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Asteroid May Hit Mars on January 30, 2008 (Read 18512 times)
Tony
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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.
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frankuitaalst
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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 .
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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.
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frankuitaalst
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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
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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.
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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.
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frankuitaalst
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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
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frankuitaalst
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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.
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fsscr000.jpg (attachment deleted)  
 
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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 .
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« Last Edit: 01/13/08 at 07:48:24 by frankuitaalst »  

2007TU24Above.gif
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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  
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« Last Edit: 01/13/08 at 08:09:06 by frankuitaalst »  

2007TU2490degrees.gif
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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 ) .
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2007TU24.jpg
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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 .
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Pic2007WD5small_dat_15.JPG
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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 .  
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« Last Edit: 01/27/08 at 04:30:44 by frankuitaalst »  

Pic2007WD5smallReal.JPG
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frankuitaalst
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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 .
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2007TU24AnimfromSun.gif
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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.
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Pic2007TU240101_dat_2.JPG
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