Universe Sandbox

Universe Sandbox Legacy => Universe Sandbox 2008 | Discussion => Topic started by: mattie on May 31, 2008, 02:49:19 PM

Title: playing with rings
Post by: mattie on May 31, 2008, 02:49:19 PM

if you open up the Saturn & moons scenario, then give Mimas about 0.5 moons worth of mass, then run the simulation at around 7 minutes per time step (you may have to delete the neighboring moons), you can see Mimas' gravity sculpting the rings, creating these concentric ringlets that expand as the simulation goes on. Anybody else notice this? I thought it was the coolest thing when I saw it.

Title: Re: playing with rings
Post by: Dan Dixon on June 01, 2008, 08:01:30 PM

I really wanted to make this work and followed your instructions but didn't get the concentric ringlets that you described. Setting Mimas at .5 moons (where 1 is the mass of Earth's moon) didn't seem to have much effect on the rings at all. Is the effect that you described subtle? Maybe you could post a screenshot.

To save a screenshot:
Bring up the control panel and click Screenshot at the bottom in the Capture group (no worries... the control panel won't be visible in the shot). The image is saved in My Documents\Universe Sandbox\Images.

Title: Re: playing with rings
Post by: mattie on June 03, 2008, 03:04:33 PM

Maybe my computer is weird. Here's a sequence of screenshots taken 2-3 seconds of real time (not simulation time) apart showing what I see:

(http://img292.imageshack.us/img292/8127/universesandbox20080603my6.png)

(http://img292.imageshack.us/img292/7461/universesandbox20080603ra9.png)

(http://img292.imageshack.us/img292/742/universesandbox20080603xt2.png)

(http://img292.imageshack.us/img292/4495/universesandbox20080603si3.png)

(http://img209.imageshack.us/img209/7776/universesandbox20080603ke8.png)

Title: Re: playing with rings
Post by: Dan Dixon on June 04, 2008, 01:37:43 PM

Awesome... Thanks for sharing the screenshots. That was very helpful.

I'm pretty sure that these concentric ringlets are caused by inaccuracies in the simulation and aren't what would really happen. Just adjusting the time step (the amount of time simulated per frame) creates them (load Saturn and then set the time step to 30 minutes). These ringlets form and then they seem to settle after a few moments. Changing the time step again causes them to reemerge.

You can get some fun results that are realistic by upping Mimas's mass to something larger like 1 earth.

Title: Re: playing with rings
Post by: mattie on June 05, 2008, 07:22:26 PM

theoretically, you should (eventually) get a gap corresponding to Cassini's Division, the 2:1 resonance point with Mimas. I'll have to run it overnight and see.

Title: Re: playing with rings
Post by: Raverend on June 18, 2008, 09:43:32 AM

I got that effect following the steps so yeah, it works.

Title: Re: playing with rings
Post by: mattie on June 20, 2008, 08:26:44 PM

even if the effect has no bearing in real life, having originated from computational errors, it's still interesting to watch