Friday, April 22, 2016

April 22, 2016 -- A Quick Run Around the Web


Other Stuff:
... If the Silver Creek Caldera erupted for 2.5 to 10 hours at a sustained rate of 38 to 150 million cubic meters per second, then these flows could move blocks even moving at only a few tens of kilometers per hour. Now, that eruption rate is huge, tens to hundreds of times more than Pinatubo, Tambora or Novarupta, some of the biggest eruptions of the last few centuries.
    This means that the eruption of the Peach Springs Tuff was at least as large if not larger than the super-eruptions like Toba or Taupo. Yet, if you were 150 kilometers from the eruption, you might have upwards of 10 hours to get out of harm’s way (well, at least out of the way of the massive pyroclastic flows—the resulting ash fall and climate cooling is a little trickier to handle).
      • Related: "Capitalism and the Minimum Wage: 'I Got Mine, Screw You.'"--Fred On Everything. "An economic system that works reasonably well when there are lots of simple jobs doesn’t when there aren’t. In particular, the large number of people at IQ 90 and below will increasingly be simply unnecessary."
        If a company or a government department were in charge of the record, it would be vulnerable – if the company went bust or the government department shut down, for example. But with a distributed record there is no single point of vulnerability. It is decentralised. At times, some computers might go awry, but that doesn’t matter. The copies on all the other computers and their unanimous approval for new information to be added will mean the record itself is safe.
          This is possibly the most significant and detailed record in all history, an open-source structure of permanent memory, which grows organically. It is known as the blockchain. It is the breakthrough tech behind the digital cash system, Bitcoin, but its impact will soon be far wider than just alternative money.
            McCulloch’s idea is that inertia arises from an effect predicted by general relativity called Unruh radiation. This is the notion that an accelerating object experiences black body radiation. In other words, the universe warms up when you accelerate.
              According to McCulloch, inertia is simply the pressure the Unruh radiation exerts on an accelerating body.
                That’s hard to test at the accelerations we normally observe on Earth. But things get interesting when the accelerations involved are smaller and the wavelength of Unruh radiation gets larger.
                  At very small accelerations, the wavelengths become so large they can no longer fit in the observable universe. When this happens, inertia can take only certain whole-wavelength values and so jumps from one value to the next. In other words, inertia must quantized at small accelerations.
                    McCulloch says there is observational evidence for this in the form of the famous fly by anomalies. These are the strange jumps in momentum observed in some spacecraft as they fly past Earth toward other planets. That’s exactly what his theory predicts.
                      Testing this effect more carefully on Earth is hard because the accelerations involved are so small. But one way to make it easier would be to reduce the size of allowed wavelengths of Unruh radiation. “This is what the EmDrive may be doing,” says McCulloch.
                        The idea is that if photons have an inertial mass, they must experience inertia when they reflect. But the Unruh radiation in this case is tiny. So small in fact that it can interact with its immediate environment. In the case of the EmDrive, this is the truncated cone.
                          The cone allows Unruh radiation of a certain size at the large end but only a smaller wavelength at the other end. So the inertia of photons inside the cavity must change as they bounce back and forth. And to conserve momentum, this must generate a thrust.

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                          A New Defensive Pistolcraft Post ...

                            ... from Jon Low . There is a lot of good stuff in this post, and Jon seems (at least to me) to have included much more of his own comment...