Aurora 4x

VB6 Aurora => VB6 Mechanics => Topic started by: Kyle on September 06, 2018, 08:06:41 PM

Title: Comet movement
Post by: Kyle on September 06, 2018, 08:06:41 PM

Hi, hoping Steve can answer this, I don't see that it's been answered anywhere.

What's the formula for how far a comet travels in a given time period?
When it's < 1 AU from the sun, it's a nice constant speed.
But farther out, comets tend to move slower and slower the farther away they get, and it's not clear exactly how the distance is determined.

Thanks!!

Title: Re: Comet movement
Post by: Father Tim on September 06, 2018, 11:07:46 PM

Knowing Steve, it's probably the actual formulae for meteors/comets (Start here: http://mathscinotes.com/2011/07/speed-of-a-meteor/ (http://mathscinotes.com/2011/07/speed-of-a-meteor/)) modified ever-so-slightly for Aurora's 360-day year.

Title: Re: Comet movement
Post by: Steve Walmsley on September 07, 2018, 05:42:21 AM

Here is the code for C#

Code: [Select]

                    double AUTime = 0;
                    double OrbitTime = Math.Pow(Math.Pow(Comet.OrbitalDistance / 2, 3) / Comet.ParentStar.StarType.Mass, 0.5); // result in years

                    if (Comet.CurrentDistance > 1)
                    {
                        double CloserOrbitTime = Math.Pow(Math.Pow((Comet.CurrentDistance - 1) / 2, 3) / Comet.ParentStar.StarType.Mass, 0.5); // result in years

                        // time to move 1 AU at this distance in seconds
                        AUTime = ((OrbitTime - CloserOrbitTime) / 2) * (double) GlobalValues.SECONDSPERYEAR;
                    }
                    else
                        AUTime = 0.18 * (double) GlobalValues.SECONDSPERYEAR; // comet moves about 5.5 AU per year

                    double AUMoved = Timescale / AUTime;

Title: Re: Comet movement
Post by: Kyle on September 07, 2018, 07:26:04 AM

AWESOME!

Title: Re: Comet movement
Post by: Kyle on September 07, 2018, 08:19:31 AM

Would it make more sense for Comet.OrbitalDistance to be Comet.CurrentDistance in line 2?