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Earth Under Threat From Dark Comets
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."
Already down. There goes my chance of calling FUD.
Posts not to be taken literally. Almost everything is sarcasm.
We need to destroy these communist comets before they damage our strong and beloved economy!
The dangers of knowledge trigger emotional distress in human beings.
C'mon, there are hundreds of ways for me to die everyday. If I have to start worrying about the sky falling on me, I might as well pack it in now.
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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.
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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!
The dangers of knowledge trigger emotional distress in human beings.
What else is out there that might be an impact hazard?
Mod me down with all of your hatred and your journey towards the dark side will be complete!
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.
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
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.
Kwisatz Haderach
Sell the spice to CHOAM
This Mahdi took Shaddam's Throne
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.
Hurry up! Find Bruce Willis!!!
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? ;-)
Shouldn't we put brown paper bags over our head or something?
If you like.
Will it help?
No.
I say don't drink and drive, you might spill your drink. Before you get behind the wheel just stop and think.
"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.
"As God is my witness, I thought turkeys could fly." A. Carlson
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!
The perpetual worry-warts in the UK then shift to worrying about invisible asteroids instead of global warming.
http://news.bbc.co.uk/2/hi/americas/7891770.stm
The world is made by those who show up for the job.
Actually, that's more or less the point. Without a better idea of the number of dark comets in Earth-crossing orbits, any estimate of the risk is highly speculative, and that's a problem. We don't know what the actual risk of an impact is, and ignorance is inherently risky. It may be that if the numbers were known, the risk would be as low as Francis estimates, or it may be ten or a hundred or a thousand times greater. Any guess at this point is speculative. A lot of us would sleep better with more hard data instead.
"Convictions are more dangerous enemies of truth than lies."
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 sense. The last of these would have been 65 million years ago in the Yucatan.
Real Daleks don't climb stairs - they level the building.
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
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 6000, with a similar estimate of ratio of known to unknown (1 : 10 to 100). Thus dark asteroids might be around 1% of total impact threat. It's how easily they're located that's the subject of TFA. We know they exist. Deep Space 1 investigated one of them.
Comets are listed under by the NEO program as Near Earth Comets. TFA stresses that completely outgassed comets may not appear easily in visible light as they would be mostly carbonaceous at the surface and have little coma. These would be pretty much invisible to visible light telescopes which are what are used by the NEO program. They would be more easily detected in the infrared (absorbed visible light has to re-radiate, and does so as heat). Space telescopes such as Spitzer would work great. Figure the odds on getting such devices brought to task when there's more 'important' science to be done.
The mass of these objects would be far less than similarly sized rocky bodies, and they would tend to be smaller overall. Consider a spongey body made of soft, runny (with chunks), powdery carbonaceous materials (including hydrocarbons), light gasses such as methane and some water. Cram that sucker into the atmosphere at miles per second. It will deform and take on the shape of the bow shock. The materials will vaporize and the hot vapor will be forced into the oxygen of the atmosphere. Given the relative softness, there's a good chance such a body will explode as an air burst rather than impact the surface/ocean.
An air burst including rapid oxidation of the material at the bow shock would look much like a fuel/air bomb: rapid expansion followed by implosion due to oxygen depletion. Say, 100 square miles of trees knocked down around ground zero but no visible burning because the burst would be at altitude. No remenants to be found because it all burnt up. Tunguska. Mass estimate 1/3 that of a rocky body.
Fearmongering? Three points:
1. 2008 TC3 was discovered October 6 2008. It was predicted to impact the next day. It did, over Sudan. It happens, several times a century, and now we know we can predict them correctly.
2. Dark cometary bodies would be harder to detect, with larger bodies being discovered only this early, if at all. If limited to ground based telescopes, the 'if at all' applies.
3. Impact risks are calculated per body. As more are detected, total known impact risk grows. Sum down the 4th column (cumulative impact risk) of the tables at http://neo.jpl.nasa.gov/index.html to get the total cumulative impact risk over the next 100 years for the bodies presently known. As a rough estimate, multiply by 10 to include the bodies not yet detected.
It occurs to me that an individual might be responsible for causing an auto accident several times during their life time. Call it 'several times per century'. The risk is similar to that of an impact by a near earth object. If the combined cumulative impact risk estimate is, in your estimation, inconsequential, put your money where your math is -- drive around without insurance.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
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.
http://www.dieblinkenlights.com
you posted on the wrong article .. the NY tax thing is up a few.
Go go Gadget Nailgun!
Of all the ways to go, at least here is one where you don't have to say, "Well, that was a bonehead thing to do..."
End anonymous moderation and posting on
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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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 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 lifetimes.
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 remnants of supernovae, agglomerations of interstellar dust, stray comets ripped away but not captured by close passing stars - wanders the dark realm between the stars. This stuff is hard frozen and the vast majority of it is fine dust. Unfortunately not all of it is. The Earth is struck by extrasolar meteors every day, and some of them have good size. Because of their different origin they can be moving much faster relative to the Earth than an object that's been circling our common star for billions of years.
It would be unfortunate if we were struck by one of these objects that is a mile or more in diameter.
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If it weren't for this massive impact some 65k years ago we would still be voting for lizards
Yeah that's it, let's introduce more fear, so we can all buy stress relief pills, and go to our leaders for protection, regardless how lousy those leaders are.
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We've figured out lots of things we could do. We just can't (economically) do any of it yet, with the possible exception of tossing nukes at the problem. Of course, nukes (or other explosives) have the potential to make a "bullet" hit into one spot on the planet into a "pellet cloud" that hits lots of places at once ...
krenshala
If I'm going to sleep on it, I think I'd prefer soft data ...
I definitely agree we need more data in order to make any kind of even remotely accurate prediction of probability, however.
krenshala
It's the Comet Empire! Where the Argo when we need her?
If you had meant to post here, that would with have been sublime. or at least generally subcitric.
Atlas Shrugged : Thematic Story
Astrophysicist Dr. Louis Frank first proposed the existence of small dark comets in 1986. In 1990 he wrote 'The Big Splash' where he theorized that most of the Earth's oceanic water, and probably life itself, resulted from small comets that enter the atmosphere at the rate of more than 20 per minute. It's an intriguing read that needs to be taken with many large grains of salt. He was roundly criticized and ridiculed for his theory and these days he doesn't talk much about it anymore. His current profile at the University of Iowa makes no mention of his dark comet research.
The guy is no lightweight. He worked with James Van Allen and co-wrote with him several papers describing what we now know as the Van Allen radiation belts that circle the Earth. Is he about to be vindicated?
"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.
http://www.dieblinkenlights.com
These are useful terms. A simile is where you say "this thing is like this other thing". A metaphor is where you say "this thing is this other thing". Hyperbole is when you say "I told you a billion times this was going to happen".
I doubt China needed to include a satellite killing device in a satellite that weighed half a ton that intersected the orbital path of another satellite at 6 kilometers per second. That would be redundant. The chinese are not famous for wasting money.
Help stamp out iliturcy.
Well that's just perfect, now we have to face planet killing ninja comets.