Well last night I did an entire rewrite of the main physics code after doing
some reasearch at various places on the net. Also I added in the Z vector to
allow it to work in 3 dimensions.

All of the particles are given random positions and vectors at the start
(apart from the big one in the centre which I set up manually). The camera
is set to follow the big one and so is the light source that is why you can
see no gravitational effects on it. I was quite pleased to see it settle
into a nice little solar system.

My next plan is to set up a Sun/Earth/Moon system (just to see if I can)

Any ideas, comments etc....

Dave

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Attachments:
Download 'particle.avi.dat' (376 KB)

"Dave Brickell" <d.b### [at] ntlworldnospamcom> wrote :
>
> I was quite pleased to see it settle
> into a nice little solar system.
>
> My next plan is to set up a Sun/Earth/Moon system (just to see if I can)
>
> Any ideas, comments etc....

    Actually it doesn't seem to be settling down at all... to me. I suspect
that you might still experience at least two of your three planets
evaporating out of the system.

    I have been thinking lately about solar systems, on a non-mathematical
level, and I can't see any solar system forming out of anything but a
uniform but swirling cloud of dust. It can't even be rocks.

    Dust in orbits that are not quite stable will impact dust that -is- in
stable orbits and gradually accrete an object that is large enough to
attract more dust. If there are -any- significant bodies that are not in
stable orbits, if they impact the objects in the stable orbits, they will
throw them off.

    Everything that is in the area around the stable orbit has to be
traveling at nearly the same speeds, meaning no eccentric orbits, and has to
be of minor mass.

    So, to make a solar system, start with stable orbits (as stable as
orbits ever get) or start with a dust cloud.

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Probably decreasing the time step size will help getting the thing stable.
What kind of algorithm are you using? What happens to the mass of those
disappearing particles? Maybe adding their masses to the mass of the fixed
object will increase stability too,

--
Apache
http://geitenkaas.dns2go.com/experiments/
apa### [at] yahoocom

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Apache <apa### [at] yahoocom> wrote in message
news:3c938535$1@news.povray.org...
> Probably decreasing the time step size will help getting the thing stable.
> What kind of algorithm are you using? What happens to the mass of those
> disappearing particles? Maybe adding their masses to the mass of the fixed
> object will increase stability too,

That is exactly what the system does. The object in the middle is not fixed,
its just that the camera and light source follow that one fat particle
around thus giving the impression that it is fixed.

Dave

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> That is exactly what the system does. The object in the middle is not fixed,
> its just that the camera and light source follow that one fat particle
> around thus giving the impression that it is fixed.

Maybe better to have a fixed grid (or a checkerboard ;) as the background ?

... so we can follow a bit the motion of the cam ...

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Jan Walzer <jan### [at] lzernet> wrote in message
news:3c93b593$1@news.povray.org...
> > That is exactly what the system does. The object in the middle is not
fixed,
> > its just that the camera and light source follow that one fat particle
> > around thus giving the impression that it is fixed.
>
> Maybe better to have a fixed grid (or a checkerboard ;) as the background
?
>
> ... so we can follow a bit the motion of the cam ...


Good Idea :)

Dave

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could do with a little more light

-- 
Rick

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