Speed of Light: A universal Constant?
in [Relativity]
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From: Henri Wilson on 22 Mar 2005 03:47 On Tue, 22 Mar 2005 01:22:15 GMT, Sam Wormley <swormley1(a)mchsi.com> wrote: >Henri Wilson wrote: > >> You are right. Light speed is source and observer dependent. >> > > Speed of light is empirically independent of the relative velocity > between source and observer. That is a postulate. It has never been supported by any evidence. HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong.
From: Alex on 22 Mar 2005 04:11 A clock second is always seen by an observer who is also in the frame of the clock to be one second long. The difference occurs, as you say, from one frame to another. According to four dimensionalism, when an observer moves at high speed relative to another observer he observes time measurements in the other frame as measurements of a combination of time and space, it is like the time axis of the other observer leans over in the direction of travel. See: http://en.wikipedia.org/wiki/Special_relativity_for_beginners Best Wishes Alex Green
From: Alex on 22 Mar 2005 04:40 The problem with this approach is that modern physics does not hold that the speed of light rays is constant in all media. It maintains that there is a universal constant called the 'speed of light'. See: http://en.wikipedia.org/wiki/Special_relativity_for_beginners If you are uncomfortable with the four dimensional approach to physics please explain how three dimensionalism could operate. As early as Parmenides and Zeno people realised that everyday occurrences such as motion only made sense in the context of things being laid out along a time axis. In three dimensions there is nothing to distinguish a moving arrow from a stationary arrow and in the stadium paradox we end up with 'half the time' being equal to a 'whole time'. In a 3D world nothing happens because we are at a durationless instant. Best Wishes Alex Green
From: kenseto on 22 Mar 2005 08:21 "Mark Fergerson" <nunya(a)biz.ness> wrote in message news:LaF%d.149857$FM3.86220(a)fed1read02... > kenseto wrote: > > SR says that the speed of light is a universal constant. > > > > Questions: > > Why a clock second used to define the speed of light is not an interval of > > universal time?? > > Nobody else even uses the term "universal time". So what?? Everybody knows what the term universal time means. Ken Seto
From: kenseto on 22 Mar 2005 08:26
"David Cross" <nospam(a)spammenot.com> wrote in message news:Isk%d.742566$8l.242409(a)pd7tw1no... > "kenseto" <kenseto(a)erinet.com> wrote in message > news:xGi%d.1948$cC6.590(a)fe2.columbus.rr.com... > > SR says that the speed of light is a universal constant. > > > > Questions: > > Why a clock second used to define the speed of light is not an interval of > > universal time?? > > Why does SR say that a clock second in one frame does not correspond to a > > clock second in another frame when the speed of light is a universal > > constant?? > > Because the invariance of the speed of light requires that space and time not > be invariant. So even if I'm moving at 0.99*c, I will still measure the speed > of light from a pulse you send to me as being 2.998 * 10^8 meters per second. > It will certainly be Doppler shifted, though. Doppler shifting is due to light arriving at the observer at different speeds. > > I fail to see the problem over which you apparently are tearing your hair out. That's becasue you failed to recognize that Doppler shift is due to varying speed of light. Ken Seto |