[AR] Re: NASA test of quantum vacuum plasma thruster (was "Anyone heard of this?")
- From: Ian Woollard <ian.woollard@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sun, 3 Aug 2014 23:09:46 +0100
If you have photons leaving in significant numbers you will have at least
some thrust; but that's a conventional photon rocket. Photon rockets give
very small thrust and are highly inefficient; it turns out that almost all
the energy leaves with the photons and hardly any ends up accelerating the
vehicle. (It's due to the extreme mismatch between the exhaust speed and
vehicle speed, you always want the two to be about the same-ish relative to
the launch frame of reference aka inertial reference frame.)
Note that these thrusters have no photons leaving other than thermal ones
due to waste heat; they consist of sealed cavities filled with microwaves.
They claim that by quantum/relativistic/magic/somehow they will start
moving all by themselves.
I'll only really believe it if it floats up into the sky and yanks the
power cord out of the wall.
On 3 August 2014 09:23, Steen Eiler Jørgensen <steen@xxxxxxxxxxx> wrote:
> Den 03-08-2014 02:09, Ian Woollard skrev:
>
> > There's essentially no chance that a thruster can work where you turn
> > it on, feeding only electricity through it, and with nothing leaving
> > it; where you switch it off, and you're now moving faster. This is
> > what the emdrive is claimed to do.
>
> Please define "nothing". Photons (e.g.) have no mass, but nonzero momentum.
>
> /steen
>
>
>
--
-Ian Woollard
Other related posts: