Welcome, Guest. Please Login.
Gravity Simulator
11/20/17 at 20:47:06
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
Asteroid May Hit Mars on January 30, 2008 (Read 18478 times)
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Asteroid May Hit Mars on January 30, 2008
12/23/07 at 21:40:52
 
I'll start a new thread for this asteroid since it a current event that is changing from day to day.  As mentioned in the "asteroids" thread, 2007 WD5 was reported as having a 1 in 75 chance of hitting Mars on January 30, 2008.  This was based on observations through December 21, 2007.  New observations are in.
 
It's predicted path is getting closer to Mars.  The media won't run another story until NASA makes another press release, but the updated numbers from some additional observations are now available.  December 23rd's data shows it is now predicted to pass 17631 km above the Martian surface, more than twice as close as the prediction made with December 21st's data.
 
This doesn't necessarily mean that the odds of 1 in 75 have improved.  I don't know what the error bar is on the new data.  Perhaps as well as the asteroid's trajectory moving closer to Mars, the error bar has shrunk enough to confidently exclude a Martian collision.  Or perhaps not.
 
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #1 - 12/23/07 at 23:14:10
 
In the above picture : is Earth at the right or the left ? (I guess to the left undecided)  
( don't know if the closest approach will be visible from Earth ) . I guess due to the light of Mars the approach won't be visible , even if the approach is on the good side .  
Herunder an animation of the approach as can be seen from Earth ( using the same data ) .  
One can see WD5 approaching to Mars from the right , almost in the plane of the ecliptic . After the closest approach the asteroid is a litle  deviated .  
I can't take out of this frames whether the asteroid passes in front or behind as the pictures refresh.
Back to top
 

2007WD5FromEarth.gif
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #2 - 12/23/07 at 23:46:50
 
In the top image (top down ecliptic view), Earth is on the left.  In the bottom image (within the ecliptic plane), Earth is on the right.  If this seems counter-intuitive, run the above .gsim.  When you're zoomed out enough to see the Earth, the two predictions share the same pixels.
 
Frank, you had mentioned earlier about the error bar for the SMA.  Where do you get that data?  It would be nice to apply it here.
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #3 - 12/23/07 at 23:53:13
 
Ok , makes sense . So it's possible the impact would not be visible from Earth .
 
You can obtain the errors from this site as a sigma-deviation .  
This deviation gets smaller and smaller as new obs come available.  
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007WD5&orb=1
Back to top
 
 
Email View Profile   IP Logged
APODman
Uploader





Posts: 35
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #4 - 12/26/07 at 05:39:49
 
I made some simulations of 2007WD5 in Solsyin this is the results ( all simulation are centered in Mars like reference body ):
 
The log of distance of 2007WD5_Mars in close approach:
 

 
MOID variation in 1000 years:
 

 
Eccentricity variation in 1000 years:
 

 
 
[ ]´s
Back to top
 
 

The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
Kepler
View Profile   IP Logged
APODman
Uploader





Posts: 35
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #5 - 12/26/07 at 05:44:58
 
2007WD5 have some ressonance with Mars ?
 

 
 
 
[ ]´s
Back to top
 
 

The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
Kepler
View Profile   IP Logged
APODman
Uploader





Posts: 35
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #6 - 12/26/07 at 06:29:23
 
Tony, a question:
 
I tried and tried but can´t simulate the encounter in Gravity Simulator. In the specific encounter day 2007WD5 and Mars are in opposite points in your orbits !
 
What is wrong ?
 
( I use the 2007WD5 data of NEODyS catalog and the "onlyplanets.gsim" - I retrograde the simulation until  27/10/2007, the epoch for NEODyS catalog, before create the 2007WD5 object with a stepsize os 1s )
 
Thanks !
 
[ ]´s
Back to top
 
 

The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
Kepler
View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #7 - 12/26/07 at 10:44:46
 
Quote from APODman on 12/26/07 at 06:29:23:
Tony, a question:

I tried and tried but can´t simulate the encounter in Gravity Simulator. In the specific encounter day 2007WD5 and Mars are in opposite points in your orbits !

What is wrong ?

( I use the 2007WD5 data of NEODyS catalog and the "onlyplanets.gsim" - I retrograde the simulation until  27/10/2007, the epoch for NEODyS catalog, before create the 2007WD5 object with a stepsize os 1s )

Thanks !

[ ]´s

 
"Full System.gsim" is better than "OnlyPlanets.gsim".  OnlyPlanets was designed to give a quick view of the solar system without too much emphasis on accuracy.  With Full System, simply delete the unwanted objects before you use it.  Are you using Gravity Simulator 2.0, or the Beta version?  If 2.0, I'd suggest updating (the link is a sticky at the top of this forum), as I've improved the code in the orbital elements to state vector conversions
 
The "asteroids" thread contains a simulation you can download of 2007 WD5 based on its December 21st solution  
 
If you want to create it yourself, there's 2 ways I would suggest:
Create by State Vectors:
Open FullSystem.gsim
Delete unwanted objects
Propogate the system at 1 second time step to your desired date and pause the simulation.
Use menu Objects > Create Objects to create 2007 WD5.  Just fill in the orbital elements with any dummy data.
Send the following e-mail to horizons@ssd.jpl.nasa.gov and put the word job in the subject line:
Code:
!$$SOF
EMAIL_ADDR=''
START_TIME = '2007-Apr-10 00:00:00'
STOP_TIME = '2007-Apr-10 00:00:01'
TABLE_TYPE = 'Vector'
REF_PLANE = 'Ecliptic'
CENTER = '@010'
COMMAND='2007 WD5'
!$$EOF

 


Change the Start Time to your desired time.  Change Stop Time to 1 second after Start Time.
When you get the return e-mail (usually less than 1 minute) search for the following data.  Highlight and copy the numbers I've boldfaced.  Be careful to not include any leading spaces, and becareful to not exclude any minus sign:
 
$$SOE 2454200.500000000 = A.D. 2007-Apr-10 00:00:00.0000 (CT)  
-5.392879637775785E+07 -3.387908707197315E+08 -3.296068904445007E+06  
1.824188513621929E+01 9.567253283120301E+00 -5.467607677044288E-01

1.144365187923066E+03 3.430720525370878E+08 -1.231012198996011E+01  
$$EOE  
 
Use menu Objects > Edit Objects and paste these 6 numbers into the x-position box.  It will parse them for you into the 6 position and velocity boxes.
 
 
Method 2:  using orbital elements
The link Frank gives in the 4th post in this thread gives you the orbital elements on April 10, 2007.  
Open FullSystem.gsim and delete the unwanted objects.
Propogate the system to April 10, 2007 at 00:00:00
use menu Objects > Create Objects
Enter the orbital elements.  Be sure to zero out all the +- boxes.
 
On your Moid diagram, shouldn't it come closer than 0.009 (about 1.3 million km) in 2008 as it is expected to pass much closer to Mars than this?
 
Thanks for those diagrams.  I'm going to use Gravity Simulator to make an eccentricity graph to compare to yours.  You and Frank will have to teach me how to compute MOID.
 
The resonance you display is a near resonance only.  Near resonances are not uncommon.  This asteroid travels nearly out to Jupiter, so it is likely that if it has a resonance it is with Jupiter, rather than with Mars.  But I've already tried this, and it does not seem to have a resonance with any of the planets.
 
 
 
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #8 - 12/26/07 at 11:04:16
 
Here's the plot of distance to Mars and Earth as I calculated it using the Picard Integrator.  
Zero time was at 01/02/2007 00:00.  
The minimum distance of 0.000146 AU's corresponds well to the distance caluclated by Neodys.  
MARS  0.0001594 .
Back to top
 

2007WD5dist.jpg
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #9 - 12/26/07 at 11:09:41
 
Quote : [/color]Method 2:  using orbital elements  
The link Frank gives in the 4th post in this thread gives you the orbital elements on April 10, 2007.    
Open FullSystem.gsim and delete the unwanted objects.  
Propogate the system to April 10, 2007 at 00:00:00  
use menu Objects > Create Objects  
Enter the orbital elements.  Be sure to zero out all the +- boxes[color=#cc9900].
[/color]End Quote .  
You can go further and click the botton "Ephermeris": then you get into a screen in which you can input the disered values . After some seconds you get the disired data .  
 
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #10 - 12/26/07 at 11:33:33
 
Note : after trying for some time to contact the above horizons site I finally got a return mail .  Smiley.  
I noticed that horizons does not reply to .hotmail adresses .
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #11 - 12/26/07 at 12:59:49
 
Concerning the calculation of the MOID between two elliptical orbits I used the following formulae :  
 
R=a·(1 - e*e)/(1 + e·cos(V))
'XH = R·[cos(O)·cos(V + w - O) - sin(O)·sin(V + w - O)·cos(i)]
'YH = R·[sin(O)·cos(V + w - O) + cos(O)·sin(V + w - O)·cos(i)]
'ZH = R·[sin(V + w - O)·sin(i)].  
 
V beeing the anomaly .
Then calculating the distance = sqrt (......) gives the distance at a given angle V1 and V2.  
Unfortunately there is not a closed formula to derive the MOID , so I help myself with a hill-climbing algorithm in order to get the minimum distance . I can provide the code if needed .  
                                   
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #12 - 12/26/07 at 14:23:49
 
Quote from frankuitaalst on 12/26/07 at 11:33:33:
Note : after trying for some time to contact the above horizons site I finally got a return mail .  Smiley.
I noticed that horizons does not reply to .hotmail adresses .  

 
Could it be in your bulk or junk mail box if hotmail thinks it is spam?
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #13 - 12/26/07 at 14:40:19
 
no , I checked , Horizons doesn't seem to reply to hotmail . I get a reply with another address . Funny .
Back to top
 
 
Email View Profile   IP Logged
APODman
Uploader





Posts: 35
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #14 - 12/28/07 at 10:30:58
 

 
I made a simulation of the Lyapounov time evolution of 2007WD5 in 100 years:
 

 
It's indicate that the orbit evolution of 2007WD5 can be previsible until after 6 years after the encounter. After this time the orbital elements data need to be revised.
 
The fast ascending line is previsible but interesting.
 
News about 2007WD5 in:
 
- http://neo.jpl.nasa.gov/news/news151.html
 
[ ]´s
Back to top
 
 

The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
Kepler
View Profile   IP Logged
APODman
Uploader





Posts: 35
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #15 - 12/28/07 at 10:39:31
 
Thanks by the help Tony,
 
I will try simulate again.
 
 
[ ]´s
Back to top
 
 

The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
Kepler
View Profile   IP Logged
Nexus
Uploader



Wazzup??

Posts: 21
Re: Asteroid May Hit Mars on January 30, 2008
Reply #16 - 12/28/07 at 13:54:14
 
I wonder if the Spirit or Opportunity robots on Mars will have a good view of the close encounter.
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
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #17 - 12/28/07 at 14:05:53
 
I'm afraid their resolution is not good enough . The size of the asteroid is estimated at about 50 meters across.  The object is to dim to detect for them .  
The MRO , orbiting Mars , has better resolution . It might catch the asteroid if its position is well .
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #18 - 12/28/07 at 14:14:35
 
A question for Tony : do you have any idea how to translate a given deviation of a , e...etc in a deviation of x,y,z , vx, vy, vz ?  
x, y, z may be simple , but how about vx,vy,vz ?  
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #19 - 12/28/07 at 19:37:02
 
Quote from frankuitaalst on 12/28/07 at 14:14:35:
A question for Tony : do you have any idea how to translate a given deviation of a , e...etc in a deviation of x,y,z , vx, vy, vz ?
x, y, z may be simple , but how about vx,vy,vz ?

The formulas are included in Gravity Simulator, so it's probably easiest to use Gravity Simulator rather than directly use the formulas with a calculator.
 
Let's say for example that your SMA is 1 AU with a 1 standard deviation of 0.1 AU
 
menu Objects > Create Objects
Create 1 object with an SMA of 1 AU, and whatever numbers you want for the other elements
Create 1 object with an SMA of 0.9 AU, and the same numbers you used for the 1st object
Create 1 object with an SMA of 1.1 AU, and the same numbers you used for the 1st object
 
Now use menu Objects > Edit Objects to view their x,y,z, vx, vy, vz.
 
Let me know what you get.  I've been wanting to populate the region of uncertainty from the elements in the link you earlier provided, but I haven't had time yet.
Back to top
 
 
Email View Profile WWW   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #20 - 12/28/07 at 19:42:24
 
NASA now sets the odds at 1 in 25 after finding pre-discovery photos.  But Horizons hasn't updated its numbers yet:
 
http://neo.jpl.nasa.gov/news/news153.html
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #21 - 12/29/07 at 01:33:41
 
It's weird : the observations of nov 8th appear in the list of Neodys.  
http://131.114.72.13/cgi-bin/neodys/neoibo?objects:2007WD5;obs;1;200
The Apache Point observatory made some observations at that time . Maybe they are already included in the predictions ?  
Back to top
 
 
Email View Profile   IP Logged
EDG
Ultimate Member
*****


oh, crumbs!!!

Posts: 611
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #22 - 12/29/07 at 01:55:06
 
If it misses, the asteroid orbit's surely going to be changed considerably, right? Could it swing back for another possible impact?
Back to top
 
 

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


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #23 - 12/29/07 at 09:15:44
 
As far as I can get out of the simulation provided by Tony the deflection of the asteroid is rather "small" ie. not a big bending . As the asteroid is not really attracted by Mars , but is rather "by accident " heading to Mars it will not stay in Mars' influence and continue its way . After some decades it will be again in the neighbourhood of Earth . See link herunder .  
http://131.114.72.13/cgi-bin/neodys/neoibo?objects:2007WD5;main
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #24 - 12/30/07 at 09:03:03
 
I made a simulation  to show what happens after the close approach to Mars .  
Light green is the present prediction . Dark green is one of the earlier predictions.  
The arrow indicates the point of closest approach to Mars.
Back to top
 

2007WD5ChangeAnim.gif
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #25 - 01/01/08 at 04:45:08
 
New observations are avalable .  
Seems that the distance to Mars has increased to 238e-6 AU.
Source : Neodys
Planet Date MJD Nominal Distance (AU)  
MARS  2008/01/30.51234  0.0002389  
 
For some reason the JPL site which generates the ephemeris is out now.
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #26 - 01/01/08 at 13:06:53
 
Quote from frankuitaalst on 01/01/08 at 04:45:08:
New observations are avalable .
Seems that the distance to Mars has increased to 238e-6 AU.
Source : Neodys
Planet Date MJD Nominal Distance (AU)
MARS  2008/01/30.51234  0.0002389

For some reason the JPL site which generates the ephemeris is out now.

It seems the JPL sites are down today.  Horizons still responds.  It does not indicate any new observations have been made.  But the site http://newton.dm.unipi.it/cgi-bin/neodys/neoibo?objects:2007WD5;obs;1;200 mentions 2 additional observations, one on the 29th, and a group of 3 on the 31st
I don't know how to interpret the Neodys table.  What does Stretching and Width mean?  Although the nominal path is further, what has happened to the error bars?
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #27 - 01/01/08 at 14:05:16
 
I don't know what they mean with streching and width . ( maybe it is the error along the path and the width of the path ??) . I have send an email to neodys for more information about this .  
My guess is that the error should be smaller as there is an extra observation ( sigma is reduced ) .  
It may be possible by now that Mars isn't anymore within the error ellipse.  
 
Note : as I was typing I saw the site is available again , but the new observations aren't yet in it .
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #28 - 01/01/08 at 14:15:02
 
The minimum distance is 2468 km, which is less than Mars' radius, so I don't think its out of the oval yet.  I wonder if minimum distance means 1 sigma?
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #29 - 01/02/08 at 14:23:14
 
The new observations of 2007WD5 of 31/12/2007 came in ...
Heres the picture of the latest simulation .  
The nominal distance to Mars has increased to 238E-6 AU , ie almost the double of the estimated distance on 23/12/07 . So the chances of a collosion become smaller . Mars was drawn manually in the following picture .
Back to top
 

2007WD5Rev0201.gif
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #30 - 01/02/08 at 15:32:25
 
Quote from frankuitaalst on 01/02/08 at 14:23:14:
The new observations of 2007WD5 of 31/12/2007 came in ...
Heres the picture of the latest simulation .
The nominal distance to Mars has increased to 238E-6 AU , ie almost the double of the estimated distance on 23/12/07 . So the chances of a collosion become smaller . Mars was drawn manually in the following picture .

I don't know if the further distance means less of a chance of a collision.  I don't know what the numbers are, but a predicted miss of 10,000 km +- 1,000,000 km is worse odds than 30,000 km +- 50,000 km.
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #31 - 01/03/08 at 05:15:44
 
New observations have narrowed the error-span . See the picture below .
http://neo.jpl.nasa.gov/2007wd5/wd5_unc2.gif
According to the article additional new observations may rule out a collision .
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #32 - 01/04/08 at 18:41:20
 
When I use the numbers from http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007WD5&orb=1 and propogate the asteroid forward from April 10 to January 30, I get a very close Mars passage that is barely above the surface.  But when I use the numbers from Horizons, it shows a passage just outside the orbit of Deimos, which seems consistent with what is being reported.
Back to top
 
 
Email View Profile WWW   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #33 - 01/05/08 at 03:33:04
 
That's funny . I asked both sites for the ephemeris on 01/12/2007 00:00 CT and became the following coordinates which are the same.  
 
 6.268510741251808E+07  1.613571956170959E+08  1.687564612249881E+05
  -2.667576811418542E+01  2.170517592459779E+01  1.368371085951920E+00
 
  6.268510741251808E+07  1.613571956170959E+08  1.687564612249881E+05
  -2.667576811418542E+01  2.170517592459779E+01  1.368371085951920E+00
Back to top
 
 
Email View Profile   IP Logged
Tony
YaBB Administrator
*****




Posts: 1051
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #34 - 01/05/08 at 14:51:57
 
Quote from frankuitaalst on 01/05/08 at 03:33:04:
That's funny . I asked both sites for the ephemeris on 01/12/2007 00:00 CT and became the following coordinates which are the same.

6.268510741251808E+07  1.613571956170959E+08  1.687564612249881E+05
 -2.667576811418542E+01  2.170517592459779E+01  1.368371085951920E+00

 6.268510741251808E+07  1.613571956170959E+08  1.687564612249881E+05
 -2.667576811418542E+01  2.170517592459779E+01  1.368371085951920E+00

 
I don't think you're using 2 independent methods here.  When you click "generate ephemeris" your transfered to Horizons.  I made one scenerio directly from the orbital elements, and the other from Horizons vectors.  There will always be a small difference as there's a little bit of gray area when converting from elements to vectors.  But the difference is usually in the low hundreds of kilometers, not 10s of thousands.  Hopefully soon there will be new observations.
Back to top
 
 
Email View Profile WWW   IP Logged
EDG
Ultimate Member
*****


oh, crumbs!!!

Posts: 611
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #35 - 01/10/08 at 08:31:06
 
http://www.cbc.ca/technology/story/2008/01/10/tech-mars.html
 
Looks like it's getting less likely that the asteroid will hit Mars now.
Back to top
 
 

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


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #36 - 01/12/08 at 05:24:57
 
Indeed , a collision seems to be ruled out now.  
hereunder is a nice animation from JPL showing the reduction of the uncertainty region as more observations became avialable.  
http://neo.jpl.nasa.gov/2007wd5/2007wd5d.gif
Back to top
 
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #37 - 01/12/08 at 13:53:33
 
It is now almost sure the asteroid will not hit Mars .  
What's the influence of the close encounter ?  
The picture hereunder shows the evolution of the Semi Major Axis and the kinetic Energy of the asteroid .  
Initial time is 01/02/07 .  
One can see the SMA drops significantly after the close encounter . Prior to the encounter to Mars there was a shear near Earth which raised the SMA .  
Interesting however is the fact that there is no jump in the kinetic energy at the time of close encounter to Mars . The influence in terms in kinetic energy becomes only clear if we look at the maximum energy which is slightly higher than before.
Back to top
fsscr000.jpg (attachment deleted)  
 
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #38 - 01/13/08 at 05:52:34
 
Another asteroid is coming to visit Earth : 2007TU24 is sheduled to come as close as 1.4 Lunar distances to Earth on Jan 29th .  
It is as big as Apophis .  
Contrary to 2007WD5 its orbit is very well defined for some months now .  
Herunder is an animated frame of the encounter , vieuwed from above . The asteroid comes from the right .  
As can be seen the moon itself is out of danger as the asteroid passes on top when the moon is at the bottom .  
Some prior observations of the asteroid are also visible . The latest observation of 01/01/2008 is represented as the "strong" line , as along this line the latest 4 observations come together .
Back to top
« Last Edit: 01/13/08 at 07:48:24 by frankuitaalst »  

2007TU24Above.gif
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #39 - 01/13/08 at 06:05:27
 
Another way to represent the close approach of 2007TU24 to Earth is to take a ride sitting on the asteroid and watch the Earth coming close in .....(looking in front in the direction of the direction of motion)  
The following animation was generated with a special writen code capable to visialize the planets coming in the angle of view of the asteroid .  
Angle of view is 90° here ( wide angle ) .  
Simulation starts about 200 days ago ....
One can see Mars coming in from the left , then Saturn , alos Venus , which turns his back and last the Earth/Moon couple also from the left.  The rotation of the moon around Earth is clearly visible .  
The last frames were taken in slow motion .  
As can be seen there is no very close approach to the Earth or the Moon  
Back to top
« Last Edit: 01/13/08 at 08:09:06 by frankuitaalst »  

2007TU2490degrees.gif
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #40 - 01/13/08 at 08:14:05
 
The picture herunder shows the variation of the Asteroids 2007TU24 orbit due to the close approach to Earth on 2008 Jan 29th .  
Its SMA is increaed by some 0.01 AU , putting it into a wider orbit around the sun.  
As is the case with 2007WD5 there is no significant change in Kinetic Energy .  
The exchange in kinetic energy is low as the asteroid passes Earth close at its aphelium ( point of biggest velocity ) .
Back to top
 

2007TU24.jpg
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #41 - 01/26/08 at 15:08:56
 
Heres a picture how the approach of 2007WD5 to Mars may look as seen from Earth .  
Picture was generated with a special feature and takes the ephemeris of 02/01/2008 into account .  
Mars is shown in the middle . The asteroid approaches from the right and seems to pass behind Mars .  
The lttle red dots ( hardly visible ) represent the asteroid , as the position was calculated and plotted every 3 minutes .
Back to top
 

Pic2007WD5small_dat_15.JPG
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #42 - 01/26/08 at 17:19:12
 
This picture of the approach seems more realistic...
I used an existing image of Mars to represent Mars . One can see two bodies approach Mars . They are the predictions of the asteroid 2007WD5 on 02/01/2008 and 23/12/2007.  
Vieuwpoint in this picture is Earth . The dots are exactly 3 minutes separated .  
Back to top
« Last Edit: 01/27/08 at 04:30:44 by frankuitaalst »  

Pic2007WD5smallReal.JPG
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #43 - 01/27/08 at 07:50:47
 
2007TU24 will miss Earth on 1.4 LD later this month  
This was sure already a couple of months ago .  
The animation herunder shows the passage of the asteroid viewed from the sun .
The frame was centered on Earth . One can see the Moon orbiting the Earth .  
The passage happens rather quickly :  At the moment the Moon is  at the left and seems to stop the asteroid approaches from the right ( at 4 'o clock ) and goes down diagonally .  
( Please scroll to the bottom to view the little red dots appear )  
The simulation was run for some more time as suddenly another blue body appears above Earth .  
This must be Venus .
Back to top
 

2007TU24AnimfromSun.gif
Email View Profile   IP Logged
frankuitaalst
Ultimate Member
*****


Great site

Posts: 1507
Gender: male
Re: Asteroid May Hit Mars on January 30, 2008
Reply #44 - 01/27/08 at 08:04:06
 
The picture herunder shows the same frame as above , but the frame wasn't refreshed for 0.6 years .  
One can see the orbit of the moon in this 0.6 years . The asteroid 2007TU24 appears as a red line.
Back to top
 

Pic2007TU240101_dat_2.JPG
Email View Profile   IP Logged
Pages: 1 
Send Topic Print