When the Associated Press releases a one-liner of some factoid, you're better of being critical. A 10ton object travelling at 15km/s doesn't have enough energy (about 0.3kt of TNT equivalent) to create a shockwave at more than 10km altitude that can destroy windows and blow out doors on the ground.
The Halifax explosion had ten times as much energy, that was released in much denser atmosphere, at one point and not along a track of at about 20km length. This just about managed to do similar damage at a distance of 16km. (Which is similar to the situation in Russia, where damage didn't just occur directly under the track of the asteroid.)
Given the much thinner atmosphere at this height and the fact that it was spread over such a long distance, it must have released more energy than the Halifax explosion. Anything less than 100ton mass is bogus, my guess is around 300-500 tons. (N.B.: my estimate at the time was made assuming a velocity of 10km/s, guessing up to 1000 tons.)
The size of the debris is quite well known - less than the original asteroid. Reducing the size of the debris to half that of the original asteroid (5m instead of 10m), would have prevented damage on the ground - by having less mass (and thus energy) to begin with and by breaking up higher in the atmosphere, giving more distance and thinner air to propagate the shockwave. The trajectory will also follow the laws of physics - conservation of momentum most notably. The largest pieces would have the least change in their trajectories.
Why several days? Because a large object will be brighter than 2008 TC3. Twice the diameter means twice the distance at which you could find it. But discovery is limited mainly by instument availability. You can't find something if you can't look for it. The more often you survey the sky, the earlier you'll find a new object once it is bright enough. Seriously large objects like the Tunguska meteorite (about 60m) or 2012 DA14 could be found at least weeks ahead of time - in the case of 2012 DA-14 more than a year.
No, the world surely would not have ended. We know for a fact that meteorite impacts have been observed by satellites designed to warn against nuclear weapons. The first few scared the shit out of operators, because the energy released by such meteorites is on the order of several kilotons. But neither Russians nor Americans were stupid.
The meteorite was several times larger than the last (and first ever) predicted impact in 2008.
It is trivially possible these days, to do several complete surveys of the sky each day and ensure that such asteroids are discovered several days ahead of time. Computers allow us do evaluate the data more or less in real time. The problem is: You need funding for the telescopes around the world and staff to run them.
While all the observatories would do, is to give warning to people in the area to stay indoors and away from windows - or leave the area alltogether if the rock is a bit larger - that's still better than "oups" and a couple videos from dashboard cameras. It would also provide a viable basis for sending up a rocket with a few tons of mass to break up an asteroid into harmless chunks. Possibly a combination of high and low density materials, like concrete and lead, to achieve a good distribution of the momentum through the whole asteroid.
I'm not kidding. A single ton mass in a head-on collision with 10-15km/s has as much kinetic energy as 15-30 tons of high explosives. Which should be enough to break up a 30m asteroid into very small chunks (this one in russia was probably around 10m), although some preparation is certainly in order.
The point of a two player game, like Go, is to beat the opponent. If you know your opponent doesn't like a certain kind of opening, or is likely to feel overconfident in certain positions, thus creating weaknesses for you to exploit - this is a viable strategy, provided it works.
However, the better the players the more they look down upon such things - and rightfully so - because they learned the hard way that weak moves will be punished by good players.
Yeah right. Amurricans are the best people in the world and if anybody else is simply doing things better, this is clearly just a figment of people's imagination, because the USA is the best country in the world.
Living in Eastern Germany, this sounds oddly familiar.
It's not exactly about enlightenment, it is about the ideologies themselves. Every ideology needs a mechanism to stay coherent - if there is a group of people sharing thoughts without enforcing certain ideas and suppressing doubt, they simply won't have anything resembling what we call an ideology - because they all have different ideas and what we call an ideology is a group of people shareing the same kinds of ideas...
I've tried to put together my thoughts on this elsewhere.
There is one difference ever since the price of oil approached and then surpassed (for some time) $100 per barrel after 2005 or so: those claims are backed up with money for the first time since the end of the the Soviet Union.
The last iceage covered all of Northern Europe, Britain, parts of Germany, parts of Poland in massive, greenland-like glaciers and changed the climate massively all the way down to Africa. The alps too, were covered glaciers running all the way down into the surrounding areas, which were what you would call a tundra.
That was 20.000 years ago not millions of years.
Nature adapts - quickly. Much more quickly than anybody is giving her credit for.
Sardines had hundreds of millions of years to extent their range into freshwater, yet they didn't. It was only when a swarm of sardines got trapped in what is today Lake Taal, which used to be just another part of the Pacific Ocean. It became a lake only in the 1750ies, when a volcanic eruption cut it off from the ocean and rain turned saltwater into freshwater in a matter of decades.
Those decades were sufficient to do what hundreds of millions of years had not managed to do, because it had never been necessary. In 100,000 years, all evidence of happened in lake taal will have been erazed by the same geologic processes that gave rise to all of that in the first place.
The assumed stagnation and lethargy of the evolution of species is an artifact of processes that conserve their traces now accessible to us. Unless a species is pervasive and somehow amenable to be conserved over geologic time spans within the environment they live in, it will irrecoverably be lost to history.
Our biosphere survived several ICE AGES. Looking out of the window I see landscape that was covered with hundreds of meters of ice a (geologically) very short time ago and has undergone numerous radical climate changes, yet, failed completely to become a dead wasteland for any appreciable time once the ice retreated.
I've criticized more than once that Japanese law doesn't require sufficient redundancy, nor did the containment designs of the 1960ies provide it. It just so happens that the Mark II containment provided more redundancy by its flawed default design - which was sufficient in 6 out of 6 cases. Whereas the Mark I containment didn't have enough redundancy by its even more flawed default design in 5 out of 5 cases to survive the tsunami. Current technology would be a Mark IV or Mark V containment (ABWR or ESBWR respectively), if they hadn't stopped numbering them after Mark III.
For illustration: German law requires (at least since the early 1990ies, probably earlier) an analysis of possible damaging events to be made for each location of every nuclear power plant and that even under once-in-10.000-years-conditions (which don't include tsunamis for obvious reasons, but do include earthquakes, floods and others) there must be at least 2 emergency generators available, with the assumption that one generator is shut down for maintenance at the time and another one fails. That alone requires at least 4 generators at all times, even without any damaging event.
If the analysis shows that some generators are likely to be compromised by the event, you will need to add more, such that there will always be at least two working generators available (despite maintenance and an assumed failure) despite the event.
Wrong. Units 7 and 8 had not been build. Unit 5 and 6 were offline for refuelling. Unit 6 was the only one having a surviving emergency diesel generator. Which wasn't luck. It was a Mark II containment, the same that was used in all four reactors of Fukushima Daini (all with the same generator surviving the tsunami) and the single reactor in Tokai (dito).
Except that the WASH-1400 report, pubished in 1975, stated specifically that the containments of the BWR reactors (the Mark I containment was the only BWR containment back then) were not equipped to deal with a meltdown and would emit orders of magnitudes more radioactive material than PWR containments, such as Three Mile Island.
And that was just a report summerizing previously known facts - including tsunamis being a clear and present danger to nuclear power plants (although, at the time, not the in the US).
Furthermore, the area is not uninhabitable, but closed off by police. According to the BEIR VII report on the effects of low level radiation, it is expected that a long-term dose of 1000mSv would add 2-4% to the expected cancer mortality of the population of 24% on average for the US. (about 22% for Japan) A dose of 1000mSv can only be expected in the most contaminated areas (on the order of 40mSv/a as of last year) assuming total neglegt of any decontamination efforts. (Please bear in mind that half of this is the result of Cs-134, with a half-life of only 2 years.)
Even within the US there are larger differences than those. The 10th highest mortality rate for the US is in Delaware at about 26%. The 10th lowest is South Dakota with about 22.5%. (Source1)
Unless there are any moves to rapidly evacuate the population of Delaware and the other 9 states having even higher cancer mortality, I would suggest that "uninhabitable" is a misnomer.
Then, it's climate, not weather. Otherwise somebody would have to take responsibility and what self-respecting politician would do that?
No matter how many decades engineers say that the levees in New Orleans are perfectly insufficient for a city in that place, it's still climate change when the inevitable happens. When hurricane Irene came to New York last year, the models of the expected flooding were right at everybodies hands - because it happened before. Several times.
Nobody asked the obvious question: Why hasn't anybody done anything about it, since everybody seems to know about it?
So, you came up with a model that accurately predicts the past?
What nonesense is that? The accuracy of a model can only be determined by testing it against reality, and not against the data it has been fitted to. You need new data to do that and I'm sorry to tell you that new annual data sets will arrive only at a pace of one per year.
Meanwhile, shut up and look at the models you've made so far and be ashamed of the constant revisions in both directions.
In any other branch of science coming up with the kind of models and inaccuracies that climate science comes up with, scientists would simply say.. well, sorry, we cannot model these processes with any degree of accuracy and be done with it. If you came up with a better model, well, good for you, but now you have to *prove* it is actually better than all the rest so far.
There is no heat that could cause a meltdown in the first place. The reactor will not have run for any significant amount of time at any significant enough power level to release enough heat to melt anything that isn't made of butter... and even that might be a close call that depends on outside temperatures.
The fuel rods will consist mostly of U-235, which is much less radioactive than the Pu-238 that is commonly used and doesn't release any heat by itself. The radioactivity only comes into play once the reactor has been started up. But hopefully that will only happen after the probe is on its way away from earth.
No, it tells you just how fucked up the Soviet Union was after it fell apart. Hint: life expectancy dropped to levels not seen since the Stalin era, some 3 million people starved, froze to death or died for lack of access to medical care. Russia declared bankruptcy a mere 7 years later and neither Belarus nor Ukraine fared any better. Unlike Russia, they didn't have any resources to export, but instead were dependent on Russia for theirs.
The fact they are still working on the reactor is a result of the fact that Ukraine couldn't muster the $1bn to build the new shelter itself at any earlier time.
The Rwandan genocide was conducted with a few container loads of cheap Chinese machetes, clearly, we must ban the production of steel and any material that can be made to have a sharp edge.
Most explosives contain nitrogen compounds that can be made in fertilizer production. Explosives and fireguns are the main weapon of choice in conflicts all over the world, killing hundreds of thousands each year. Clearly, we cannot allow the pest of nitrogen fertilizer factories to spread over the planet. The naysayers who claim they are needed for food production are just lackeys of the weapon industry.
Cars kill 1.3 million people worldwide each year. Clearly, this technology must be banned.
Also, last time I looked, I couldn't find the place where the Soviet Union let East Germans mine one of the worlds largest uranium deposits, even though I knew where to look for it, since I wasn't born very far from it. They mined enough Uranium to generate 1000GW of power for 250years using unmoderated reactors.
A lignite stripmine, generating about one GW for about 30-40 years, on the other hand, is impossible to miss - it is larger than the town I was born in.
This isn't about risk. This is about destroying the landscape to generate power. This used to be a good idea, because it left at least some of the forests intact as a substitute for burning wood and charcoal.
But these days, it is all about people having no clue about nuclear power, being afraid of it, being unwilling to learn anything about it and continuing to be clueless and pissing their pants.
Slashdot Mirror
When the Associated Press releases a one-liner of some factoid, you're better of being critical. A 10ton object travelling at 15km/s doesn't have enough energy (about 0.3kt of TNT equivalent) to create a shockwave at more than 10km altitude that can destroy windows and blow out doors on the ground.
The Halifax explosion had ten times as much energy, that was released in much denser atmosphere, at one point and not along a track of at about 20km length. This just about managed to do similar damage at a distance of 16km. (Which is similar to the situation in Russia, where damage didn't just occur directly under the track of the asteroid.)
Given the much thinner atmosphere at this height and the fact that it was spread over such a long distance, it must have released more energy than the Halifax explosion. Anything less than 100ton mass is bogus, my guess is around 300-500 tons. (N.B.: my estimate at the time was made assuming a velocity of 10km/s, guessing up to 1000 tons.)
The size of the debris is quite well known - less than the original asteroid. Reducing the size of the debris to half that of the original asteroid (5m instead of 10m), would have prevented damage on the ground - by having less mass (and thus energy) to begin with and by breaking up higher in the atmosphere, giving more distance and thinner air to propagate the shockwave. The trajectory will also follow the laws of physics - conservation of momentum most notably. The largest pieces would have the least change in their trajectories.
Why several days? Because a large object will be brighter than 2008 TC3. Twice the diameter means twice the distance at which you could find it. But discovery is limited mainly by instument availability. You can't find something if you can't look for it. The more often you survey the sky, the earlier you'll find a new object once it is bright enough. Seriously large objects like the Tunguska meteorite (about 60m) or 2012 DA14 could be found at least weeks ahead of time - in the case of 2012 DA-14 more than a year.
Real live has radar.
And real live Americans and Chinese have shot down satellites using ballistic missles - delta v about 8km/s, accuracy had to be at least ~1-2m.
No, the world surely would not have ended. We know for a fact that meteorite impacts have been observed by satellites designed to warn against nuclear weapons. The first few scared the shit out of operators, because the energy released by such meteorites is on the order of several kilotons. But neither Russians nor Americans were stupid.
The meteorite was several times larger than the last (and first ever) predicted impact in 2008.
It is trivially possible these days, to do several complete surveys of the sky each day and ensure that such asteroids are discovered several days ahead of time. Computers allow us do evaluate the data more or less in real time. The problem is: You need funding for the telescopes around the world and staff to run them.
While all the observatories would do, is to give warning to people in the area to stay indoors and away from windows - or leave the area alltogether if the rock is a bit larger - that's still better than "oups" and a couple videos from dashboard cameras. It would also provide a viable basis for sending up a rocket with a few tons of mass to break up an asteroid into harmless chunks. Possibly a combination of high and low density materials, like concrete and lead, to achieve a good distribution of the momentum through the whole asteroid.
I'm not kidding. A single ton mass in a head-on collision with 10-15km/s has as much kinetic energy as 15-30 tons of high explosives. Which should be enough to break up a 30m asteroid into very small chunks (this one in russia was probably around 10m), although some preparation is certainly in order.
"Iran terrorizes own population with helicopters".
The point of a two player game, like Go, is to beat the opponent. If you know your opponent doesn't like a certain kind of opening, or is likely to feel overconfident in certain positions, thus creating weaknesses for you to exploit - this is a viable strategy, provided it works.
However, the better the players the more they look down upon such things - and rightfully so - because they learned the hard way that weak moves will be punished by good players.
Yeah right. Amurricans are the best people in the world and if anybody else is simply doing things better, this is clearly just a figment of people's imagination, because the USA is the best country in the world.
Living in Eastern Germany, this sounds oddly familiar.
It's not exactly about enlightenment, it is about the ideologies themselves. Every ideology needs a mechanism to stay coherent - if there is a group of people sharing thoughts without enforcing certain ideas and suppressing doubt, they simply won't have anything resembling what we call an ideology - because they all have different ideas and what we call an ideology is a group of people shareing the same kinds of ideas ...
I've tried to put together my thoughts on this elsewhere.
There is one difference ever since the price of oil approached and then surpassed (for some time) $100 per barrel after 2005 or so: those claims are backed up with money for the first time since the end of the the Soviet Union.
The last iceage covered all of Northern Europe, Britain, parts of Germany, parts of Poland in massive, greenland-like glaciers and changed the climate massively all the way down to Africa. The alps too, were covered glaciers running all the way down into the surrounding areas, which were what you would call a tundra.
That was 20.000 years ago not millions of years.
Nature adapts - quickly. Much more quickly than anybody is giving her credit for.
Lack of necessity.
Sardines had hundreds of millions of years to extent their range into freshwater, yet they didn't. It was only when a swarm of sardines got trapped in what is today Lake Taal, which used to be just another part of the Pacific Ocean. It became a lake only in the 1750ies, when a volcanic eruption cut it off from the ocean and rain turned saltwater into freshwater in a matter of decades.
Those decades were sufficient to do what hundreds of millions of years had not managed to do, because it had never been necessary. In 100,000 years, all evidence of happened in lake taal will have been erazed by the same geologic processes that gave rise to all of that in the first place.
The assumed stagnation and lethargy of the evolution of species is an artifact of processes that conserve their traces now accessible to us. Unless a species is pervasive and somehow amenable to be conserved over geologic time spans within the environment they live in, it will irrecoverably be lost to history.
Our biosphere survived several ICE AGES. Looking out of the window I see landscape that was covered with hundreds of meters of ice a (geologically) very short time ago and has undergone numerous radical climate changes, yet, failed completely to become a dead wasteland for any appreciable time once the ice retreated.
I've criticized more than once that Japanese law doesn't require sufficient redundancy, nor did the containment designs of the 1960ies provide it. It just so happens that the Mark II containment provided more redundancy by its flawed default design - which was sufficient in 6 out of 6 cases. Whereas the Mark I containment didn't have enough redundancy by its even more flawed default design in 5 out of 5 cases to survive the tsunami. Current technology would be a Mark IV or Mark V containment (ABWR or ESBWR respectively), if they hadn't stopped numbering them after Mark III.
For illustration: German law requires (at least since the early 1990ies, probably earlier) an analysis of possible damaging events to be made for each location of every nuclear power plant and that even under once-in-10.000-years-conditions (which don't include tsunamis for obvious reasons, but do include earthquakes, floods and others) there must be at least 2 emergency generators available, with the assumption that one generator is shut down for maintenance at the time and another one fails. That alone requires at least 4 generators at all times, even without any damaging event.
If the analysis shows that some generators are likely to be compromised by the event, you will need to add more, such that there will always be at least two working generators available (despite maintenance and an assumed failure) despite the event.
Wrong. Units 7 and 8 had not been build. Unit 5 and 6 were offline for refuelling. Unit 6 was the only one having a surviving emergency diesel generator. Which wasn't luck. It was a Mark II containment, the same that was used in all four reactors of Fukushima Daini (all with the same generator surviving the tsunami) and the single reactor in Tokai (dito).
Except that the WASH-1400 report, pubished in 1975, stated specifically that the containments of the BWR reactors (the Mark I containment was the only BWR containment back then) were not equipped to deal with a meltdown and would emit orders of magnitudes more radioactive material than PWR containments, such as Three Mile Island.
And that was just a report summerizing previously known facts - including tsunamis being a clear and present danger to nuclear power plants (although, at the time, not the in the US).
Furthermore, the area is not uninhabitable, but closed off by police. According to the BEIR VII report on the effects of low level radiation, it is expected that a long-term dose of 1000mSv would add 2-4% to the expected cancer mortality of the population of 24% on average for the US. (about 22% for Japan) A dose of 1000mSv can only be expected in the most contaminated areas (on the order of 40mSv/a as of last year) assuming total neglegt of any decontamination efforts. (Please bear in mind that half of this is the result of Cs-134, with a half-life of only 2 years.)
Even within the US there are larger differences than those. The 10th highest mortality rate for the US is in Delaware at about 26%. The 10th lowest is South Dakota with about 22.5%. (Source1 )
Unless there are any moves to rapidly evacuate the population of Delaware and the other 9 states having even higher cancer mortality, I would suggest that "uninhabitable" is a misnomer.
I don't know if you meant New Orleans or New York but you're wrong either way.
Then, it's climate, not weather. Otherwise somebody would have to take responsibility and what self-respecting politician would do that?
No matter how many decades engineers say that the levees in New Orleans are perfectly insufficient for a city in that place, it's still climate change when the inevitable happens. When hurricane Irene came to New York last year, the models of the expected flooding were right at everybodies hands - because it happened before. Several times.
Nobody asked the obvious question: Why hasn't anybody done anything about it, since everybody seems to know about it?
So, you came up with a model that accurately predicts the past?
What nonesense is that? The accuracy of a model can only be determined by testing it against reality, and not against the data it has been fitted to. You need new data to do that and I'm sorry to tell you that new annual data sets will arrive only at a pace of one per year.
Meanwhile, shut up and look at the models you've made so far and be ashamed of the constant revisions in both directions.
In any other branch of science coming up with the kind of models and inaccuracies that climate science comes up with, scientists would simply say .. well, sorry, we cannot model these processes with any degree of accuracy and be done with it. If you came up with a better model, well, good for you, but now you have to *prove* it is actually better than all the rest so far.
There is no heat that could cause a meltdown in the first place. The reactor will not have run for any significant amount of time at any significant enough power level to release enough heat to melt anything that isn't made of butter ... and even that might be a close call that depends on outside temperatures.
The fuel rods will consist mostly of U-235, which is much less radioactive than the Pu-238 that is commonly used and doesn't release any heat by itself. The radioactivity only comes into play once the reactor has been started up. But hopefully that will only happen after the probe is on its way away from earth.
No, it tells you just how fucked up the Soviet Union was after it fell apart. Hint: life expectancy dropped to levels not seen since the Stalin era, some 3 million people starved, froze to death or died for lack of access to medical care. Russia declared bankruptcy a mere 7 years later and neither Belarus nor Ukraine fared any better. Unlike Russia, they didn't have any resources to export, but instead were dependent on Russia for theirs.
The fact they are still working on the reactor is a result of the fact that Ukraine couldn't muster the $1bn to build the new shelter itself at any earlier time.
The Rwandan genocide was conducted with a few container loads of cheap Chinese machetes, clearly, we must ban the production of steel and any material that can be made to have a sharp edge.
Most explosives contain nitrogen compounds that can be made in fertilizer production. Explosives and fireguns are the main weapon of choice in conflicts all over the world, killing hundreds of thousands each year. Clearly, we cannot allow the pest of nitrogen fertilizer factories to spread over the planet. The naysayers who claim they are needed for food production are just lackeys of the weapon industry.
Cars kill 1.3 million people worldwide each year. Clearly, this technology must be banned.
You have no sense of proportion.
You do realize what you're talking about, huh?
And this is what slashdot calls informative these days. ;)
Mining isn't risk, mining is mining.
Also, last time I looked, I couldn't find the place where the Soviet Union let East Germans mine one of the worlds largest uranium deposits, even though I knew where to look for it, since I wasn't born very far from it. They mined enough Uranium to generate 1000GW of power for 250years using unmoderated reactors.
A lignite stripmine, generating about one GW for about 30-40 years, on the other hand, is impossible to miss - it is larger than the town I was born in.
This isn't about risk. This is about destroying the landscape to generate power. This used to be a good idea, because it left at least some of the forests intact as a substitute for burning wood and charcoal.
But these days, it is all about people having no clue about nuclear power, being afraid of it, being unwilling to learn anything about it and continuing to be clueless and pissing their pants.
Coal mining destroys landscapes forever - I've been living near strip mines all my life.