tag:blogger.com,1999:blog-8515829.post4105559615931577539..comments2024-03-28T00:27:14.676-07:00Comments on Irons in the Fire: Oh wow, Sheldon must be having a cowFirehandhttp://www.blogger.com/profile/04562365951182027709noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-8515829.post-9042162491731834782011-11-27T18:33:05.919-08:002011-11-27T18:33:05.919-08:00FTL is quite unlikely here. Far more likely is tha...FTL is quite unlikely here. Far more likely is that there's an error in their time base, which came from GPS satellites - but I think with various corrections to attempt to improve upon the design accuracy of GPS. GPS is not intended to be accurate to one inch, which means that timing errors of over one nanosecond are acceptable. IIRC, the anomaly in the measured neutrino transit times is far less than 1 nanosecond.<br /><br />GPS satellites are moving pretty fast with respect to earthbound receivers, so speed of light corrections are required (per special relativity), but that's not the whole story. The satellites orbit earth - which means that they are subject both to gravity fields and to almost constant acceleration to bend their motion into a near-circle. The two laboratories are also subject to gravity fields and to constant (but differing, since they are at different latitudes) acceleration from the rotation of the Earth. Per General Relativity theories, all of these effects warp space very slightly, changing the transit time of the radio signals. I expect that if the GPS system has to consider such effects at all, it uses a simplified model that gives it the desired accuracy without making the calculations too complex. <br /><br />So the scientists have to re-do the GPS calculations for better accuracy. They could easily have made a small mistake. But even without any errors, the final problem is that General Relativity is not one settled theory, but a short-hand term for a huge collection of competing hypotheses, which match the limited experimental results available (mainly astronomical observations), but do not give exactly the same results in every case. <br /><br />So the good news is not that FTL really happened, but that, assuming no one can find any calculation errors, they've finally found an experiment we can do on Earth that is sensitive enough to distinguish between some of the various hypotheses.markmnoreply@blogger.comtag:blogger.com,1999:blog-8515829.post-81998980659304092622011-11-19T04:07:57.109-08:002011-11-19T04:07:57.109-08:00FTL ships... one can dream. A bit better with that...FTL ships... one can dream. A bit better with that kind of news.Marjanoreply@blogger.comtag:blogger.com,1999:blog-8515829.post-65069715131025844822011-11-18T17:11:52.424-08:002011-11-18T17:11:52.424-08:00And the next revelation will be that Albert Einste...And the next revelation will be that Albert Einstein did NOT own a 1911 .45acp pistol.Rogernoreply@blogger.com