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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt'>From:</span></b><span style='font-size:14.0pt'> extropy-chat <extropy-chat-bounces@lists.extropy.org> <b>On Behalf Of </b>John Clark<br><b>…</b></span><span style='font-size:14.0pt'><br>===<br><br>>…For years physicists debated if gravitational waves were real, some said they contained no energy and so were just a mathematical artifact of no physical significance. But then in 1957 Richard Feynman came up with a thought experiment that showed gravitational waves must contain energy and thus must have real physical effects, the sticky bead argument…<o:p></o:p></span></p><div><div><div><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>The LIGO experiment is hardcore evidence of Feynman’s notion. The long tubes were clearly compressed by the passing gravity waves. The steel is very close to perfectly elastic but are not perfectly elastic: compressing and expanding a pipe even a fraction of a proton width would create friction, and that energy hasta come from somewhere.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>>… It sure seems to me it could also show that work can be extracted from the expansion of the universe. John K Clark<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>I don’t see why not, and can even expand a bit on that expansion argument.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>General relativity has a term in there for calculating the inertial frame-dragging phenomenon measured by Gravity Probe B. I had the privilege of working on that experiment back in 1989. The gyro precession was found, and that precession requires a torque thru an angle, and that is work, which is energy. It looks to me like inertial frame-dragging would strengthen your argument that expansion of the universe is converting energy. What I don’t know is if (or how) work could be extracted from the process. That process might define the entropy level beyond which energy cannot be extracted because there is no higher entropy level to reach.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>Oh how I wish I understood the subtleties of the second law better than I do. There is so much truth to be found there.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt'>spike <o:p></o:p></span></p></div></div></div></div></body></html>