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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. There thus exists a great filter between death and expanding lasting life, and humanity faces the ominous question: how far along this filter are we? Combining standard stories of biologists, astronomers, physicists, and social scientists would lead us to expect a much smaller filter than we observe. 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. Life Will Colonize The Data Point The Great Filter

http://hanson.gmu.edu/greatfilter.html

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NASA Chief Scientist Ellen Stofan Predicts We'll Find Signs Of Alien Life Within 10 Years Ellen Stofan (NASA) NASA's top scientist predicts that we'll find signs of alien life by 2025, with even stronger evidence for extraterrestrials in the years that follow. "I think we're going to have strong indications of life beyond Earth within a decade, and I think we're going to have definitive evidence within 20 to 30 years," NASA chief scientist Ellen Stofan said Tuesday during a panel event on water in the universe. "We know where to look. We know how to look," Stofan added. "In most cases we have the technology, and we're on a path to implementing it.

Lab gets funding to put 3D goggles on praying mantises It sounds like the kind of research project that a future a Congressman might hold up as an example of wasteful government spending: gluing a praying mantis to a stick and putting mini-3D goggles on it. But this project is very real and pretty neat, and it should actually tell us something about neurobiology. (Plus, it's all being funded by a private foundation.) Praying mantises aren't just unusually large insects; they're extremely efficient predators that have even been known to catch and eat birds. This requires both a lightning-quick strike and the visual acuity to direct the strike towards the prey.

The Billion-Year Technology Gap: Could One Exist? (The Weekend Feature) The odds of there being only one single planet that evolved life among all that unfathomable vastness seems so incredible that it is all but completely irrational to believe. But then "where are they?" asked physicist Enrico Fermi while having lunch with his colleagues in 1950. Fermi reasoned, if there are other advanced extraterrestrial civilizations, then why is there no evidence of such, like spacecraft or probes floating around the Milky Way. His question became famously known as the Fermi Paradox. 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.”

MIT study on exoplanet orbits may narrow parameters in search for life A team of researchers from MIT and Aarhus University, Denmark, have discovered that Earth-sized exoplanets orbit their parent stars in the same way that our planet orbits our own Sun – maintaining a roughly equidistant circular orbit. The discovery further narrows the characteristics of worlds that could potentially play host to extraterrestrial life. Astronomers have long wondered whether the highly-structured orbital trend displayed in our solar system was simply the norm, or the result of an amazing coincidence. A new study that examined the orbits of 74 exoplanets orbiting 28 distant stars appears to put the question to rest. The team created model orbits for the exoplanets by observing the characteristics of specially selected parent stars with predetermined characteristics. By having a knowledge of the mass and radius of a host star, the researchers could extrapolate the speed at which a potential Earth-like planet would travel around it, assuming that its orbit was circular.

Mantis Shrimp-Inspired Material is Stronger than Airplanes The mighty, mighty mantis shrimp is a colorful and fearsome predator that can smash its opponent (and aquariums walls) to pieces using its arms that are covered with hard exoskeleton. Researchers hoping to harness its power have now created a material that’s stronger than what’s used in airplane frames. Also known as a stomatopd (Odontodactylus scyllarus), the 4 to 6-inch long smashing predator has a fist-like “mineralized dactyl club” that can withstand thousands of high-velocity blows, which it delivers to its prey. The force created by the impact of its club is more than 1,000 times its own weight, and underwater, the club accelerates faster than a 22-caliber bullet. Much of the impact resistance and shock absorbance is thanks to the spiraling (or helicoidal) arrangement of mineralized fiber layers on an area of the club called the endocuticle region.

Advanced alien civilizations, have we already found some? « Astrobioloblog Lots of scientists think our Galaxy should be full of advanced alien civilizations (see the Drake Equation and Fermi Paradox posts). But when they’ve looked the Galaxy appears to be quiet and lonely. Where are all the alien civilizations they ask? 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. Alien Transit Systems May Be a Giveaway in the Search for ET Avi Loeb has an unorthodox new idea about how to search for alien civilizations—and it is hardly a surprise. Loeb, who chairs the astronomy department at Harvard University, has spent much of his career thinking about how the first stars came to life after the big bang, and how galaxies were born. But lately he’s become intrigued with the search for extraterrestrial intelligence, or SETI, and he tends to come at it in unusual ways. Over the past few years, for example, Loeb has suggested searching for aliens by looking for artificial lighting on Pluto, in the admittedly unlikely event that extraterrestrials (ET) have set up an outpost there. He also has proposed trying to detect industrial pollution on distant exoplanets. His latest notion, laid out in a paper he and a co-author just put online: We should look for the microwave beams ETs might use to send light sails wafting between the planets in their home solar systems.

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