Harry-- If the space ship is between galaxies looking at star will be of no help. The will are be observed as receding from you given the expansion of space. And what’s more, how does an accelerometer work that must contend with an increasing space volume as one is trying to accelerate? If there is a measurable gravitational field you would conclude you are it would be getting smaller with time, assuming time is not expanding with the space. Unless your EM drive would go faster than the expansion of space you would be lost for ever. We are lucky that space within a galaxy does not expand like space between galaxies as we know happens according to the Big Bang theory. Anybody traveling between galaxies should stay away from the boundary that separates him from a zone of expansion of space that is more than his ship can handle.
Bob Cook Sent: Thursday, March 17, 2016 3:42 PM To: vortex-l@eskimo.com Subject: Re: EXTERNAL: Re: [Vo]:Re: EM Drive(s) People riding in a Emdrive spaceship could compare their motion to background stars before and after the acceleration to determine how much their speed has changed. Or they could use an onboard accelerometer to compute their new velocity from the prior period of acceleration. As you pointed out all the tests todate use an external energy supply so until the drive operates with an onboard energy supply I think it is also plausible to say it may only work with an external energy supply. The external energy supply might create acceleration by *increasing* the mass of the drive instead of reducing the mass of the drive. Figuratively speaking the drive would "suck". On Mar 17, 2016 12:56 PM, "David Roberson" <dlrober...@aol.com> wrote: If nothing is remaining of the ship then it can not have a finite value of kinetic energy relative to any observer. Remember this was an example of carrying the process to the extreme. That technique can point out problems in many visual concepts. If you apply the same technique to a normal rocket then all of the original energy and mass can be accounted for in the exhaust. Nothing vanishes. Dave -----Original Message----- From: H LV <hveeder...@gmail.com> To: vortex-l <vortex-l@eskimo.com> Sent: Thu, Mar 17, 2016 12:36 pm Subject: Re: EXTERNAL: Re: [Vo]:Re: EM Drive(s) Relative to its initial state it has gained kinetic energy. If the Emdrive needs and external source of energy then it may work by preserving CoE but by violating CoM. Harry On Thu, Mar 17, 2016 at 11:58 AM, David Roberson <dlrober...@aol.com> wrote: > Of course the EM drive ship that remains in this extreme case(actually > nothing at all if zero exhaust is present) is at rest which means it has > zero kinetic energy relative to itself. Again, this is not a problem for a > normal rocket that spits out reaction mass. In that case all the missing > mass and energy can be located by analyzing the exhaust stream. This is > true regardless of what reference frame you choose. A normal rocket obeys > CoE and CoM whereas the EM Drive ship does not. > > If it can be shown that the EM drive emits its mass in the form of radiation > out the exhaust then all is well. But thus far it is suggested that nothing > is performing that function. > > Dave > > -----Original Message----- > From: mixent <mix...@bigpond.com> > To: vortex-l <vortex-l@eskimo.com> > Sent: Wed, Mar 16, 2016 9:29 pm > Subject: Re: EXTERNAL: Re: [Vo]:Re: EM Drive(s) > > In reply to David Roberson's message of Tue, 15 Mar 2016 11:19:13 -0400: > Hi, > [snip] >>When might somehow be important but if you take the process to the extreme >> you get a result that doesn't make any sense. For example, if the spaceship >> continues to use up its mass in a constant acceleration process that >> requires power and thus energy to be expended for the drive, then eventually >> there will be no mass left at all. All of the original mass is lost if this >> takes place. That does not make sense. > > The process stops, when all the mass has been converted into kinetic energy. > > The only thing I know of that only has kinetic energy and no mass is EM > radiation. > > Regards, > > Robin van Spaandonk > > http://rvanspaa.freehostia.com/project.html >
