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Anders Sandberg writes:
> I think you mix up things a bit. If I jump into my spaceship and blast > off from Earth (I have an urgent meeting at Aldebaran) with a constant > acceleration (as measured with an accelerometer onboard) you will see > my ship recede with a speed (as measured from Earth, for example by > observing the rate I pass regular milestones along my way) that > initially increases linearly with time, but gradually the increase > slows down and after a long while I appear to move near c. No FTL > there. > > Properly speaking the ship is in no inertial frame - it is defined as > a frame of reference experiencing no accelerations - but it is > possible to speak of instantaneous inertial frames for each > moment. However, in neither the ship frames or the Earth's frame is > anything seen moving beyond c.
Okay, I take your point.
I'm not actually talking about ftl in the strict interpretation of the
term.
I think the main point of disagreement is the time dilation effect and
whether it is possible to overcome it.
The fact that a ship can blast around the galaxy in within the crews lifetime is not much use to anyone else if they cannot communicate any information faster than a direct light signal.
You may like to look at Eric Baird's relativity pages
http://ourworld.compuserve.com/homepages/eric_baird/homepage.htm
which contain a lot of very interesting ideas about ftl travel and communication.
Jon Reeves
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Anders Sandberg writes:
> I think you mix up things a bit. If I jump into =
my spaceship and blast
> off from Earth (I have an urgent meeting at =
Aldebaran) with a constant
> acceleration (as measured with an accelerometer =
onboard) you will see
> my ship recede with a speed (as measured from =
Earth, for example by
> observing the rate I pass regular milestones =
along my way) that
> initially increases linearly with time, but =
gradually the increase
> slows down and after a long while I appear to =
move near c. No FTL
> there.
>
> Properly speaking the ship is in no inertial =
frame - it is defined as
> a frame of reference experiencing no =
accelerations - but it is
> possible to speak of instantaneous inertial =
frames for each
> moment. However, in neither the ship frames or =
the Earth's frame is
> anything seen moving beyond c.
Okay, I take your point.
I'm not actually talking about ftl in the strict =
interpretation of the term.
I think the main point of disagreement is the time =
dilation effect and whether it is possible to overcome it.
The fact that a ship can blast around the galaxy in =
within the crews lifetime is not much use to anyone else if they cannot =
communicate any information faster than a direct light =
signal.
You may like to look at Eric Baird's relativity =
pages
http://ourworld.compuserve.com/homepages/eric_baird/ho=
mepage.htm
which contain a lot of very interesting ideas about =
ftl travel and communication.
Jon Reeves