# Can we really dodge a big asteroid?

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##### Guest
The theory seems to be that if we can predict a collision far enough in advance (10 to 30 years), we can do something about it - like deflect it a little so that little nudge will turn into a big miss a decade later.<br /><br />But, the farther ahead you predict the motion of an object, the more error there is in your calculations. Seems that little nudge could just as easily turn a near miss into a hit.<br /><br />But, if you wait until the thing is close enough to accurately predict its path, then it's too late to deflect.<br /><br />So, it seems we might as well stop worrying about these things - there's nothing we can do about it anyway.

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#### MeteorWayne

##### Guest
Just because the error is larger the further out you go, doesn't mean you can't shift that ellipse of uncertainty away from the earth so there's no chance of it intersecting us.<br /><br />That's the idea. with enough lead time, and a shove in the right direction, even the error bars won't hit us. <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>

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##### Guest
OK. I hope they double check their arithmetic ...

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#### pyoko

##### Guest
"....if you wait until the thing is close enough to accurately predict its path, then it's too late to deflect. "<br /><br />Don't underestimate the power of a huge nuke (or ten). <div class="Discussion_UserSignature"> <p> </p><p> </p><p><span style="color:#ff9900" class="Apple-style-span">-pyoko</span> <span style="color:#333333" class="Apple-style-span">the</span> <span style="color:#339966" class="Apple-style-span">duck </span></p><p><span style="color:#339966" class="Apple-style-span"><span style="color:#808080;font-style:italic" class="Apple-style-span">It is by will alone I set my mind in motion.</span></span></p> </div>

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#### MeteorWayne

##### Guest
Don't overestimate it either. A few weeks in advamve a dozen nukes will make no difference. <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>

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#### vogon13

##### Guest
Many more ways for it to miss, rather than to hit. Not that a particularly unlucky concatenation of events could turn a near miss into catastrophe.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

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#### nexium

##### Guest
Likely that is the reason there is only puny funding for nudging asteroids. We need more accurate orbit data for about 10,000 asteroids. A telscope somewhat like Hubble, but in solar orbit would help us improve the accuracy of decades in the future orbital paths.<br />Perhaps more important we need to learn to do accurate 4 and 5 body orbit calculations. Neil

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#### jgreimer

##### Guest
How would you propose to use nukes on an asteroid? On what size of asteroid? A nuke may turn a big asteroid into a bunch of smaller asteroids. Some asteroids are loose conglomerations of rocks. A nuke probably wouldn't do much with that. Asteroids most likely are spinning. How would you detonate a nuke on a spinning asteroid? (Answer: The nuke would have to be detonated at one of the two points where the axis of rotation intersects the surface. Presumably one would be better than the other but it may be that neither would very efficient. If the nuke were detonated at the right distance below the surface, it may blow out enough material to move it slightly.)

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#### weeman

##### Guest
The number of nukes used would depend on the size of the asteroid. If we could break apart the asteroid when it is still a good distance away (perhaps in the far reaches of the outer solar system, or farther) then it should lessen the chances that even the smaller pieces would hit Earth. If nukes were to blast it apart into smaller pieces, then the smaller pieces would have new trajectories, different from that of the asteroid before it was blown apart. <br /><br />At least this is what we hope might happen <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

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#### olivebird111

##### Guest
YES, your concept is very easy to counter, for example, NEOs search 100 years into the future, therefore, we have time.<br />And also, please dont pull that nuke garbage on me...one nuke..if we can find a missle laucher to shoot it, will only create 10000 pieces of rock into the atmophere

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#### tony873004

##### Guest
<i>"We need more accurate orbit data for about 10,000 asteroids"</i><br />Our orbital data, including error bars is accurate enough to exclude all known asteroids from an Earth collision in the next hundred years, with the exception of Apophis in 2036. It will pass through a very chaos-inducing area, including a collisional keyhole in 2029. Still, the odds of it impacting in 2036 are in the tens of thousands to one.<br /><br /><i>"A telscope somewhat like Hubble, but in solar orbit would help us improve the accuracy of decades in the future orbital paths."</i><br />Especially if it orbited interior to the Earth's orbit, so it could pick up some of the interior asteroids that are virtually undetectable from Earth. It would be even nicer if we could put it in a retrograde orbit to vastly increase the encounter speeds with asteroids, although the delta v required renders this retrograde orbit a pipe dream.<br /><br /><i>"Perhaps more important we need to learn to do accurate 4 and 5 body orbit calculations."</i><br />We already can. We've landed spacecraft on 2 asteroids, and collided on-target with a comet. The methods used by the space agencies include Newtonian N-body, with pertabutions from HUNDREDS of solar system bodies, GR, SR, galactic tide, and solar radiation.<br /><br /><i>"If nukes were to blast it apart into smaller pieces, then the smaller pieces would have new trajectories, different from that of the asteroid before it was blown apart. "</i><br />Yes. And that is why I feel nuking it would be a viable option.<br /><br /><i>And also, please dont pull that nuke garbage on me...one nuke..if we can find a missle laucher to shoot it, will only create 10000 pieces of rock into the atmophere. </i><br />We wouldn't use a missle launcher. We'd use a rocket capable of interplanetary travel. Read his post more carefully. If the 10000 pieces of rock spread out over millions of kilometers, then they couldn't possibly all hit Earth, as Earth is a target of about 12,000 km

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#### alokmohan

##### Guest
Instead of wasting time on fall of asteroid can you not do anything useful.

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#### nexium

##### Guest
Not useful in 2007, but concepts discussed here may make a good asteroid shield possible by 2020, but the details need to be understood before it is likely we can develop effective deterance. Great advances in technology are typically preceeded by decades of talk on possibly related topics.<br />We would likely have luxury hotels five kilometers above and below sealevel, if great minds had been focusing on related possibilities since 1960. Neil

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#### pyoko

##### Guest
Sorry if someone already posted this, but what if we fly to the said asteroid, plant a huge engine on it, and just gently push it the right way? It's like flying an asteroid. Or would using nukes and the asteroid as a blast plate like Orion be better? <div class="Discussion_UserSignature"> <p> </p><p> </p><p><span style="color:#ff9900" class="Apple-style-span">-pyoko</span> <span style="color:#333333" class="Apple-style-span">the</span> <span style="color:#339966" class="Apple-style-span">duck </span></p><p><span style="color:#339966" class="Apple-style-span"><span style="color:#808080;font-style:italic" class="Apple-style-span">It is by will alone I set my mind in motion.</span></span></p> </div>

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#### nexium

##### Guest
The huge engine and gently is likely best. The Orion designers had a considerable debate on the specs for the blast plate, so there is a reasonable probability that a typical asteroid would not be a satisfactory blast plate. The probability is high that the asteroid would separate into 2 or more peices (perhaps thousands of peices in a vast range of sizes) even if many small nukes were used as in Orion. The Orion concept is largely untested, but many think Orion looks good on paper. Neil

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#### nexium

##### Guest
Hi tony: "accurate enough to exclude all known asteroids except..." all tends to alert my suspicion. Likely several small asteroids were spoted by amatures with only approximate co-ordinates and time, so there was some doubt it was the same asteroid that was tracked with small error bars later. Since we find a previously uncharted asteroid most nights, I'm not confident of our near term safety. Also, several main belt asteroids, become near earth asteroids most years. Perhaps many per year if you count stadium size asteroids. Neil

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#### qso1

##### Guest
askold:<br />So, it seems we might as well stop worrying about these things - there's nothing we can do about it anyway.<br /><br />Me:<br />I agree with you that if we try to develop a deflection capability...it might not work but I'd rather put something into place just to be on the safe side...just in case it did work. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

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#### astroguard

##### Guest
tony873004 wrote:<br /> <br /><i># Our orbital data, including error bars is accurate enough to exclude<br /># all known asteroids from an Earth collision in the next hundred years,<br /># with the exception of Apophis in 2036.</i><br /> <br />It's not the *known* asteroids we need to worry about.

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