piece of dead matter faces an astronomically low chance of begating such a future. Introduction Fermi, Dyson, Hart, Tipler, and others [Finney & Jones, Dyson 66, Hart 75, Tipler 80] have highlighted the relevance to SETI (the search for extraterrestrial intelligence) of the "The Great Silence" [Brin 83] (also known as the Fermi paradox), the fact that extraterrestrials haven't substantially colonized Earth yet. The Great Silence must force us to revise a standard view in one or more area of biology, astronomy, physics, or the social sciences. Life Will Colonize So far, life on earth seems to have adapted its technology to fill every ecological niche it could. This phenomena is easily understood from an evolutionary perspective. The Data Point The Great Filter Related:  UFOs? and Life in the Beyond

Why Habitable Exoplanets Are Bad News for Humanity's Future - The Crux This article was originally published on The Conversation. Last week, scientists announced the discovery of Kepler-186f, a planet 492 light years away in the Cygnus constellation. Kepler-186f is special because it marks the first planet almost exactly the same size as Earth orbiting in the “habitable zone” – the distance from a star in which we might expect liquid water, and perhaps life. What did not make the news, however, is that this discovery also slightly increases how much credence we give to the possibility of near-term human extinction. The Great Filter is an argument that attempts to resolve the Fermi Paradox: why have we not found aliens, despite the existence of hundreds of billions of solar systems in our galactic neighborhood in which life might evolve? This apparent absence of thriving extraterrestrial civilizations suggests that at least one of the steps from humble planet to interstellar civilization is exceedingly unlikely. Are We Alone? Or Is the Filter Ahead of Us?

The Fermi Paradox - Wait But Why PDF: We made a fancy PDF of this post for printing and offline viewing. Buy it here. (Or see a preview.) Everyone feels something when they’re in a really good starry place on a really good starry night and they look up and see this: Some people stick with the traditional, feeling struck by the epic beauty or blown away by the insane scale of the universe. Personally, I go for the old “existential meltdown followed by acting weird for the next half hour.” Physicist Enrico Fermi felt something too—”Where is everybody?” A really starry sky seems vast—but all we’re looking at is our very local neighborhood. Galaxy image: Nick Risinger When confronted with the topic of stars and galaxies, a question that tantalizes most humans is, “Is there other intelligent life out there?” As many stars as there are in our galaxy (100 – 400 billion), there are roughly an equal number of galaxies in the observable universe—so for every star in the colossal Milky Way, there’s a whole galaxy out there. 1. 2.

Our Best Bet for Colonizing Space May Be Printing Humans on Other Planets Assuming human deep space travel turns out to be not just incredibly dangerous, but perhaps “crazy idiotic" and "laughable," as Harvard biologist Gary Ruvkun put it, the tenacious dream of an interstellar civilization forces some out-of-the box thinking. What if, instead of rocketing humans to other planets, we made an exact copy on site? Adam Steltzner, the lead engineer on the NASA JPL's Curiosity rover mission, believes that to send humans to distant planets, we may need to do one of two things: look for ways to game space-time—traveling through wormholes and whatnot—or rethink the fundamental idea of "ourselves." "Our best bet for space exploration could be printing humans, organically, on another planet," said Steltzner on stage at Smithsonian Magazine’s Future Is Now conference in Washington, DC this month. The "printing" idea starts out by encoding human genetic information in bacteria so that our DNA can hitch a ride to another planet. Beautiful, fantastic, and totally bonkers.

Astrobiological phase transition: towa... [Orig Life Evol Biosph. 2008] Point and Shoot - Issue 3: In Transit The history of human exploration has always been tied to the search for a destination. Space travel is no different: The Apollo program, which ferried humans to the moon, was not only a scientific and technical achievement, but also an exercise in planting flags and leaving bootprints. Yet proposals are now brewing to launch missions to empty dots in the vastness of space, albeit ones with very special properties. Take any planet in orbit around a star, or any moon that spins around a planet. In each of these systems there will be five spots, arranged in a geometrical configuration that resembles the points of an archer’s drawn bow, where the combined gravitational fields and centrifugal force of the bodies’ rotation cancel out. These are zones of hidden equilibrium, gravitational lacunae amid the ceaseless movement of celestial bodies. The name “Lagrange points” may be a bit of a misnomer, as they vary in character and stability.

SETI Articles Shells Around Suns May Have Been Built Science News Letter, June 18, 1960, page 389, Astronomy Intelligent beings in another solar system could have hidden their sun by knocking their planets apart and using the pieces to build a hollow ball around their sun. Dr. A hollow ball built around the sun would solve the space and energy problems. A search for such infrared radiation should be coordinated with, Project Ozma, a program now underway for detecting artificial radio waves from nearby stars, Dr. Using our own solar system as an example, Dr. To trap the energy, earthlings could knock apart the planet Jupiter and rearrange it as a hollow ball about 10 feet thick with a diameter twice the size of earth's orbit. Dr. Search for Artificial Stellar Sources of Infrared Radiation Freeman John Dyson, Science, Vol. 131, June 3, 1960, pp. 1667-1668. We have no direct knowledge of the material conditions which these beings would encounter in their search for lebensraum. References G. Eugene A.

Close Encounters Of The Radio Kind? Mystery Bursts Baffle Astronomers hide captionScientists say a brief burst of radio activity has been detected at the Arecibo radio telescope in Puerto Rico. This new report resembles previous activity detected in Australia, which has scientist debating possible causes, including solar flares, blitzars, or something even more mysterious. Brian Negin/iStockphoto Scientists say a brief burst of radio activity has been detected at the Arecibo radio telescope in Puerto Rico. This new report resembles previous activity detected in Australia, which has scientist debating possible causes, including solar flares, blitzars, or something even more mysterious. Astronomers have a mystery on their hands. Right now, astronomers have no idea what's causing these bursts or where they're coming from. Australian Recordings Inspire Curiosity And Doubt hide captionThe Parkes Observatory, in New South Wales, Australia, first detected the brief, intense bursts of radio waves in 2007. Ian Sutton/Flickr But there was one lingering doubt.

A New Thermodynamics Theory of the Origin of Life Why does life exist? Popular hypotheses credit a primordial soup, a bolt of lightning and a colossal stroke of luck. But if a provocative new theory is correct, luck may have little to do with it. Instead, according to the physicist proposing the idea, the origin and subsequent evolution of life follow from the fundamental laws of nature and “should be as unsurprising as rocks rolling downhill.” From the standpoint of physics, there is one essential difference between living things and inanimate clumps of carbon atoms: The former tend to be much better at capturing energy from their environment and dissipating that energy as heat. Jeremy England, a 31-year-old assistant professor at the Massachusetts Institute of Technology, has derived a mathematical formula that he believes explains this capacity. Kristian Peters Cells from the moss Plagiomnium affine with visible chloroplasts, organelles that conduct photosynthesis by capturing sunlight. Courtesy of Jeremy England Wilson Bentley

Alpha Centauri B may have "superhabitable" worlds Since Earth is the only known inhabited planet and we happen to live here, it’s only natural to regard it as the ideal place for life to exist, and to assume that another life-bearing planet would be fairly similar. However, that is not the opinion of scientists René Heller and John Armstrong who contend that there might be a planet even more suitable for life than Earth 4.3 light years away orbiting the star Alpha Centauri B. View all The nice thing about having a hypothetical “superhabitable” planet revolving around Alpha Centauri B, which is part of a triple star system, is that it makes it a lot easier to indulge in a bit of a thought experiment based on the arguments put forward by Heller, of the Department of Physics and Astronomy, McMaster University, Hamilton in Ontario, Canada, and Armstrong, of the Department of Physics, Weber State University in Ogden, Utah. Imagine we’re in a spaceship approaching the planet in question. If you want a habitable planet, you need the right sun.

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