Multiple Body Galaxy Simulations

[RainMan]

I've noticed that at the scale of galaxies, Universe Sandbox treats each galaxy as a black hole point source. The individual stars do not gravitationally affect each other.

I'd love for an option to be added for multiple-body star interactions. All the stars interacting gravitationally. I have another little program...quite basic.....that easily handles 2000 stars..

http://www.synthetic-reality.com/galaxy.htm

It's pretty basic, but shows that even 10,000 stars would not be beyond a PC's capability. It would be extremely cool if Universe Sandbox had an option for such a simulation when displaying galaxies.

[vh]

cool, maybe my computer isn't very fast, or universe sandbox does things differently, because when i have more than 500 or so objects on my screen it lagssssssssssssss baaadly

[atomic7732]

cool, maybe my computer isn't very fast, or universe sandbox does things differently, because when i have more than 500 or so objects on my screen it lagssssssssssssss baaadly

That's because of the labels and being 3d, as dust it probably works much better.

[vh]

well that's the whole point, right? the dust doesn't have mass
or am i missing something
i try to keep labels and trails off though

[SomeDude]

2 bodies

Each loop:

A calculates acceleration from B
B calculates acceleration from A

3 bodies

A calculates acceleration from B
A calculates acceleration from C
B calculates acceleration from A
B calculates acceleration from C
C caluclates acceleration from A
C calculates acceleration from B

4 bodies

A calculates acceleration from B
A C
A D
B A
B C
B D
C A
C B
C D
D A
D B
D C

5 bodies

A B
A C
A D
A E
B A
B C
B D
B E
C A
C B
C D
C E
D A
D B
D C
D E
E A
E B
E C
E D

"There must be gravitons", they say.

[vh]

so how do those programs do it. is the question.
or why can't universe sandbox do it (with an average computer)

[Darvince]

Graphics, most likely. Graphics cause almost all lag.

[vh]

This seems like a valid point too.
so which is it.

And if it's graphics i want an option for all planets to be represented by a dot instead of a 3d object (like dust is)

2 bodies

Each loop:

A calculates acceleration from B
B calculates acceleration from A

3 bodies

A calculates acceleration from B
A calculates acceleration from C
B calculates acceleration from A
B calculates acceleration from C
C caluclates acceleration from A
C calculates acceleration from B

4 bodies

A calculates acceleration from B
A C
A D
B A
B C
B D
C A
C B
C D
D A
D B
D C

5 bodies

A B
A C
A D
A E
B A
B C
B D
B E
C A
C B
C D
C E
D A
D B
D C
D E
E A
E B
E C
E D

"There must be gravitons", they say.

[Darvince]

Yeah, graphics are probably more than 99% of lag.