Narf the Mouse Posted April 21, 2011 Report Share Posted April 21, 2011 Re: Musings on Random Musings Also, define stationary. Quote Link to comment Share on other sites More sharing options...
Bazza Posted April 21, 2011 Report Share Posted April 21, 2011 Re: Musings on Random Musings And 'non-local' Space is non-local, right? Quote Link to comment Share on other sites More sharing options...
Cancer Posted April 21, 2011 Report Share Posted April 21, 2011 Re: Musings on Random Musings Frank and Earnest are in the same inertial frame in the problem you set up, and as long as they remain both in the same frame, the wavelength sent by F and received by E are the same, and the time for the light to go from one to the other is independent of whatever joint motion the two have relative to something else. Each of them will measure the same time interval no matter what. Relativistic effects start happening when you go between frames of reference, not within a single such frame. One of the fundamental assumptions in relativity is that the laws of physics operate the same way in all inertial frames. This assumption isn't due to Einstein; it's one that more or less everyone before and after Einstein requires of anything we call a scientific law. The oddities that everyone associates with relativity come when there are two different reference frames (moving at different constant velocities), and the apparent discrepancies between what one observer sees in the other guy's reference frame and what the other guy measures in his own reference frame. General relativistic effects come about when the observers are in accelerating frames, or equivalently frames in different levels in a gravitational well. ("Special" relativity is the special case of constant velocity differences between frames. "General" relativity is the more general case of frames that have non-constant velocity differences, i.e., are accelerating with respect to each other.) Quote Link to comment Share on other sites More sharing options...
Cancer Posted April 21, 2011 Report Share Posted April 21, 2011 Re: Musings on Random Musings Also' date=' define stationary. [/quote'] And 'non-local' Space is non-local, right? Both of these are non-trivial questions. Einstein addresses both directly in the early parts of his 1905 paper "One the Electrodynamics of Moving Bodies". I encourage you to read that for yourselves. The heavy math doesn't start until section 3, but every sentence in the early portions of that paper has important and well-considered meaning. Don't be put off by the first paragraph; you probably won't have the physics background to see what's going on. In Maxwell's equations (that describe all of electromagnetism, formulated in the late 19th Century) without the careful attention to relativity (which came 30 - 40 years later) you get a weird situation where if you move a magnet past an electrical conductor you supposedly get one thing, but if you move the conductor past the magnet you get another thing. If that were correct, then you'd have a way to tell absolutely who was moving and who wasn't. There is no equivalent trick in mechanics: when you do the math right, the same thing happens when viewed from two different frames of reference. That fundamental difference between mechanics and electrodynamics was very puzzling to physics. Even more puzzling was the null result when experiments were made to try to detect the absolute motion of the Earth. We know that the Earth moves in approximately a circle at about 30 km/second around the Sun, so its motion at one time of the year is 60 km/s different from its motion six months later. But a measurement that should have detected the consequences of these differences in Earth's velocity failed, and failed spectacularly, finding no such difference. The contradictions are resolved when you abandon the idea of absolute time and instead assume the speed of light is a constant in all frames of reference independent of the motion of the body that emits the light, AND define what you mean by "time" and "distance" precisely, AND work out the consequences of those assumptions and definitions. If you don't work them through, and cling to the intuition you've developed from an existence spent at low velocities and small accelerations and the seductive and intuitive idea of absolute time, then you won't understand and you will persist in thinking that there is a "correct" physical frame of reference in any particular problem, and you'll flunk out of a lot of physics courses at the sophomore level or higher. And if life were fair, any GPS-based device would stop functioning in your presence (and you'll be killed in your next plane trip), because if you don't include the relativistic terms in the GPS system you get errors in position of hundreds of meters (and some of those errors are vertical, not just horizontal). Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted April 21, 2011 Report Share Posted April 21, 2011 Re: Musings on Random Musings ... What the Prof said. Quote Link to comment Share on other sites More sharing options...
SteveZilla Posted April 22, 2011 Report Share Posted April 22, 2011 Re: Musings on Random Musings Both of these are non-trivial questions. Einstein addresses both directly in the early parts of his 1905 paper "One the Electrodynamics of Moving Bodies". I encourage you to read that for yourselves. The heavy math doesn't start until section 3, but every sentence in the early portions of that paper has important and well-considered meaning. Don't be put off by the first paragraph; you probably won't have the physics background to see what's going on. In Maxwell's equations (that describe all of electromagnetism, formulated in the late 19th Century) without the careful attention to relativity (which came 30 - 40 years later) you get a weird situation where if you move a magnet past an electrical conductor you supposedly get one thing, but if you move the conductor past the magnet you get another thing. If that were correct, then you'd have a way to tell absolutely who was moving and who wasn't. There is no equivalent trick in mechanics: when you do the math right, the same thing happens when viewed from two different frames of reference. That fundamental difference between mechanics and electrodynamics was very puzzling to physics. Even more puzzling was the null result when experiments were made to try to detect the absolute motion of the Earth. We know that the Earth moves in approximately a circle at about 30 km/second around the Sun, so its motion at one time of the year is 60 km/s different from its motion six months later. But a measurement that should have detected the consequences of these differences in Earth's velocity failed, and failed spectacularly, finding no such difference. The contradictions are resolved when you abandon the idea of absolute time and instead assume the speed of light is a constant in all frames of reference independent of the motion of the body that emits the light, AND define what you mean by "time" and "distance" precisely, AND work out the consequences of those assumptions and definitions. If you don't work them through, and cling to the intuition you've developed from an existence spent at low velocities and small accelerations and the seductive and intuitive idea of absolute time, then you won't understand and you will persist in thinking that there is a "correct" physical frame of reference in any particular problem, and you'll flunk out of a lot of physics courses at the sophomore level or higher. And if life were fair, any GPS-based device would stop functioning in your presence (and you'll be killed in your next plane trip), because if you don't include the relativistic terms in the GPS system you get errors in position of hundreds of meters (and some of those errors are vertical, not just horizontal). Ah, the Michaelson-Morley experiment. I've heard it described as one of the most important "null result" experiments in modern science. And there are some (imo nutjobs) on Youtube that deny the results. Quote Link to comment Share on other sites More sharing options...
Bazza Posted April 22, 2011 Report Share Posted April 22, 2011 Re: Musings on Random Musings Ah' date=' the Michaelson-Morley experiment. I've hard it described as one of the most important "null result" experiments in modern science. And there are some (imo nutjobs) on Youtube that deny the results. I'm more partial to Alain Aspect's famous experiment. Quote Link to comment Share on other sites More sharing options...
Narf the Mouse Posted April 22, 2011 Report Share Posted April 22, 2011 Re: Musings on Random Musings I'm more partial to Alain Aspect's famous experiment. Which is? Quote Link to comment Share on other sites More sharing options...
Bazza Posted April 22, 2011 Report Share Posted April 22, 2011 Re: Musings on Random Musings The actual experiment: http://en.wikipedia.org/wiki/Bell_test_experiments#Aspect.2C_1981-2 Stated more simply' date=' the experiment provides strong evidence that a quantum event at one location can affect an event at another location without any obvious mechanism for communication between the two locations. This has been called "spooky action at a distance" by Einstein (who doubted the physical reality of this effect). However, these experiments do not allow faster-than-light communication, as the events themselves appear to be inherently random.[/quote'] Quote Link to comment Share on other sites More sharing options...
Enforcer84 Posted April 23, 2011 Report Share Posted April 23, 2011 Re: Musings on Random Musings Which is? Not as famous as he'd hoped? Quote Link to comment Share on other sites More sharing options...
Lucius Posted April 23, 2011 Report Share Posted April 23, 2011 Re: Musings on Random Musings Wow...I can hear a neighbor's music, and it's actually pleasant. Lucius Alexander the palindromedary hopes it stays that way Quote Link to comment Share on other sites More sharing options...
Narf the Mouse Posted April 23, 2011 Report Share Posted April 23, 2011 Re: Musings on Random Musings Not as famous as he'd hoped? *Ba-dum-tink* Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted April 24, 2011 Report Share Posted April 24, 2011 Re: Musings on Random Musings Chromosome 2 in humans is a result of an end-to-end fusion of two ancestral chromosomes, leaving telomeres in the 'middle', and a second (inactive) centromere. As far as we know, is this arrangement unique to humans, or has this occurred to any other animal (or plant) on Earth as well? This is very common, I'd think. The number of chromosomes vary between species, and this would be one last step in the process of speciesation. Quote Link to comment Share on other sites More sharing options...
James Gillen Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Game Seven. Overtime. I'm not ordinarily much of a sports guy' date=' but wow.[/quote'] Game Seven of what? jg Quote Link to comment Share on other sites More sharing options...
Narf the Mouse Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Game Seven of what? jg The Tribble's Pie-Eating Contest. Quote Link to comment Share on other sites More sharing options...
Klytus Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings The Tribble's Pie-Eating Contest. Is that Tribbles eating pies or pies made from Tribbles? Quote Link to comment Share on other sites More sharing options...
SteveZilla Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Game Seven of what? jg ... of nine. Resistance is futile. Quote Link to comment Share on other sites More sharing options...
Narf the Mouse Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Is that Tribbles eating pies or pies made from Tribbles? I'm pretty sure I placed the apostrophe correctly so as to show the former. Quote Link to comment Share on other sites More sharing options...
Lawnmower Boy Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Game Seven of what? jg Actually, Game 7 of the first round of the National Hockey League championships between the Chicago Blackhawks and Vancouver Canucks, won last night in the fifth minute of overtime by the Canucks, on a goal from Alexandre Burrow at about 10:20 local, or four hours after my usual bedtime.* The city was under an all-enveloping cloud of gloom and silence for much of the last week as the Canucks gave up a 3 game advantage over the Blackhawks, a team that has emerged as its post-season nemesis over the last 3 years. It's lifted now, and the Canucks go on to play the Nashville Predators in the next round. I imagine Hermit will chime in soon about how excited Nashville is about spring hockey. *(I work early! And I'm totally not defensive about my lifestyle!) Quote Link to comment Share on other sites More sharing options...
death tribble Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Is that Tribbles eating pies or pies made from Tribbles? [THOR mode] Klytus, we would have words with thee ! [/THOR mode] Quote Link to comment Share on other sites More sharing options...
Enforcer84 Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Is that Tribbles eating pies or pies made from Tribbles? Gillian Anderson Quote Link to comment Share on other sites More sharing options...
Old Man Posted April 27, 2011 Report Share Posted April 27, 2011 Re: Musings on Random Musings Oh yes, Gillian Anderson's pie was really tasty. I never got tired of eating it, and boy did she want me to eat it a lot. I especially liked it with meringue. Quote Link to comment Share on other sites More sharing options...
Enforcer84 Posted April 28, 2011 Report Share Posted April 28, 2011 Re: Musings on Random Musings Oh yes, Gillian Anderson's pie was really tasty. I never got tired of eating it, and boy did she want me to eat it a lot. I especially liked it with meringue. I preferred it when she dribbled melted chocolate. Quote Link to comment Share on other sites More sharing options...
teh bunneh Posted April 28, 2011 Report Share Posted April 28, 2011 Re: Musings on Random Musings Yeah, Gillian's pie is always so moist and delicious. Chocolate, merangue, or just a drizzle of vanilla... I could spoon it up all day long. Quote Link to comment Share on other sites More sharing options...
Enforcer84 Posted April 28, 2011 Report Share Posted April 28, 2011 Re: Musings on Random Musings Totally, her peach is to die for. Quote Link to comment Share on other sites More sharing options...
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