Do Alien Civilizations Inevitably ‘Go Green’?

In the famous words of Arthur C. Clarke, “Any sufficiently advanced technology is indistinguishable from magic.” This phrase is often quoted to express the idea that an alien civilization which may be thousands or millions of years older than us would have technology so far ahead of ours that to us it would appear to be “magic.” Now, a variation of that thought has come from Canadian science fiction writer Karl Schroeder, who posits that ”any sufficiently advanced technology is indistinguishable from nature.” The reasoning is that if a civilization manages to exist that long, it would inevitably “go green” to such an extent that it would no longer leave any detectable waste products behind. Its artificial signatures would blend in with those of the natural universe, making it much more difficult to detect them by simply searching for artificial constructs versus natural ones. The idea has been proposed as an explanation for why we haven’t found them yet, based on the premise that such advanced societies would have visited and colonized our entire galaxy by now (known as the Fermi Paradox). The question becomes more interesting in light of the fact that astronomers now estimate that there are billions of other planets in our galaxy alone. If a civilization reaches such a “balance with nature” as a natural progression, it may mean that traditional methods of searching for them, like SETI, will ultimately fail. Of course, it is possible, perhaps even likely, that civilizations much older than us would have advanced far beyond radio technology anyway. SETI itself is based on the assumption that some of them may still be using that technology. Another branch of SETI is searching for light pulses such as intentional beacons as opposed to radio signals. But even other alternate searches, such as SETT (Search for Extraterrestrial Technology), may not pan out either, if this new scenario is correct. SETT looks for things like the spectral signature of nuclear fission waste being dumped into a star, or leaking tritium from alien fusion powerplants. Another solution to the Fermi Paradox states that advanced civilizations will ultimately destroy themselves. Before they do though, they could have already sent out robotic probes to many places in the galaxy. If those probes were technologically savvy enough to self-replicate, they could have spread themselves widely across the cosmos. If there were any in our solar system, we could conceivably find them. Yet this idea could also come back around to the new hypothesis – if these probes were advanced enough to be truly “green” and not leave any environmental traces, they might be a lot harder to find, blending in with natural objects in the solar system. It’s an intriguing new take on an old question. It can also be taken as a lesson – if we can learn to survive our own technological advances long enough, we can ultimately become more of a green civilization ourselves, co-existing comfortably with the natural universe around us. Source: Article.
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Moon formation: Was it a 'hit and run' accident?

Computer simulations suggest a large, fast-moving body impacted the Earth to create the Moon 
Scientists have proposed a fresh idea that in the process of Moon formation the crash happened with a much larger, faster body than previously thought. What is certain is that some sort of impact from another body freed material from the young Earth and the resulting debris coalesced into today's Moon. But the exact details of the impactor's size and speed have remained debatable. The report will be published online in Icarus. Such theories need to line up with what we know about the Moon, about the violent processes that set off the creation of moons, and what computer simulations show about the more sedate gravitational "gathering-up" that finishes the job. In recent years, scientists' best guess for how the Moon formed has been that a relatively slowly moving, Mars-sized body called Theia crashed into the very young Earth. That would have heated both of them up and released a vast cloud of molten material, much of which cooled and clumped together to give rise to the Moon. That would suggest that the Moon is made up of material from both the early Earth and from Theia, which should be somewhat different from one another. What complicates that story is a number of observations of "isotopic compositions", taken from the Earth and from lunar samples. While the Moon has an iron core like Earth, it does not have the same fraction of iron - and computer models supporting the Theia impact idea show just the same thing. However, the ratio of the Earth's and the Moon's oxygen isotopes is nearly identical and a fresh analysis of lunar samples taken by the Apollo missions showed that the Moon and the Earth shared an uncannily similar isotope ratio of the metal titanium. That, they said, gave weight to the idea that the Moon was somehow cleaved from the Earth itself. Now, Andreas Reufer, of the Center for Space and Habitability in Bern, Switzerland, and colleagues have run computer simulations that suggest another possibility: that a far larger and faster-moving body made an even more glancing blow with the young Earth. They said this body would have lost only a small amount of material and most of it would have continued on after the "hit-and-run". That results in a much hotter disc of debris from the collision, but matches up with what would be needed to make a Moon-sized body. More research, analyses and simulations would be needed to settle the debate.Source: Sam Daily Times
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