posted
Alright it's already passed, and missed by 2&1/2 months. But nonetheless, I'm surprised that I'm the first who seems to have picked up on this.
"Go outside after sunset and face north. The green Comet Linear VZ13 is gliding through Draco a few star hops from Polaris. Too dim for naked eye, but easy to see in 7X35 binoculars." [/paraphrase] For more info. Check out the 3D-orbit link, and play with the Java scroll bars to shift viewpoints. Coulda been one HECKUVA space SPECTACULAR. And we just missed it.
On 15Augus2007, the Comet/2006 VZ13 (Linear) nearly passes through the point which Earth occupied on 27May2007. Since aphelion was on 7July2007, Earth was somewhat close to that apehelion (farthest distance from the Sun) of 1.01671AU on 27May2007. CometVZ13 will cross nearly the same point at ~1.018AU from the Sun on 15August2007.
ie On 15August2007, VZ13 will come within ~0.002AU of a point that Earth occupied on 27May2007.
Another cute factoid, VZ13 will be between 1.015AU and 1.016AU from the Sun between 9August2007 and 12August2007; less than Earth's aphelion distance, but at a point above Earth's orbital plane.
Fortunately, that 2&1/2 month difference and steep orbital inclination means that the closest VZ13 will get to Earth is 0.575AU on yesterday and today.
Lest we get complacent, the 2006 in C/2006 VZ13 is the discovery year. If that Earth-crossing comet had come 2&1/2 months earlier on a slightly altered trajectory allowing intersection with Earth, there would have been nothing that we could have done about it in the time frame between discovery and impact.
Couldn't find a mass estimate, but comets tend to be large, much larger than the Earth-crossing asteroids that we've fretted about. Now consider the results of a Chicxulub-sized cratering event on our civilization.
Posts: 8501 | Registered: Jul 2001
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posted
I'm going to ask the my co-worker/astronomy buff/telescope guy if he has been watching this. I hadn't heard about it...
Posts: 9538 | Registered: Aug 2003
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posted
How long, if ever, will it be before we have the technology and resources to save ourselves from this sort of event? I think it's one of those things you just have to not worry about, because if it happens, we're hosed.
Posts: 3950 | Registered: Mar 2006
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posted
Wow! Someone cares! Awesome! MightyCow, I think we're probably 20 years and a few billion dollars away from having something that would be effective against most asteroids and comets we'd be likely to see. In other words, it's very doable, and very worthwhile, once people realize the danger.
Posts: 6246 | Registered: Aug 2004
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posted
I was under the impression that most ideas for stopping comets were less effective than a star wars missile defense system. We can't even manage to get a shuttle into earth orbit in a reasonable time frame. It seems that our space exploration capacity would need to be so much more advanced than it is now, so much better funded, and specific steps would have to be taken toward this particular goal.
Is anything like that really in the works? Do people have workable plans on how to realistically launch a vehicle and divert a comet within the relatively short window of warning we might have?
Posts: 3950 | Registered: Mar 2006
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posted
There are plans but no actual construction projects that I know about. The answer depends on how much lead time you have before the thing hits. If you know many years in advance, it's best to land and gently push it off course with ion drives or something similar. If it's short lead-time then you have to blast it with nukes, but the problem with that is that you can't just atomize it, you have to actually knock most of the material into totally different orbits. Otherwise you get hit with a bunch of pulverized rock or whatever and the kinetic energy incoming is nearly the same. The kinetic energy is the part that is most destructive when it hits our atmosphere. You get stuff like oceans boiling and the sky baking like a 700 degree oven and things. Then the forests all burn at once and you get nuclear winter from the soot and ejecta and all that. Not fun.
Posts: 6246 | Registered: Aug 2004
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posted
Maybe we'll get lucky and the conquering aliens will come at the same time as the doomsday asteroid, and they'll cancel each other out.
Posts: 959 | Registered: Oct 2005
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posted
People don't know well enough to get themselves to stop smoking and we expect them to lobby their Congressman about asteroid defense?
If we can't get people to care about things that are easily stopped, how do you get them to care about something vague, that they can't see the effects of, and faraway that might never even happen?
Posts: 21898 | Registered: Nov 2004
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posted
A personal inability to quit an addictive habit does not equal an inability to have convictions, make decisions or see those decisions through to the end.
Posts: 2596 | Registered: Jan 2006
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posted
Even Winston Churchill smoked, and he would have found a way to destroy a comet.
quote:ie On 15August2007, VZ13 will come within ~0.002AU of a point that Earth occupied on 27May2007
1 AU is about 93,000,000 miles. Multiply by 0.002, and you get 186,000 miles. That's significantly closer than the Moon.
With the little warning that is available with such an event, the best we can do is evacuate and cross our fingers. Given the magnitude, this particular comet doesn't seem to be very big compared to other comets that have been more recently notable. I'll have to do some searching to be sure.
Posts: 684 | Registered: Jun 2002
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posted
If Liv Tyler, Bruce Willis, and Leelee Sobieski can't convince America to take this threat seriously, I don't think we have much chance Posts: 3950 | Registered: Mar 2006
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posted
I wonder if, assuming for a moment that there are aliens occasionally or regularly visiting here, if they would actually move an asteroid to save us. You'd think, right?
Posts: 3354 | Registered: May 2005
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Blayne Bradley
unregistered
posted
Unless they have a Prime Directive.
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I wonder if some races might be such extremist crazies that they'd follow such a Prime Directive in such a case.
OTOH, the kind of science necessary to travel in space doesn't usually come from societies whose members are willing to be that devoted to a principle. China (which has the brains but not the common sense) and the Middle East (fundie Islam) come to mind.
Posts: 3354 | Registered: May 2005
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posted
Not really. The Moon and the Sun have thousands of times more tidal effect on Earth than any passing asteroid or comet.
Because the 0.002 AU was an approximation, it's possible that the comet could have come within Earth's Roche Limit, which is about 34,390 km for a solid body, according to Wikipedia. I think this was unlikely because the comet could easily have been that much further away.
Had that happened, the comet would have broken up and then could have possibly gone into a long-term parabolic orbit that would eventually allow it to impact Earth decades from now. This is what happened to Shoemaker-Levy 9 around Jupiter.
quote:Tracing back the comet's orbital motion revealed that it had been orbiting Jupiter for some time. It seems most likely that it was captured from a solar orbit in the early 1970s, although the capture may have occurred as early as the mid-1960s.[2] No precovery images dating back to earlier than March 1993 have been found so far. Before the comet was captured by Jupiter, it was probably a short-period comet with an aphelion just inside Jupiter's orbit, and a perihelion interior to the asteroid belt.[3]
However, that's also unlikely to happen to Earth as often as it does to Jupiter (on a cosmic timescale of course) because Earth is so much smaller. A direct impact is more likely.
Thisis as close as we get to an impact in the near future.
Posts: 684 | Registered: Jun 2002
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