Earth Under Threat From Dark Comets 149
An anonymous reader writes "Comets could be the most significant impact hazard to Earth, with sky surveys underestimating the number that are potentially devastating by a factor of between 10 and 100, UK astrophysicists say."
Slashdotted (Score:3, Funny)
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Here we go, try this article from New Scientist [newscientist.com], which has the same story.
Hazardous comets and asteroids are monitored by various space agencies under an umbrella effort known as Spaceguard. The vast majority of objects found so far are rocky asteroids. Yet UK-based astronomers Bill Napier at Cardiff University and David Asher at Armagh Observatory in Northern Ireland claim that many comets could be going undetected. "There is a case to be made that dark, dormant comets are a significant but largely unseen hazard," says Napier.
The article goes on to say that "dark comets are not unheard of. They occur when an 'active' comet's reflective water ice has evaporated away, leaving behind an organic crust that only reflects a small fraction of light."
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An organic crust? Produced by space borne microbes or what?
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Disclaimer: IANAC (I Am Not A Chemist)
Re:Slashdotted (Score:5, Informative)
Organic != made by life. Means nonmetals, so Carbon, Nitrogen Sulfur and related compounds.
It specifically means Carbon. There's really quite a bit of it about in space, and the process of evaporating off all the ice from the comet will mean that that which is there has been thoroughly concentrated to make something rather like soot. Such materials, especially in ultra-low gravity environments (so preventing the collapse of complicated micro-strucutres), are incredibly black, making the comet harder to see than a black cat in a coal cellar. At night with no torch.
The New Scientist article goes on to mention that the best hope of spotting these things may be in the infra-red range, as they'll be absorbing all the sunlight that falls on them and reradiating it. Sounds tricky to me, but just might work...
No torch? (Score:5, Funny)
are incredibly black, making the comet harder to see than a black cat in a coal cellar. At night with no torch.
Who uses torches in their "coal cellar"? What are you looking for, Frankenstein? ;-)
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Re:No torch? (Score:5, Funny)
Way too subtle. Remember, speakers of "the Queen's English" require giant, cartoon stomping feet to indicate humorous content is about to follow.
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Monty Python? Benny Hill? Blackadder? Douglas Adams? Rowan Atkinson?
Subtle innuendo has long been a staple of British humour.
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... and that comes from a guy who lives (?) in the country where they must add laughter to the TV series so you know there may have been something funny even if you didn't got it.
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What did you think that "giant, cartoon stomping feet" was a reference to, anyway?
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They haven't added laugh tracks to TV shows in years...
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I will say that I'm almost certain that Chappelle's Show had at least some canned laughter inserted. It was a bit too well-timed and consistent to have been natural. If it was meant as satire, it obv
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Monty Python? Benny Hill? Blackadder? Douglas Adams? Rowan Atkinson?
Subtle innuendo has long been a staple of British humour
Benny Hill? Subtle innuendo? What are you, French?
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Pretty much every sitcom for kids uses a laugh track. Real kids would laugh at inappropriate times, and real adults wouldn't laugh at all. I swear to God, if my kids ever want to watch Nickelodeon, I've failed.
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You mean like Red Dwarf [wikipedia.org]? Or Last of the Summer Wine [wikipedia.org]? Most British comedies either use, or sound like they use, laugh tracks, although I can't find an authoritative list anywhere. The technique pretty much died in the 90s here in the "colonies," aside from in kids' shows and when used as satire.
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In places that speak the Queen's English, rather than American, a device with batteries and a light bulb is called a "torch", rather than a "flashlight".
I thought we called them "flashlights" because they traditionally include a momentary switch one can use to turn the light off briefly without wearing out the sliding power switch (i.e. make them "flash"), but apparently (and according to Wikipedia [wikipedia.org]) it was due to problems with the earliest models' choice of filament (inefficient carbon) and battery (zinc-carbon, which had difficulty sustaining current) only being able to operate for brief periods (flashes).
And speaking of the Wiki, Lumencraft's Gatlight [lumencraft.net] res
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You know you are likely to be eaten by a Grue.
http://www.youtube.com/watch?v=4nigRT2KmCE [youtube.com]
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Such materials, especially in ultra-low gravity environments (so preventing the collapse of complicated micro-strucutres), are incredibly black, making the comet harder to see than a black cat in a coal cellar. At night with no torch.
How much more black could they be?
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none more black.
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I Call FUD Anyway (Score:5, Funny)
It's down for a sinister reason! They don't want us to READ the articles and become informed of the truth!!!
Also, why the racism? Just because the comets are DARK doesn't mean they are evil. RACISTS!
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Launch Nukes (Score:1)
We need to destroy these communist comets before they damage our strong and beloved economy!
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You know... This is not as absurd as it may sound.
Dark comets are black to visible light, but if we could tune a nuke to produce whatever wavelengths they do reflect (and they do reflect some or they would be radiating a lot of infrared), we could detonate a few in deep space to track the reflections.
Of course, we would need better observation capabilities - we would be observing large patches of sky in search for perhaps very faint reflections for the first pulses and then zero in the regions where the ori
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Communism isn't even what Communists think it means.
Another reason for fear (Score:4, Insightful)
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Hey! Look up there! Watch out for that
Re:Another reason for fear (Score:5, Funny)
...If I have to start worrying about the sky falling on me...
Vitalstatistix, Is that you?
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My wife is a worry-wart and I use this argument against my spouse for doing things: I could walk outside and have my head replaced by a falling meteor. Does that mean that I shouldn't go out today? The chances for that are enormous to the point of why should I even worry about it? I can't let the possibility of bad things happening overshadow the probability. Probability is what we should be using in risk modeling, not possibility, because hey, anything is possible .
I mean hey, with the crash of that
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Probability over time (Score:1)
It's unlikely, but not impossible that the Earth be struck by an astronomical object large enough to wipe out life as we know it today, tomorrow, or even in your lifetime. In the fullness of time however it's not just likely, it's certain.
That's what it's like when you play the odds. The likelihood of any two satellites colliding in orbit is very low, the odds of two submarines colliding in the vast ocean are also unlikely. But roll the dice long enough and they'll come up boxcars twelve times in a row.
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Seriously? WTF? (Score:5, Insightful)
"Comets could be the most significant impact hazard to Earth
Just what are the "other" impact hazards? I'm very curious about this.
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You need to get out and watch more movies, seriously :)
Re:Seriously? WTF? (Score:5, Informative)
Asteroids.
Asteroids orbit nearer the Sun, and many of them have paths that cross Earth's orbit quite frequently. They're a menace all right, but a menace that can be mapped and measured. Comets on the other hand have long, highly elliptical orbits that carry them far from the Sun. Though any given comet won't pass near the Earth anywhere near so often, they exist in colossal numbers, and for all we know one could come barrelling out of the dark to kill us all next month. We could in principle track every rock of dangerous size in the inner solar system. We haven't a prayer of tracking all the comets.
Re:Seriously? WTF? (Score:4, Interesting)
Though any given comet won't pass near the Earth anywhere near so often, they exist in colossal numbers, and for all we know one could come barrelling out of the dark to kill us all next month.
Sounds like there's not really any reason to worry about it then if there's nothing we can do. Isn't that the definition of FUD?
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Sounds like there's not really any reason to worry about it then if there's nothing we can do.
If the utterly false statement that "there's nothing we can do" were true, you'd have a point there.
Isn't that the definition of FUD?
No. In fact, it's almost entirely unrelated to FUD in the usual sense. FUD usually involves getting you to choose one option over another due to spurious reasons, e.g. choose product A because product B is open-source so the bad guys can insert exploits into the code (they accept contributions from anyone, after all -- this was an argument my old boss made). Trying to move people from a situation where the
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Simple comet defence, in fact I already pointed it out once as a simple satellite defence system. Simply create massive mirror arrays, say about a 1.5m by 1.5m mirror hooked up with electronics so you can accurately gauge the position of a mirror and encrypted wireless electronics to control mirror facing. Your looking at some where between $250 and $500 per mirror. Now the mirrors do even need to be in one location but can be distributed through out the country and we are not talking 2,000 or 5,000 thousa
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Design a cool screensaver that the monitor will display while my computer is running this, and I'll sign up.
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So we've got the options of panic and willful ignorance out there.. how about a third option like developing technology to improve detection or damage mitigation.
Nah.. that's just crazy talk.
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>>"Comets could be the most significant impact hazard to Earth
>Just what are the "other" impact hazards? I'm very curious about
>this.
Asteroids are the other impact threat. There is also a small risk from man-made space junk. The biggest threat is comets because they tend to be moving far faster than asteroids typically do (near parabolic orbits vs low-eccentricity elliptical orbits), so the kinetic energy in a comet impact can be much higher than in an asteroid impact. Another problem with co
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...so it can be very hard to detect them before the impact shockwave turns us to jelly.
Mmm... jelly.
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Re:Seriously? WTF? (Score:4, Funny)
sperm wales and pertunias...
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Cars are a pretty dangerous impact hazard on Earth.
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Just what are the "other" impact hazards?
Mutalisks.
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Just what are the "other" impact hazards?
Mutalisks.
If Mutalisks were ever going to be a hazard, we'd be killed by a Zergling rush long before the Mutalisks got here.
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Bombardiers (Score:2)
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Just what are the "other" impact hazards? I'm very curious about this.
Planet X, of course!
Extrasolar objects (Score:2, Interesting)
Somebody else covered asteroids, so I'll touch on another risk: extrasolar objects. You see, a lot of discussion is made of object in our solar system because they are things we have to study for long periods of time; we can see them. However our solar system is orbiting the center of our galaxy in concert with a vast quantity of other material. Things can and do achieve escape velocity from our solar sytem, like the Voyager probes.
Not all the mass in our galaxy belongs to a star. Some of it - the remn
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Just what are the "other" impact hazards? I'm very curious about this.
Debris from colliding satellites
Could be? (Score:2)
What else is out there that might be an impact hazard?
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With massively, massively lower probability than comets or asteroids: small black holes. Black and brown dwarfs. And interstellar planets (which have been posited to exist).
Given that we don't know what (most) dark matter is, maybe there are other possible surprises. But dark matter seems to be very unclumpy.
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Russian satellites? Asteroids? Anything out there other than a comet that has mass?
DCC Trading (Score:5, Funny)
My greatest fear is that people will view this as something that they have no control over, thus inducing a sense of complacency. Complacency kills!
But there is hope. I propose a Dark Comet Credit (DCC) trading system, whereby planets that are in danger of being struck by dark comets purchase dark comet credits from planets that aren't in danger.
It may not be a perfect plan, but it's better than doing nothing.
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"What, you mean like carbon credits? Getting hit by a comet is not the same as pumping pollutants into your neighbor's air. I can't imagine what kind of diseased mind managed to make that connection."
Lighten up, Francis.
Don't worry (Score:2)
With the rate that things are colliding recently, any comet will be taken out by an asteroid, satellite or stray sub way before it gets near a population centre
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any comet will be taken out by an asteroid, satellite or stray sub way before it gets near a population centre
Fair enough, but:
1) How are we going to get those Subway restaurants to stray?
2) What will happen to all those $5 foot longs after the impact?!?
don't be so judgmental (Score:5, Funny)
Just because these comets hang out in the furthest, coldest reaches of the solar system, don't reflect light all that well and listen to cradle of filth, that doesn't make them all dark! Goth, maybe, but not dark. You just don't understand them.
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They're not Goth Comets! They're Vampire Comets!
Don't you know the difference?
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It's the Emo comets that really piss me off.
my modest proposal (Score:2)
if we discover a dark comet too late for the standard "shoot a nuke" at it solution to work, I propose we build a warp field around it and jump it THROUGH the planet... this idea is 100% original.
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That way next time the Earth is threatened by a dark comet coming to obliterate us, in order to use that idea everyone would have to pay you royalties and you'll clean up! Why this idea is even better than One Click(TM)©!!!!
Threat From Dark Comets??? (Score:3, Funny)
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And we don't want to pay taxes. Ever.
Oblig.... (Score:4, Funny)
Shouldn't we put brown paper bags over our head or something?
If you like.
Will it help?
No.
I knew it! (Score:2)
I knew it all along.
All the quarters spent in the arcade was really an investment in a space fighter pilot training program. Humanity will thank me when I show off my real comet busting mojo!
when London gets a foot of snow (Score:2)
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Well, invisible asteroids could have an actual impact on the planet.
Saving the planet from global warming is rather silly. The planet will be fine. It's survived not having an atmosphere before and I bet it can do it again.
Global warming could change human life as we know it. Primitive humans made through an ice age (good thing they didn't have carbon and fuel taxes back then). I would expect modern man to be able to ride out the heat. Either way, the planet won't care.
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Sure, that'll work... (Score:1, Offtopic)
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Details, details (Score:2)
My much longer summary didn't get used, so I'll pass out some relevant links.
NASA Near Earth Object program: http://neo.jpl.nasa.gov/index.html [nasa.gov]
Impact risks are within. Pertinent to this article are the size estimates which are based on albedo (visual reflectivity) and so the mass and impact damage estimates.
The UK research team calculated that there should be 300 to 3000 dark comet bodies in system. We know of about 25, so there may be up to 100 times more. Current known Near Earth Asteroids total around 60
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Consider a spongey body made of soft, runny (with chunks), powdery carbonaceous materials (including hydrocarbons) [...]
What?! There may be hydrocarbons on these things?!?
Well, why didn't you say so? We'll invade tomorrow.
Of all the ways to go (Score:3, Funny)
Impacts are good (Score:1)
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If it weren't for this massive impact some 65k years ago we would still be voting for lizards
I know we Americans don't pay much attention to the SI system, but you might want to check your prefixes.
More fear .. (Score:1)
Giant space goat. coming, Earth doomed. (Score:1)
Oh no... (Score:2)
It's the Comet Empire! [comet-empire.com] Where the Argo when we need her?
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That strikes me as dubious. Way too long. Tunguska was a relatively small impact, comparable to a decent-sized H-bomb; the figures I've heard bandied around for how frequently those can be expected are typically two or three centuries between events.
while a continent destroying impact was a one-in-60-million-year event.
That makes more se
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Actually, impacts the size of the Yucatan K/T event are global in scope, and do not occur on average every 60 million years. Even if every major extinction event was caused by a an impact (which is highly doubtful), they are much more widely spaced than a sixty million year average.
Maybe what we're looking at is something more like the Younger Dryas impact event [wikipedia.org] hit every 60 million year on average. Which, though unlikely, would of course be a major fricken disaster for humanity if it happened within our li
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Maybe your numbers are correct, but being hit by a dark comet will probably result in 1,000,000,000 times more damage to the planet than a stray satellite would.
A satellite normally hits at no more than orbital speeds and asteroids and comets hit at speeds much higher. Not to mention they have much higher mass.
And yes, we can do something about it. We just haven't figured exactly what.
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"We've figured out lots of things we could do. We just can't (economically) do any of it yet"
In other words, we haven't figured out what to _do_ about it. We have only figured out a lot of things we can further figure out.