Welcome, Guest. Please Login.
Gravity Simulator
11/18/17 at 17:07:36
News: Registration for new users has been disabled to discourage spam. If you would like to join the forum please send me an email with your desired screen name to tony at gravitysimulator dot com.
Home Help Search Login


Pages: 1
Send Topic Print
Satellite formation lecture- can we do this in GS? (Read 3876 times)
EDG
Ultimate Member
*****


oh, crumbs!!!

Posts: 611
Gender: male
Satellite formation lecture- can we do this in GS?
03/09/11 at 10:01:23
 
http://bit.ly/faslZi - video of Robin Canup's lecture about satelite formation at this year's Lunar and Planetary Science conference (fast forward to about 13 minutes to get to the start, before that is largely admin stuff and student awards). There's an awesome 3D animated simulation of the impact believed to have formed the moon at around the 17 minute mark.  
 
Which makes me wonder... can we do this in GravSim? We can make individual particles, we can make discs/belts of them too... but doesn't that mean that there's the capacity to make spherical arrangements of particles too? If we could define a 'core' and 'mantle' of a planet as differently coloured solid shells of particles and then have them crash into eachother then we could do the same kind of thing as that simulation couldn't we?  
 
(it'd probably be slow as heck, but it'd be interesting to try!)
Back to top
 
 

(formerly known as Mal)
View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #1 - 03/10/11 at 07:44:52
 
Very intersting this presentation by Dr Robin Canup . Must have taken years of work !  
I don't think we can do such thing in GravSim .  
Physically particles cannot orbit on a sphere and create the illusion of a rotating sphere .  
But we can simulate a 2-dimensional analogue , meaning a ring collision .  
Here's my try you can play with :  
In blue the Earth , half of its mass in the core . The mantle has 500 particles in order to get 1 full earth .  
The impactor has 0.1 Me in the core and has 200 particles , so we get 0.2 Me.  
I ran the sim at 1 sec timestep .
Back to top
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #2 - 03/10/11 at 09:18:35
 
Possible setups are of course countless .  
The animation here shows the outcome of above simulation
Back to top
 

Collision_Sim_Animation.gif
Email View Profile   IP Logged
EDG
Ultimate Member
*****


oh, crumbs!!!

Posts: 611
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #3 - 03/11/11 at 07:32:41
 
Wow, that's pretty cool! (probably more like a galaxy collision I guess?)
 
Could you set up a polar ring at at the same distance at 90 degrees to the equatorial ones in both cases? Then at least we might see some 3D elements to the collision?
 
We may not be able to do a full 3D sphere collision *now*, but maybe Tony could tweak the program... Wink
Back to top
 
 

(formerly known as Mal)
View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #4 - 03/13/11 at 12:18:04
 
I ran into problems when adding a polar ring . The system got me an overflow . Maybe the number of bodies in GravSim is limited to 1000 ?
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #5 - 03/13/11 at 12:26:57
 
The max allowed objects is 10,000.  But trouble seems to pop up anytime you exceed about 500 objects.  You will get an overflow if more than 100 objects collide in a single iteration.
Back to top
 
 
Email View Profile WWW   IP Logged
EDG
Ultimate Member
*****


oh, crumbs!!!

Posts: 611
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #6 - 03/13/11 at 22:02:36
 
I guess that doesn't bode well for having spherical groupings of objects...  
 
Also, is it me or are the smaller particles not colliding with the central object at its surface radius? Shouldn't they be disappearing when they hit that, not going through it?
Back to top
 
 

(formerly known as Mal)
View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #7 - 03/15/11 at 10:21:50
 
I think I can give a second shot here , unless Tony beats me in time Smiley  
Most of the particles are absorbes , some indeed seem to pass over Earth , maybe some indeed are inclined . Have to take a look .
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Satellite formation lecture- can we do this in
Reply #8 - 03/17/11 at 10:40:04
 
Some help needed :  
 
I created the following sim :  
* started with 2 bodies , Earth (1 Earth mass ) and Moon ( 0.1 Earth mass )  
* tuned the orbital parameters so that the come very close  
* ran the sim backwards in order to have some safe distance between the two bodies .  
* then changed their masses to 0.5 M and 0.05 M respectively , being the cores  
* then added 300 bodies to each , with diameter 50 km and Sma 3500,6000 for Earth and Sma 1250,2000 for the moon , and having masses 0,00165 and 0,000165 Me , so that each envellope has a mass of 0.5 Me and 0.05 Me for the moon  
* the result should be 2 bodies surrounded by a dense cloud , being their envellopes .  
 
To my surprise , when running the sim al of the 300 + 300 bodies got a mass 0 instead of the inputted masses  
( visible through the "Edit" menu ) .  
Also the diameters ( set at 50 km +/- 0 ) seem to vary , ie not being equal to 50 km  
 
I'm wondering if this odd behaviour is due to the "." , "," issue ?  
Can somebody repeat some part of the setup ?  
Back to top
 
Email View Profile   IP Logged
Pages: 1
Send Topic Print