Re: A simple classical problem
- From: "Ahmed Ouahi, Architect" <ahmed.ouahi@xxxxxxxxx>
- Date: Wed, 26 Aug 2009 18:14:08 +0300
However, then, do a definitely take any convention along that matter as a
just as a problem to resolve...
Therefore, as anything would a just bolws up, by itself, along that matter
all along, a definitely as a matter a fact...
--
Ahmed Ouahi, Architect
Best Regards!
"Jonah Thomas" <jethomas5@xxxxxxxxx> kirjoitti
viestissä:20090826110045.5fce3387.jethomas5@xxxxxxxxxxxx
"Sue..." <suzysewnshow@xxxxxxxxxxxx> wrote:
Jonah Thomas <jethom...@xxxxxxxxx> wrote:
I have run into a relativity problem that ought to be simple, and I
am having trouble with it. I'd appreciate any help. My problem is in
understanding the classical view that relativity replaced.
It goes like this:
Two observers N and S (for north and south) with no relative motion
are 12 light-seconds apart. At t=-12, N sends a 12-second 100-hertz
maser signal to S, so there are 1200 cycles of that signal waiting
to be received.
At t=0, N sends a 5-second message to S, at 2000 hertz.
From N's perspective, his second signal reaches S at t=12 and ends
at t=17. And since N and S have synchronised their clocks as best
they can, this is also true from S's perspective.
How would this look to observers traveling at 0.5c going southward?
It looks to me like, without considering relativity, they would see
that at t=0 there are 1200 cycles of the first signal waiting for S
to receive them across 12 light-seconds. S will move at 0.5c
northward which blueshift that signal. S will reach the end of the
1200 cycles in 8 seconds.
At t=0, N's 5-second 2000 hertz signal starts, and it is redshifted.
When does S receive the beginning of the message? N began sending it
at t=0 and while the redshifted message moved toward S at c, S moved
toward it at 0.5c. So S should receive the beginning of the message
at t=8. The message went 8 lightseconds at speed c and S went 4
light-second at speed 0.5 c.
When does S receive the end of the message? The end of the message
leaves N at t=5, and its redshifted signal travels at c while S
travels toward it at 0.5 c. So the end of the message arrives at
t=13.
So, the time required to send the message was unchanged. Only the
1200 cycles before the message began were changed. What happened to
them?
The 0.5 c observers know that at t=0 there are 1200 cycles in
transit over the 12 light-seconds between N and S. N must have made
them by transmitting a 150 hertz signal for 8 seconds while he
traveled northward at 0.5 c.
What is different between the 5-second message which arrives early
but is otherwise unchanged, versus the earlier message which is
compressed?
Relativity doesn't suspend the Doppler effect.
It just allows for electrical charges that might locally approach the
speed of light.
I certainly wouldn't say that relativity would suspend the doppler
effect. I'm trying to understand where the classical model goes wrong.
It looks to me like when I have observers in different inertial frames
they calculate the length of messages as the same, but there is a sort
of gap at the beginning. Very strange.
.
- References:
- A simple classical problem
- From: Jonah Thomas
- Re: A simple classical problem
- From: Sue...
- Re: A simple classical problem
- From: Jonah Thomas
- A simple classical problem
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