Re: OFFICIAL - GZG: Vacuum and zero/low gravity combat…?

On Sunday 07 Feb 2016 19:57:40 Jon Tuffley wrote:
> On 7 Feb 2016, at 19:23, Douglas Evans <devans@nebraska.edu> wrote:
> > Well, Sam, as embarrassed as I am to use the term, that's a paradigm
shift
> > for me.
> To quote a Dilbert strip: "Was that the sound of a paradigm shifting
without
> a clutch?"  ;-)
> > However, a slight change and
> > 
> >> without atmosphere or gravity Clouds of Chaff will
> >> [continue to rise] for awhile
> 
> I'm assuming that in zero/micro gravity then a chaff cloud would
continue to
> expand at whatever velocity it was chucked out in the first place, so
its
> area of effect would continue to get wider but sparser until it was
spread
> thinly enough to be ineffective. In low (Lunar) gravity and vacuum it
> would, as noted, simply fall to the ground.

Yes. In microgravity, density will drop with the cube of the
radius (double the radius, 8x the volume). The radius will expand
at a constant velocity due to the lack of anything to impede it.

However, the width of the cloud will also be increasing, so in
terms of blocking line of sight it's probably only dropping
with the square of the radius.

On another note, microgravity is a better term than zero gravity.
Gravity isn't actually zero anywhere near the Earth (even at 6,400km
altitude, it's still a quarter surface gravity). Microgravity/free fall
just means gravity is relatively constant and is the only force acting
on you. The crew of the ISS are all in a gravity field, falling towards
the Earth, they're just all falling at an almost (but not quite, hence
the term micro) identical acceleration as the station.

A chaff cloud released in orbit would still be influenced by gravity,
and if it was in orbit would gradually be pulled apart by gravity,
since gravitational effects on the 'lower' part will be stronger than
on the 'higher part'. This is unlikely to be important for wargaming
purposes though, unless the scenario calls for combat near a neutron
star or black hole.

-- 
Be seeing you,	      Games: http://www.glendale.org.uk/
Sam.		      Posts: http://www.google.com/+SamuelPenn