back to article Asteroids as powerful as NUCLEAR BOMBS strike Earth TWICE YEARLY

A study using data from monitoring stations designed to enforce a nuclear test ban treaty shows that the Earth is enduring far more dangerous asteroid impacts than previously thought. Between 2000 and 2013, the Earth was hit by 26 asteroids that exploded with a force of between one and 600 kilotons – an average of one every …

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A shooting gallery

Someone once said a long time ago (and I tried to google this but only got recent results) that ..."we live in a galactic shooting gallery."

There is more and more evidence that there have been past fairly advanced civilizations and societies that have fallen due to extreme changes in environment.

Too bad we still haven't learned THAT lesson.

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Anonymous Coward

Blind Luck?

Or simply the odds?

Planet is 75% covered in water. And 95% of what's left is virtually uninhabited: deserts, great swaths of tundra, lovely forests, huge farms growing wheat.

So roughly 99% of the time, who cares?

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Re: A shooting gallery

Thumb down? Why?

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Re: Blind Luck?

The odds aren't as good as you seem to think.

Roughly 1% of the earth's surface is considered "urban". (Source.) Two strikes per year means, over a 50 year period, there's a 64% chance at least one town/city will get, at the very least, a Chelyabinsk-style light show.

Chelyabinsk got lucky, in that their meteor entered the atmosphere at a very shallow angle. Had it hit square-on, the city would have been pretty much flattened. So the question is, what proportion of those "2 a year" are actually (a) large enough and (b) squarely aimed enough to inflict real damage on the ground?

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Dumb Luck?

Talking statistics is talking rubbish.

The article says that none has ever seen any sign of thes things until after they happen. How the hell do they manage to miss every one of them when they are as common as solstices?

And how come none of these things have ever hit the moon?

Or did you all think that lunar craters are nearly perfectly symmetrical because that how meteor strikes operate on the moon as opposed to the ones that hit earth?

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Anonymous Coward

I can live with that!

I am just annoyed that, so far, the asteroids have missed Goldman Sachs and Saudi Arabia.

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Re: A shooting gallery

It's ironic that you should try to crowbar-in your Anthropogenic Global Warming sentiments here, because de-industrialising or depopulating the human race (which is what every single "mitigation" proposal that I have seen ultimately amounts to) is only going to render us yet more helpless in identifying and averting potential asteroid extinction-level events.

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Re: Dumb Luck?

The craters on the moon ARE impact craters. And they're mostly symmetrical because only near-grazing impacts form craters that AREN'T. That's what happens at cosmic speeds. The sheer energy of the impact blasts material near-equally in all directions long before such trivia as impact direction have any chance to influence things.

The effect was first confirmed back in the early 20th century, using rifle bullets fired into mud, by Daniel Barringer (the man who also showed that Meteor Crater in Arizona was precisely that).

For a more detailed explanation, see, e.g., http://www.scientificamerican.com/article/why-are-impact-craters-al/ . Or www.barringercrater.com has classroom instructions on how to demonstrate the effect.

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Re: I can live with that!

Saudi Arabia is mostly a vast desert. It has a population of just under 30 million people in a country just a little smaller than Greenland.

It's a fair bet they get lots of meteor hits.

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er ... wot?

'When the earth wandered into the path of a comet.'

'Wander' means to move randomly, aimlessly and without purpose. I kind of got the impression the earth followed a set route around the sun every year. If it were to digress from, for example to visit Mercury or Neptune, asteroids would be the least of our problems.

(and yes, I know the solar system is proceeding through the galaxy too, but that's a different issue)

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Re: er ... wot?

Perhaps the author knows that the word "planet" is derived from a Greek word that means "wanderer"..

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Re: er ... wot?

Wanderers? Wasn't that the other planets?

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Re: er ... wot?

Wanderers? Wasn't that the other planets?

Yes that's right, when viewed from this planet. And if you go stand on Mars you'll see that Earth wanders across the stars just like the other planets do.

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Anonymous Coward

"I kind of got the impression the earth followed a set route around the sun every year"

I hate to be a pedant (well not actually, I quite like it) but you got the wrong impression. Anything over 2 bodies and gravity gets a bit complicated. The "route" you describe is unpredictablein a certain sense and can only be approximated computationally.

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Re: "I kind of got the impression the earth followed a set route around the sun every year"

I was in a lecture the other week by Cedric Villani, and he said that the latest data says that the current solar system is stable for at least the next million years or so, so three-plus body problem stuff isn't so important on the time scales we are likely to worry about.

The classical three-body problem involves two big masses and a small mass. When you have one really big mass and a bunch of really small masses, then it becomes more stable. If I remember correctly he said that the million-year instability is caused by Ceres.

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Break out the game....

...of asteroids. It was a nice game that used stroke (x-y) generation for the images, not raster generated images. The effects were pretty nice.

From a galaxy far far away and a long time ago.

At least you didn't shoot down living objects (life forms). Pretty harmless.

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Boffin

Re: Break out the game....

Vector graphics is the term you're after

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> At least you didn't shoot down living objects (life forms). Pretty harmless.

The widows of countless UFO pilots beg to differ, you callous murdering speciesist!

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Anonymous Coward

yeah, well

if there was a big bang, the whole thing is a debris field anyway, so what does anyone expect? Of course we are going to get lambasted with space chunks. The main questions are, when, and how big? Not if.

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Re: yeah, well

The bits of debris are nothing to do directly with the Big Bang; they are the results of accretion of gas and dust from an earlier supernova.

And this article is saying exactly what you are saying, i.e. we are getting hit with bits of different sizes and we need to get a grip on exactly what is going on. Unlike previous societies where cities were few and independent and the population was widely dispersed, a strike on some of the big centres (London, New York, you name them) would cause widespread economic dislocation. It looks like this is a bigger risk than a nuclear exchange, so the money that went into MAD needs to go into understanding, and then finding ways to mitigate, what is a very real external threat.

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Re: yeah, well

Don't worry. Plenty of money will go into understanding, and then finding ways to mitigate, this very real external threat. It'll happen very quickly _after_ the first city gets levelled.

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Alien

Re: yeah, well

"Space Chunks", are they the same as the Pineapple variety?

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Re: yeah, well

Similar, only a lot more gritty and they'll do a real number on your teeth.

Personally I prefer Jaffas... :-)

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Re: yeah, well

"The bits of debris are nothing to do directly with the Big Bang"

If the causal connection can't be established, then how can we know with any certainty that the big bang occurred?

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Re: yeah, well - @David Pollard

You're looking at things on the wrong scale.

The evidence for the Big Bang lies in things like the cosmic background microwave radiation, and galactic red shift. If the laws of physics were slightly different, there could have been a Big Bang which did not result in star formation - except nobody would be around to observe it.

The evidence doesn't only come from very large scales - particle physics shows that, for the present range of known particles to exist, at some time the universe was very hot and dense (replace "very" with "inconceivably" for best effect.) That's because, if that wasn't the case, there would never have been a stage at which the necessary quark soup existed to crystallise out into hadrons as the universe cooled. It is exactly the same way that we can tell that certain rocks were once extremely hot, because of the way that they have crystallised.

From different ends, then, we know that at one time the universe was extremely small and hot, and that it is currently expanding; we can also detect the fossil radiation from the extremely hot stage. There are plenty of books which give a much, much fuller explanation, and I'm only posting this extremely superficial overview because without it you might not realise the kind of evidence they will be discussing, and how compelling it is.

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Re: yeah, well

If the causal connection can't be established, then how can we know with any certainty that the big bang occurred?

I don't even know that YOUR MOM occurred, so what are you on about?

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Holmes

Re: yeah, well

It'll happen very quickly _after_ the first city gets levelled.

That was the idea in "Rendezvous with Rama" where Italy gets righteously flattened from above.

But isn't there a risk that some automatic nuke launch system will be triggered, at which point the next asteroid is the least of our worries? Are these things off hairtrigger autoresponse? I am not sure...

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Coat

Re: yeah, well

"Space Chunks", are they the same as the Pineapple variety?

You're thinking of Solar Cubes...

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Maybe we need a couple hits near some major cities

Nothing like the risk of death at any time from space debris to get everyone to stop fighting over stupid and petty differences and work together to do something about this.

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Unhappy

Re: Maybe we need a couple hits near some major cities

"Maybe we need a couple hits near some major cities

Nothing like the risk of death at any time from space debris to get everyone to stop fighting over stupid and petty differences and work together to do something about this."

Apparently a kiloton-range object exploding above a city with a population of over a million people and injuring people simply wasn't close enough to move the 'something must be done' knee into jerking, so how near a near miss would be needed? Answer: a hit.

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Re: Maybe we need a couple hits near some major cities

Any hit with any human casualties, in a place that other folks can travel to, would be sufficient. Tunguska is too remote, in both space and time.

BTW a kiloton-equivalent object vaporising ten or more miles above the surface (ie Chelyabinsk) is no great deal. Lots of broken glass, but few severe injuries. It's anything that reaches (or comes very close to) the ground and creates a nuke-equivalent plasma ball there, which we have to be more concerned about.

The other danger, not mentioned above, is what might happen if a meteor strike devastated (say) Karachi. Would it be mis-identified, leading to an all-out nuclear strike and counterstrike in the following minutes? Indeed, are we sure that the USA or Russia would correctly identify what nature could throw at Washington or Moscow or other major cities?

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Anonymous Coward

Re: Maybe we need a couple hits near some major cities

"The other danger, not mentioned above, is what might happen if a meteor strike devastated (say) Karachi. Would it be mis-identified, leading to an all-out nuclear strike and counterstrike in the following minutes? Indeed, are we sure that the USA or Russia would correctly identify what nature could throw at Washington or Moscow or other major cities?"

Fortunately nuclear detonations have a very distinct 'double-flash' that asteroid strikes do not. The outer flash is caused by the air itself being superheated by the release of hard radiation, the second by the expansion of the actual fireball, composed of the physical material of the bomb itself. Although facts don't automatically prevent the human element of panic, confusion and impulsive decisions I suppose.

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Re: Maybe we need a couple hits near some major cities

IIRC it was the fact that some explosions in the Indian Ocean area exhibited the nuke double-flash that indicated that Apartheid-era South Africa was playing with nukes, either home-grown or borrowed from Israel.

And, oh, the possibility of a meteor strike causing a nuclear launch has been discussed, extensively, in fiction. For example, the late H. Beam Piper wrote a very long series of short stories and novels during the 1950s and early 1960s based on the notion of a Terran Federation, created by (mostly) people from the Southern Hemisphere after there was a short nuke war in the Northern Hemisphere. Early on he establishes that the primary cause of the war had been the total destruction of a town in the US, leading to an American strike against the USSR, leading to a Soviet counter-strike... and that, after the war, when some American and Soviet military and science types met in Argentina and tried to figure out who started the war both had lost, it becomes clear that the Soviets didn't launch first. Considerable further effort indicated that the first hit was due to a very large, very fast, extrasolar meteor. Oops. For another example, in Niven and Pournelle's _Lucifer's Hammer_ the Earth takes a serious hit from a very large comet (my fav scene: the Southern California surfer dude who rode the tsunami into downtown LA...) and that hit directly causes a nuclear war, as China observes that the Soviets are gonna get awfully chilly and that they are south of Sov-land and a lot warmer. The Indians and the Turks ain't too thrilled, either.

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Anonymous Coward

Re: Maybe we need a couple hits near some major cities

"IIRC it was the fact that some explosions in the Indian Ocean area exhibited the nuke double-flash that indicated that Apartheid-era South Africa was playing with nukes, either home-grown or borrowed from Israel."

That's right - the 'Vela Incident' in 1979, although no corroborating evidence was ever found.

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Alien

The odds are not too shabby

It's been estimated that the total urban area on Earth is around 3 million sq. km.

The Earth's surface area is ca. 150 million sq. km.

So the odds of hitting some urban area is about 1 in 50 or so.

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Re: The odds are not too shabby

Or at an average of one strike per year, two urban meteorites per century.

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Re: The odds are not too shabby

Two per century, eh? Well we have already had Chelyabinsk, so if NASA could just steer a meteorite onto a collision course with somewhere urban that we won't mind losing - I vote for Canberra - that will be our quota, and we can stop worrying until 2100...

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Re: The odds are not too shabby

I nominate Bilbyville.

(Unless Bilby lives in Queanbeyan.)

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Re: The odds are not too shabby @ Bilby

I think for Britain this would be Milton Keynes, or possibly Slough.

( One could argue for Central London on a busy day with parliament in full session. But while that would raise the average IQ of the nation by quite a bit, it would also destroy some beautiful Old Stuff that *would* be missed. )

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Re: The odds are not too shabby

Actually two per year, so four per century.

These are not even the big deal. They are the biggest deal we can look for because they recur on a period where we can look.

The big deal is that our sun is flying through a cloud of rocks that don't circle it. Most of the time it is less dense like now, but other times it is quite dense. In those times the speed of the worst possible sun-orbiting asteroid seems but a gentle kiss compared to an interstellar comet's smack. These threats don't recur, and there is no way to look for them. They will come, or not. The only way to deal with this threat is with distributed backups.

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Anonymous Coward

Re: The odds are not too shabby @ Bilby

With family in both North and South London, I'd have to vote for North Oxfordshire, specifically Witney. A direct strike on David Cameron's constituency would not only get a lot of attention, but it would take out his constituency office (the people who demanded police protection from the Bishop of Oxford and threatened a 12 year old kid with an armed police response.)

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Re: The odds are not too shabby

@Vegan

Earth's surface area is about 500e6 km^2. You have to count the sea as well!

https://www.google.com/search?q=earth%27s+surface+area

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Re: The odds are not too shabby @ Bilby

Come friendly asteroids, land on Milton Keynes?

Just doesn't quite have the same ring to it as bombing Slough. Although I'd argue for Slough, Milton Keynes, Luton and a good few other places as well.

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Anonymous Coward

Re: The odds are not too shabby @ Bilby

Bradford, Leicester, and the East End of London also spring to mind as highly desirable for large impacts.......

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Anonymous Coward

Re: The odds are not too shabby

Dear Glen.

Syndal Boys, like me, would pick Glen Waverley.

Just sayin'

Fight?

: )

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Mushroom

Re: The odds are not too shabby @ Bilby

Bradford, Leicester, and the East End of London also spring to mind as highly desirable for large impacts.......

You Brits, always thinking about yourselves. But thinking small. As a loyal American, I vote for Mississippi.

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Re: The odds are not too shabby @ Bilby

>>"I think for Britain this would be Milton Keynes, or possibly Slough."

Come friendly asteroids and fall on Slough,

It isn't fit for humans now... ?

EDIT: Huh, @Nick Ryan, beaten to it!

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Re: The odds are not too shabby

So in fact, instead of looking at 2 per century we're looking at one every 150 years or so. Given that modern civilisation has only been around for about 150 years (defining "modern" here as the invention of the electric telegraph and reliable railways), there is the depressing possibility that the reason that civilisation took so long to develop after the Roman era is that we've repeatedly been knocked back by environmental factors, that civilisation has got started in an unusually benign period, and that this isn't likely to continue for very long, whether due to climate change, giant volcanoes or meteor strike.

I'm feeling a bit Marvin this morning.

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Coat

Re: The odds are not too shabby

"The odds of hitting some urban area is about 1 in 50 or so."

But still they come...

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Re: The odds are not too shabby

That's the odds for hitting an urban area. It isn't the odds for hitting your urban area. Those odds are significantly longer.

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