Re: Relativistic CMB

From: Rob Dekker (rob_at_verific.com)
Date: 01/27/05 

Date: Thu, 27 Jan 2005 23:32:15 GMT

"Dirk Van de moortel" <dirkvandemoortel@ThankS-NO-SperM.hotmail.com> wrote in message news:Ev3Kd.6717$tg6.6000@news.cpqcorp.net...
[...]

> > > Something that I never understood from the twin paradox comes to mind again :
> > >
> > > If the travelling brother continuously runs his engines to create 1g accelleration,
> > > and he gently turns his ship around at 1/4 and at 3/4 of the trip, then
> > > both brothers would have felt 1g gravity at all times.
> >
> > Err, if he turns his ship around, however gently, he feels
> > more than 1g.
>
> Suppose you are coasting at some constant speed
> w.r.t. some inertial frame. Then you fire your trusters
> in the direction of your movement. From then on you
> will feel a constant acceleration of 1g in the opposite
> direction. In the original frame o.t.o.h. you will be
> seen to decelerate, gently turn around and then
> accelerate again, while you have been feeling 1g
> gravity all the time. I think that's what Rob has in
> mind.

Yes. But I think that Bjoern also understood that.

> Of course this does not happen at 1/4 and 3/4
> of the trip, but at 1/2.

Well, if he starts with speed 0 w.r.t. Earth, and
wants to get back to Earth, and land with speed 0 w.r.t.
Earth, then he must make two turns : one at 1/4 and
one at 3/4 of the trip.

The maximum speed that he obtains will depend on the
time he plans for the trip.

>
> Dirk Vdm
>
>

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