Welcome, Guest. Please Login.
Gravity Simulator
11/22/17 at 17:57:07
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 ... 7 8 9 10 11 ... 15
Send Topic Print
Asteroids (Read 147033 times)
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Retrograde Asteroids Dance
Reply #120 - 03/30/08 at 11:06:45
 
Besides Dioretsa there are according to Wikipedia only a limited number of  asteroids in a retrograde orbit (6 in total ) .  
Pictured herunder are the orbits of 4 of them :  
"1999LE31", "2000 DG8","2002RP120" and "2005NP82" , the other beeing 200DG8 ( not simulated )  
Animation looks to the equatioral plane .  
Depicted are also the planets Jupiter and Saturn.  
One of the above asteroids has a period of more than 300 years and is not always on the frames.  
One frame covers 200 years . The whole sim was run for 15000 yeras.  
Contrary to the Dioretsa orbit the asteroids seem to have dynamically stable orbits , but with a lot of dynamics .!  
Looking from above all of them have a strong precession in the same sense as the other planets.
Back to top
 

ReverseAstSide15000y.gif
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroids
Reply #121 - 03/30/08 at 22:22:47
 
forget all about the science value.  That is one cool animation  Grin
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #122 - 04/01/08 at 05:36:27
 
The sixth known asteroid being in a retrograde orbit is known as 2004NN8.  
It has a very high eccentricity ( about 0.98 ) and has an orbit bringing it far beyond Pluto's orbit .  
Period is about 1000 years .  
As a result the asteroid seems to spend only 50 years out of the 1000 years inside the boundaries of our solar system .  
The animation shows the orbit of the asteroid over a period of 70.000 years .  
Visible also are Neptunes and Plutos orbit .
Back to top
 

2004NN8Asteroid.gif
Email View Profile   IP Logged
Nexus
Uploader



Wazzup??

Posts: 21
Re: Asteroids
Reply #123 - 04/17/08 at 01:04:13
 
Turns out the asteroid Apophis is more dangerous than we thought- a kid from Germany realized that there's a chance that when Apophis makes its close pass to Earth in 2029 it could hit a satellite. The impact could change Apophis's orbit so that it becomes more likely to strike Earth on its next close pass in 2036.
 
Below is a link to the story.
 
http://www.physorg.com/news127499715.html
Back to top
 
 

---
There was a thirsty science geek,
but now he is no more.
For what he thought was H2O
was H2SO4.
View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroids
Reply #124 - 04/17/08 at 02:05:06
 
Quote from Nexus on 04/17/08 at 01:04:13:
Turns out the asteroid Apophis is more dangerous than we thought- a kid from Germany realized that there's a chance that when Apophis makes its close pass to Earth in 2029 it could hit a satellite. The impact could change Apophis's orbit so that it becomes more likely to strike Earth on its next close pass in 2036.

Below is a link to the story.

http://www.physorg.com/news127499715.html

If someone were going to challenge NASA's math, don't you think they'd be a member of this forum?  Roll Eyes
 
This story is already de-bunked.  NASA and ESA deny having verified the boy's claim, and are sticking with the 1 in 45000 odds.  Apophis will not be near the equatorial plane when it crosses the geosychronous altitude, so the odds of it hitting a satellite are close to nill.  Even if it did hit one, the odds are slim it would alter its trajectory enough to significantly effect the odds.  Compared to a satellite, Apophis is extremely massive.  It's the size of a football stadium... not just a football field, but the whole stadium filled with dirt.  Satellites are less massive than cars.
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #125 - 04/17/08 at 04:24:34
 
If the German boys name is something like  Einstein or Mozart it might be interesting to go over his calculations ... Wink
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Asteroids 2008GD110 and 2008GP3
Reply #126 - 04/17/08 at 04:40:31
 
The recently discovered asteroid rocks 2008GP3 and 2008GD110 come as close as ca. 3 LD from Earth .  
The first one just flew by , the other will flyby in a couple of days .  
Both rocks ( diam . 20-70 m ) are animated herunder .  
Viewpoint is the sun .  
Edit :  I have to check if I didn't put the figure upside down here  
Back to top
 

2008GD110GP3-Anim.gif
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #127 - 04/17/08 at 06:32:34
 
Its quite uncommon that two asteroids flyby to Earth at such a small time interval .  
Heres an animation ( still in 2D  Smiley) of the orbits of 2008GD110 and 2008GP3 in rotating frame to Earth ( little dot at 11 o' clock ) .  
They don't seem to have a common origin.
Back to top
 

2008GD110GP3RotFrame.gif
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #128 - 04/18/08 at 08:12:59
 
Asteroid 2008CC71 was recently discovered and has a low Torino impact possibility .  
Running the simulation I noticed it has a near resonance to Earth of 4:7.  
In a rotating frame to Earth its orbit is as following .  
Sim spans a time period of -50 to 90 years .
Back to top
 

2008CC71AnimRot.gif
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroids
Reply #129 - 04/18/08 at 10:58:58
 
Nice find.  It seems like lots of asteroids are in some sort of resonance with one of the planets.  As long as this asteroid's resonance with Earth continues, it can not hit Earth.  I don't see Mars in your animation, but it seems like this asteroid is probably a Mars-crosser, which means that it one day be perturbed by Mars out of its resonance.
 
And it may not be in resonance at all.  Unless the errors are taken into account, and it can be demonstrated that all test asteroids within the error ellipse are in this resonance, it is difficult to conclude that this resonance exists.
 
I'm studying similar asteroids as part of an Independ Study class at my university.  Here's a list of some resonances I found:
 
http://orbitsimulator.com/astr699/ERS.html
 
But I have the same problem:  without accounting for the errors, I can't draw any of these conclusions.
Back to top
 
 
Email View Profile WWW   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroids
Reply #130 - 04/18/08 at 11:18:04
 
Here's a stand-alone program you might enjoy:
 
http://www.orbitsimulator.com/gravity/DataViewer.exe
 
It helps you spot resonances.  To use it, create a simulation that contains a bunch of asteroids.  Use the File > Output File to create an output file.  Choose the asteroids, and choose "a (semi-major axis", "e(eccentricity)", "i (inclination)", "w (periapsis)", "rho (ascending node)", and "P".  You must not choose any more or any less, or it won't work.
 
Now run the DataViewer.exe
Open your output file that you created with Gravity Simulator.
You can choose the various asteroids from the list.
If you change the number that says "10", this changes the largest values that will be displayed.  For example, at 10, it will display all resonances up to 10:9 or 9:10.  If you change it to 20, it will display all resonances up to 20:19 or 19:20.
 
B and F change your background and foreground color, so if you want to take screen shots and print your results, you won't use all your black toner if you switch to a white background.
 
Here's a screenshot:
http://www.orbitsimulator.com/gravity/images/resonanceviewer.GIF
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #131 - 04/18/08 at 23:40:46
 
Quote from Tony on 04/18/08 at 10:58:58:
Nice find.  It seems like lots of asteroids are in some sort of resonance with one of the planets.  As long as this asteroid's resonance with Earth continues, it can not hit Earth.  I don't see Mars in your animation, but it seems like this asteroid is probably a Mars-crosser, which means that it one day be perturbed by Mars out of its resonance.

And it may not be in resonance at all.  Unless the errors are taken into account, and it can be demonstrated that all test asteroids within the error ellipse are in this resonance, it is difficult to conclude that this resonance exists.

I'm studying similar asteroids as part of an Independ Study class at my university.  Here's a list of some resonances I found:

http://orbitsimulator.com/astr699/ERS.html

But I have the same problem:  without accounting for the errors, I can't draw any of these conclusions.

I took a look through the link above . Really impressive ! Seems as a lot of asteroids have very funny orbits !  
Concerning the 2008CC71 animation : this sim was run with the total planetary system , but the outer planets were set on "invisible". I also think Mars may disturb after some more time. Studying all the orbits within the error ellipse may take a lot of evaluation time.  
    
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #132 - 04/19/08 at 01:16:49
 
I ran the 2008CC71 sim again and put it on rotating frame on Mars . Mars appears as the brown line at 6 'o clock .  
The ast seems to avoid Mars for the next 70 years .  
Remarkable was the fact that the orbit in rotating frame was perfectly closed after ca. 25 years .
Back to top
 

Pic2008cc71_dat_70y.jpg
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroids
Reply #133 - 04/19/08 at 02:39:50
 
Quote from Tony on 04/18/08 at 11:18:04:
Here's a stand-alone program you might enjoy:

http://www.orbitsimulator.com/gravity/DataViewer.exe

It helps you spot resonances.  To use it, create a simulation that contains a bunch of asteroids.  Use the File > Output File to create an output file.  Choose the asteroids, and choose "a (semi-major axis", "e(eccentricity)", "i (inclination)", "w (periapsis)", "rho (ascending node)", and "P".  You must not choose any more or any less, or it won't work.

Now run the DataViewer.exe
Open your output file that you created with Gravity Simulator.
You can choose the various asteroids from the list.
If you change the number that says "10", this changes the largest values that will be displayed.  For example, at 10, it will display all resonances up to 10:9 or 9:10.  If you change it to 20, it will display all resonances up to 20:19 or 19:20.

B and F change your background and foreground color, so if you want to take screen shots and print your results, you won't use all your black toner if you switch to a white background.

Here's a screenshot:
http://www.orbitsimulator.com/gravity/images/resonanceviewer.GIF

Can you provide a .gsim file with a bunch of interesting asteroids ? I want to try the viewer above . Smiley
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroids
Reply #134 - 04/19/08 at 10:42:06
 
http://orbitsimulator.com/gravity/simulations/sma0.96_0.97.gsim
 
This file contains all known asteroids with a semi-major axis between 0.96 and 0.97 AU, so you should find some that jump into and out of 1:1 Earth resonances and perhaps some Venus resonances.  Just remember, it is very important that you choose only the orbital elements specified in the above post, as this program is expecting the output file to be in that exact format.
 
You can also use it with your existing simulations such as 2008CC71, although there is probably only 1 asteroid in that simulation.  But just make more simulations the same way, including more asteroids.
 
Somewhere on this forum is another stand-alone program for generating .gsim files directly from JPL Horizons data.  I'll post a newer version later that lets you make sims from the searchable asteroid database.  Then you can quickly make simulations with lots of asteroids.
Back to top
 
 
Email View Profile WWW   IP Logged
Pages: 1 ... 7 8 9 10 11 ... 15
Send Topic Print