Useful equations?

[Schtoobs]

I bought this simulator because I am doing a physics degree and thought it might help inspire me to keep going and maybe even help with the astrophysics side of things.  Anyway, I am struggling to build anything. I saw people on here talking about binary systems and thought I'd have a go.  But, unsurprisingly, the two suns just crash straight into each other.  I figure that if they are equal in mass and, starting parallel but moving in opposite perpendicular directions, they would curl around towards one another and then orbit each other.  This might be totally wrong of course (let me know). Too slow and they crash into each other, too fast and they don't curl around enough.  With my limited knowledge I realise that if their mass is constant, then their distance apart and velocity must be specific values, dependant on each other. 

Getting to my point (finally), wouldn't it be nice if there was some kind of equation list (with layman explanations) and an astrophysics specific calculator built in, so people could work things out? I think this could be a great learning tool! Not to mention the satisfaction of calculating the math and then being able to test it to see if you were right.  I imagine this is part of the enjoyment for some of you pro's Might make it more accessible for physics noobs like me.

Most likely everything I'm trying to do could be easily done with the tools given, but I'm finding it hard to figure them out.

Hi, btw, I am Schtoobs.  (sorry, bad manners)

[Dan Dixon]

Be sure to check out this thread. It should help you figure out how to create a binary star system:
http://universesandbox.com/forum/index.php/topic,3432.0.html

[Schtoobs]

Wow that was fast! Response velocity = speed of light   This post was supposed to be more about the idea of a list of equations, explanations and a way of doing the calculations in the simulator, but the way I wrote it was all wrong.  Probably not a good idea anyway, still I might have a good one one day 

Great app by the way, it seems to me the success you are having is thoroughly deserved.

[Joshimitsu91]

Yeah, the link that Dan posted helped me alot, you should check it out.

Providing you give enough of a starting speed (not too high), you should be able to get a decent orbit, although it may be elliptical. Try pausing and manually setting the coordinates and velocities if you haven't already, means you can easily play around and see what sort of velocities you would need.

I suppose you could work out the velocities you would need to get circular orbits by yourself if you wanted to. You'd have to balance the equation for gravitational force with the centripetal (might be the wrong one...) ficticious force and get v from there. Thats how you do it for a planet orbiting a Sun, but i suppose two suns in a binary orbit will make the calculations abit more complex? I'm not entirely sure.

I'm also doing a physics degree (2nd year), but i only did astronomy in my first year, so i'm not 100% sure how you could calculate the speeds needed. Where are you studying?

Josh

EDIT: Also, i think Dan said in another post that using the euler method can result in unrealistic orbits in some situations, so it may be worth switching to RK4 in the options (if you haven't already / if your PC can handle it).

[Dan Dixon]

This post was supposed to be more about the idea of a list of equations, explanations and a way of doing the calculations in the simulator, but the way I wrote it was all wrong.  Probably not a good idea anyway, still I might have a good one one day 

Not a bad idea at all. If someone comes up with the content, I'd be happy to add it as a page inside the program's web engine.