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Motion of randomly generated stars 
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#1
Sep508, 01:20 AM

P: 3

Hello, I am new to this forum  and impressed with the posts. I have recently developed an addiction to astrophysics. I wish to do the following:
 define a spherical "sandbox" with a radius of let's say 1, which I think of as "universe"  within that sphere I generate N number of points. Each point have the following attributes: 1) a coordinate: p(x, y, z) 2) a velocity: v(x, y, z) 3) a mass  define time as t Then, kickoff a program (that I'm hoping to write) which will represent all the points (stars) as I move to t+1, t+2 etc... Many points should collide, others turn into orbits, others will fly outside my "universe". I wish my model to be "accurate" according to gravity fields of each star. Can anyone share with me how I could go about achieve this goal ? (let's start with 3 stars) In advance, thank you. Regards, Dan. 


#2
Sep508, 01:22 AM

P: 2,258

n stars requires n^2 calculations. you'll run out of processing power rather quickly I'm afraid.



#3
Sep508, 01:33 AM

P: 3

Regards, Dan. 


#4
Sep908, 01:29 AM

P: 3

Motion of randomly generated stars
But... I'm not going abandon this easily. Nothing easy is worth doing. Since I don't know the first thing about celestial motion, I'm going back to the basics: Newton. I'll move onto GR later. First I building I'm building a gridable physics architecture. I have one question that may help me:  is there a distance limit for which gravitational contribution of other stars can be ignored (stars extremly far away) ?  if I have a cluster (I mean just a group) of stars, does all the members of the group behave in similar way, ie. can get away with applying a "pull" to the group rather consider each start individually? This will help me understand if I can grid clusters across the network. Regards, Dan. 


#5
Sep908, 11:47 AM

P: 145

Welcome to the forum, Dan. What you are planning to do falls in the general field of "NBody Simulations", googling for this might yield useful info.
Also this recent review paper http://arxiv.org/abs/0806.3950 might be interesting, section 3.2 Tree Codes seems to be related to what you wrote in #4 (grouping stars to clusters). A website from one of the authors of this paper, www.artcompsci.org contains (among other stuff related to scientific computation) some further info about NBody Simulations. 


#6
Sep908, 12:41 PM

P: 2,258

you might consider trying to form a spiral arm of a spiral galaxy. you could limit it to 2 dimensions and you might not even require ANY interaction between the stars. you could probably do a million stars quite easily. just put them in circular orbits of all different radius's around a central mass (but with all the dark matter I'm not sure they follow an inverse square law though) then somehow put a slight mass concentration in one area (not a concentration of stars) and see if their orbits shift into that area thereby creating an even greater mass concentration.
http://abyss.uoregon.edu/~js/ast122/lectures/lec26.html 


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