Asteroid may hit Mars, 1 in 75 chance. Tunguska sized

[MeteorWayne]

The uncertinty is in the position of the asteroid. It's very small, and hard to observe right now. After the moon gets out of the way, more precise measurements will be possible. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[billslugg]

Brad<br />You could use the Univ of AZ impact calculator to see if it breaks up in the Earth's upper atmosphere. If that altitude has an air density less than what Mars has at the ground level, then it would break up. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[3488]

Sorry silylene,<br /><br />Duh, I linked to wrong article. New one is here.<br /><br />Hi Brad, to follow up billslugg's idea,<br /><br />The Martian atmosphere @ the Datum Line (6.1 millibars) is the same as Earth's is<br />@ 30 KM / 19 miles above sea level.<br /><br />@ the summit of Olympus Mons, it is barely one half of one millibar or 1/2000th the Earth's<br />surface air density. Just to give a range of martian atmospheric densities.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[silylene old]

Andrew, thanks for the link. It seems as if the most likely intersection of the asteroid's orbit and Mars's orbit is a few Mars diameters off the surface (no collision). But the error bar is still very substantial. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[dragon04]

<font color="yellow">I have very severe doubts about terraforming Mars, but this impact with 2007 WD5 will show us much.</font><br /><br />The comment I mad on terraforming was more idle speculation than anything. <img src="/images/icons/smile.gif" /><br /><br />However, a Chixhilub-sized Impactor would be more than a little fascinating to behold, to say the least.<br /><br />The sheer volume of liberated CO2 and water vapor in an instant would make for some very cool science for decades and centuries to come.<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[brellis]

What kind of force would it take to alter the asteroid's trajectory enough to guarantee impact? <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>

 

[MeteorWayne]

The error bars are large enough an impact can't be guaranteed at this time. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[MeteorWayne]

No we don't; that's why the error bars are so large.<br /><br />Some prediscovery observations allowed the orbit to be refined to increase the odds of a hit to 3.9%, but ironically moved the center of the likely path away from Mars.<br /><br />Once the asteroid moves away from the moon in our sky, the accuracy of the orbit will increase, and the error ellipse will decrease in size rapidly.<br /><br />In a week or so, the eventual path should become much clearer. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[nuaetius]

<blockquote><font class="small">In reply to:</font><hr /><p>Recent observations have increased the likelihood of a Mars impact to 1 in 25. The odds may <br />yet be reduced further as uncertainties in exact trajectory are being ironed out. <br /><br />Odds of impact have decreased to 1 in 25 or 4%. <br /><br />Andrew Brown.<p><hr /></p></p></blockquote><br /><br />Something I have not send is if there is a 1/25 chance of impact, what is the possibility of capture in Mars gravity but no immediate impact. I am not saying this thing is going to become Phobos’s baby brother but what are the changes it will get locked up in a huge orbit for a few months and then fall into the gravity well… less or more than 1/25?<br />

 

[keermalec]

Almost no chance of getting caught in the gravity well. If it came in with higher than escape velocity then it will leave with higher than escape velocity. Only thing that can slow it dow is an impact or... a grazing of the atmosphere. <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[dragon04]

<font color="yellow">What kind of force would it take to alter the asteroid's trajectory enough to guarantee impact?</font><br /><br />That's a question I'm unequipped to answer. But considering Jupiter's gravitic influence out that way, the short answer?<br /><br />LOTS. And LOTS. <img src="/images/icons/wink.gif" /> Certainly beyond our current technical capabilities for a long time to come unless some serendipitous discovery comes along.<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[spacy600]

What would happen if it hit one of the two moons?<br /><br />Can it knock one of the moons into Mars?<br /><br />Kinda like a billiard table.<br /><br />Thanks

 

[3488]

Probably not. 2007 WD5 is tiny, even compared to Deimos the smaller of the Martian moons.<br /><br />2007 WD5 diameter: Approx 55 metres.<br /><br />Deimos dimensions: 15 km x 12.2 km x 11 km.<br /><br />Phobos is very much larger. Dimensions: 27 km x 21.6 km x 18.8 km.<br /><br />So I would doubt it very much, though 2007 WD5 would leave a beautiful crater on <br />either.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[MeteorWayne]

I know some of this is old info, but here is the NEO news release:<br /><br /><br />NEO News (12/28/07) Odds of Mars Impact Increase<br /><br />Date Released: Friday, December 28, 2007<br />Source: Jet Propulsion Laboratory<br /><br />Updated Dec. 28, 2007 -- Astronomers have identified asteroid 2007 WD <br />5 in archival imagery. With these new observations, scientists at <br />NASA's Near-Earth Object Program Office at the Jet Propulsion <br />Laboratory in Pasadena, Calif have refined their trajectory estimates <br />for the asteroid. Based on this latest analysis, the odds for the <br />asteroid impacting Mars on Jan. 30 are now 1-in-25 -- or about 4 <br />percent.<br /><br />Note from David Morrison: In case of a close pass (but a miss), it is <br />normal for the impact odds to increase before they drop to zero. This <br />is because there is a time, as knowledge of the orbit improves, when <br />the error ellipse (the uncertainty in the miss distance) shrinks <br />while the target (in this case Mars) remains within the ellipse. Thus <br />the change in odds of a hit from 1 in 75 to 1 in 25 does not mean it <br />will hit -- it still has a 96% chance of missing -- but it sure is <br />interesting! It would be even more "interesting" if the target were <br />Earth not Mars. Think about it.<br /><br />-------------------------------<br /><br />WASHINGTON - Astronomers funded by NASA are monitoring the trajectory <br />of an asteroid estimated to be 50 meters (164 feet) wide that is <br />expected to cross Mars' orbital path early next year. Observations <br />provided by the astronomers and analyzed by NASA's Near-Earth Object <br />Office at the Jet Propulsion Laboratory in Pasadena, Calif., indicate <br />the object may pass within 30,000 miles of Mars at about 6 a.m. EST <br />(3 a.m. PST) on Jan. 30, 2008.<br /><br />"Right now asteroid 2007 WD5 is about half-way between Earth and Mars <br />and closing the distance at a speed of about 27,900 miles per hour," <br />said Don Yeomans, manager of <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[alokmohan]

Highly improbable.

 

[franontanaya]

Mars must be thinking: 'where is a 20,000km baseball bat when you need it...' <div class="Discussion_UserSignature"> </div>

 

[3488]

I really hope the impact does happen, think of what we can learn from it. Freshly exposed deeper<br />martian bedrock, settling of impact debris, a fresh reasonably sized crater that we can date<br />to the second.<br /><br />Of course there is a 96% chance that there will be no impact, but the odds of a whack are higher <br />than is usually the case, for this type of encounter.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[icemanmd]

I hope it hit Mars because if not it will be a bad day on earth on SEPT 22 2088 when it comes with in .0583 Au of earth. More then likely the change in orbit will make this possibly a earth hitter! Get out the marshmellows, and inner tubes. lol

 

[silylene old]

0.0583 au is still quite far from earth. But you bring up an interesting point, that there may be a small 'keyhole' in the Martian close pass which could alter that trajectory in a dangerous manner, if the asteroid passed exactly through it. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[icemanmd]

Not only that but I also noticed it "pulls up behind the planets" In almost every orbit it makes, I would surly think this will help speed it up slightly which throws the obit information out the window. Not to mention what a close miss with mars does to its orbit.<br />Will be a interesting month after it misses.......if it does miss mars lol. I hope it slams into the ground about 30 miles from oppy.<br />lol<br /><br />

 

[MeteorWayne]

I brought up that idea quite a few days ago, but further research has shown that the earth is in no danger. The primary reason is that the node of the steroid's orbit (when it crosses the earth's orbital plane) comes nowhere near the earth. The close approach to mars may speed it up or slow it down, but will not shift the orbit in a way that would allow it to intersect earth. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[comga]

Now on http://neo.jpl.nasa.gov/news/news154.html as of January 2<br /><br />New Observations Slightly Decrease Mars Impact Probability<br /><br />Additional position observations for asteroid 2007 WD5 taken on December 29 through January 2 have been used to improve the accuracy of the asteroid's orbit. As a result,the range of possible paths past Mars has narrowed by a factor of 3 and the most likely path has moved a little farther away from the planet, causing the Mars impact probability to decrease slightly to 3.6% (about one chance in 28)

 

[h9c2]

Isn't it interesting that apearantly there exist conditions under which there is a high degree of uncertainty about impact probability even 3-4 weeks before potential impact. <br /><br />This ought to have major consequences for how we evaluate a threat to earth. <br /><br />And not to derail the thread, but is there any feasible option for defense against an impactor at all?

 

[deapfreeze]

" is there any feasible option for defense against an impactor at all? "<br /><br />If Earth was going to be impacted we could throw a bunch of nukes at it and that will be done. <div class="Discussion_UserSignature"> <p><font size="2" color="#0000ff"><em>William ( deapfreeze ) Hooper</em></font></p><p><font size="1">http://deapfreeze-amateur-astronomy.tk/</font></p><p> </p> </div>

 

[brigandier]

>"If Earth was going to be impacted we could throw a bunch of nukes at it and that will be done."<br /><br />And instead of one large asteroid, we'd be bombarded by a few medium ones