It is informative, but there is one aspect that they omit from their analysis - the effect of device performance of the cost of the server farm needed to provide service.The whole analysis is based on the storage device cost only (there are good reasons for this, but limits the relevance of their analysis). If higher read rates of an SSD translate into higher server transaction rates then fewer servers are needed at possibily dramatic additional savings.
Here is a specific scenario to make this concrete.
You have a search engine application that accesses a relative static index (small parts refreshed daily maybe, all of it refreshed monthly). The ability to randomly read blocks determines how many queries per second your server can handle. The 17-fold speed advantage of the SSD over the Cheetah 15K is a huge win here. Of course you can set up a RAID 0+1 of Cheetah's but your server box only holds 4 data drives (out of 6, you mirror 2 more for redundant storage of the OS and application). So you need to buy four times as many servers using Cheetahs than SSDs, which use more than 4X the power and take up extra data center space (which is not free).
Or you could stuff a dozen or more Cheetahs into a RAID chassis that costs several times more than one server box.
Either way the cost of the Cheetahs themselves is trivial compared to the cost of the hardware required to actually make use of them.
Target is the only retailer that even lists Linux models on their website; they used to sell the 7" Eee PC in stores. Now they sell Windows models in-store & advertise them, as do all the other retail stores that sell computers.
This past week I looked at net books at my local Target and found only Linux models.
So, this is not universally true. At least, not yet.
... We have one (1) data point for solar flares of this magnitude. We cannot make *any* meaningful statements about frequency.
Not true. Even ZERO observations during a period of time provide information about frequency of occurrence: i.e. it sets a probabilistic lower bound on the frequency of the (hypothesized) event.
One observation during the less than 170 years when this could be detected gives this, roughly speaking, 10-1 odds against being an only one-in-1700 year event.
Might it be an only one-in-a-millenium event? Sure. But the odds are rather against that being the case.
On the other side... I am willing to bet that both US Navy and Russian Navy are sitting on a bunch of highly classified charts of significant chunks of the ocean floor for use on their subs.
You're absolutely right of course, they have detailed charts created using submarine differential gravitimeter data (submarines never turn on a sonar on patrol). But the data is generally only for submarine patrol areas and, as you say, highly classified and thus unavailable for most uses including most U.S. Navy uses. A separate public data set would still be highly valuable to many people.
You'd think the U.S. Navy would have some interest in having a good map of the ocean floor, and they certainly have the resources to do it.
A mapping project taking 10 years would cost $200 million a year, out of an annual budget of $130 billion. Heck, build a dedicated fleet of mapping ships with a service life of 25 years to do the job right (you'd only need 8) and drive the annual cost down to $80 million. It only has to be done once.
Next thing you know you're making the wages of an illegal immigrant farm worker.
And the reason that this does not actually happen in right-to-work states is?
Because the non-unionized auto makers must provide hourly wages equivalent to the UAW plants to keep the union out.
And they do pay the same (adjusted for cost of living). The legendary "UAW penalty" is due to the Big Three having been in business in the U.S. a long time and having a retired work force who has earned pensions and health care, the costs of which are then misleadingly folded in to the "hourly cost" per worker.
By being recent entries into the U.S., and through having hired a young labor force, the foreign factories avoid the cost of having retired workers to take care of (that, and the government subsidies they received from the states to locate there).
The UAW is being used to great extent as a whipping boy by the Red Staters who want all those jobs shipped down to Dixie, and by the management of the Big Three who want to admit no responsibility to the disaster they have brewed up.
The famous "UAW tax" (that oft stated $71/hr GM employee cost vs $47/hr for Toyota USA) is due to the existence of a retired work force that earned pensions and health during their decades on the job. The Japanese companies have lower costs because they are new kids on the block, have hired a young labor force, and have no pension obligations.
The real hourly wages of UAW line workers, vs Toyota USA workers, is virtually the same (and it is very likely that those un-unionized auto workers in the South have the UAW to thank for the good wages they receive - maintaining near parity is important for keeping the union out).
Those UAW pensions are earned property of the pensioners, same as any piece of real estate, or IRA, or any piece of "intellectual property."
That does not, of course, mean that this property won't be taken from them. Mismanaged companies do this to employees all the time (by failing and ruining everyone except upper management). And everyone who owns stock in any form has lost a lot of money in recent months. It is unlikely that UAW pensioners will escape from the economic mess whole, any more than will the rest of us.
Two of the companies that are complaining are Google and Microsoft, both of whom give good salaries and great benefits when compared with the average job.
Last I looked, Google has requirements that are considerably higher than and different from those for most companies -- they're one of the few actually looking for people with M.S. and Ph.D. CS degrees, for instance. Not surprising they have trouble finding people, given that.
Google's hiring problems are partly of their own making, even given their high standards.
The problem is that their hiring process is strongly biased in favor of rejecting applicants. The interview process is a day-long ordeal of one-on-one hour long interviews, one after another, with only a break for lunch. Every single interviewer has to approve you or you are out.
This rigorous process does ensure that only highly qualified people get through, but it also rejects the majority of highly qualified people. Seriously folks, how often do you do eight interviews in a row without a single problematic experience? How about doing a difficult white-board coding exercise without a muffing something up after seven hours of essentially non-stop grilling?
Google is not alone in hiring like this, some other large software corporations (Microsoft, Symantec, etc.) also believe that this is the best of all possible hiring processes.
The Sun alone can capture an interstellar interloper!
The Sun alone can't capture a 'stray' comet...
Although gravitational interaction with the gas giants would be the major way of losing enough kinetic energy to be captured, remember that hyperbolic comets make very close approaches to the Sun, and undergo intense heating. The out-gassing that creates the famous cometary tail creates measurable accelerations, and these would be quite significant for "fresh" comets (with lots of frozen gas) making close approaches.
Besides that, how would it have come here anyway? What is the escape velocity for getting out of a star system?
There is nothing mysterious or difficult to believe here.
We see about four comets per century that have hyperbolic trajectories - that is to say, they are never coming back.
These hyperbolic comets are either interstellar interlopers already and have not been captured by the solar system (which would typically occur by losing part of its kinetic energy to one of the gas giants through gravitational interaction), or they are solar system comets being ejected into interstellar space (through gaining energy by the same mechanism) to become future interlopers in other star systems. Either way, we see the effect of comet ejection regularly, every few decades.
Since the Oort Cloud is much denser with comets compared to the density of wandering comets in interstellar space, most hyperbolic comets are going to be the latter type.
Machholz 1, if it is alien, was captured by the solar system some time in the past. Although this type of capture may be rare, since it would be going on since the formation of the solar system a substantial population of alien comets should have built up by this time, and captured aliens may be a more common sight than one-shot hyperbolic visitors.
And abstract algebra has extremely powerful applications in computer science, in the study of algorithms.
Consider "path algebras" a formalization of graph theory algorithms. Graph theory problems, and the algorithms to solve them, can be described using abstract algebra.
New problems that you are interested in can be analyzed and described in this same way, and once you have done so you immediately find existing algorithms that can be applied directly, along with all of their theoretical analyses.
Anyone interested in developing algorithms should be familiar with this (although I suspect many are not).
See for example: Graphs and Networks by Bernard Carre (Oxford : Clarendon Press ; New York : Oxford University Press, 1979).
Right! Which is pre-cise-ly why mere hobbyists were totally unimportant when steam engines were superseded by explosion/electric engines, when electricity superseded town gas, or when heavier-than-air craft superseded dirigibles, or when modern biochemicals/genetics/pharmaceutics took off after the '70s. And to the whole transistor -> chip -> microcompting discontinuity thing.
This is a bit more like the amateur's role in the development of jet engine or fission reactor technology. That is to say, negligible or less.
Some technologies are out of the reach of the hobbyist - especially with regard to genuine innovation (as opposed to copying or simply using commercially available technologies on a small scale).
Note that even with the dominant role of hobbyists in the rise of the microcomputer they didn't develop the LSIC technology, nor make the chips they built their home brew computers from.
The Feds themselves (and, in fact, all other institutions that find themselves managing health and life) use a similar economic risk management approach. Corporations, and the government, use similar calculations for deciding what to spend on safety measures (there is a famous case of one such calculation in a memo surfacing in lawsuit over the Ford Pinto's fuel tank).
I only used the NPR link on the EPA life value calculation because it was recent and widely publicized and thus convenient.
Life valuations on the order of several million dollars are the rule in all forms of risk assessment (the EPA story was unusual only in that the reduction in value was anomalous, and on the low end).
While jury awards can be extremely high, far above the economically assessed value of life, such awards are actually quite rare and cannot be used to determine cost-benefit calculations any more than you can plan your family budget by assuming you'll win the lottery.
The expected ("average") number of people who might be exposed to hydrazine was around 0.035, the probability of anyone being exposed was about 0.01 (that is to say 1%), the risk of a fatality from exposure is considerably less than that (hydrazine is toxic, but it is nothing like a lethal war gas). The cost of the shoot-down though was 60 million dollars. If we suppose a fatality risk of 0.1% (i.e. in the case that someone is exposed there is an average fatality risk of 10%), then the cost per avoided fatality was something like 60 billion dollars.
Normally the economic value attached to a human life for planning purposes is several million dollars, the Bush Administration's EPA recently set its value at $6.9 million:
http://www.npr.org/templates/story/story.php?storyId=92470116)
Thus the shootdown hazard reduction decision seems out of line with government priorities to a tune of about 10,000 fold.
Why the shootdown? My guess is a combination of a live interceptor test, and destruction of highly classified technology.
Wow. Such a monstrous act is a shock to any normal person, but it makes sense that the "spam king" would turn out to be a genuine conscienceless sociopath.
You left off my favorite, the lowest setting: "tickle". It is the most versatile setting, being useful for ringing confessions out of prisoners, and for R&R (just don't hit that dial in the heat of the moment).
I can't tell if your comments are a joke or not...
We are talking about a passenger jet, not a fighter jet, right? You want to take a 747 and turn it upside down? You want to cause enough acceleration that the passengers will be incapacitated? Just how much accel. do you think a 747 can do??? Going from Mach 0.2 to 0.4 is no big deal. Again with the vertical climb, the passenger jet will stall if you were at an angle to make everybody fall to the rear...
The service (not ultimate) G-load limit on a commercial airliner is (FAA regulation) at least 2.5 g's, and could exceed 3.8 g's (the negative load has be at least -1.0 g's).
By making banking turns the pilot can keep the plane under +2.5 g's almost continually. Alternatively dives and climbs can switch back and forth between +2.5 and -1.0. Either way, the terrorists are not going to be running around in the aisles.
Before accepting the argument that we are imminently running out of a whole slew of elements, it would be nice to see a reasonably solid case presented for even one of them.
To the extent that this is even addressed, the articles make appeals to uncertainty - production figures are lacking and good estimates of reserves don't exist - then offer specific dates for running out, alluding to the USGS as providing the data used to make these claims. No explanation of how any of the calculations were done, nor an enumeration of the assumptions regarding supply on which they were based.
So lets pick one of the elements deemed most at risk, gallium say, nearly all of which is used in GaAs electronics.
The principal source of gallium is bauxite, a widely distributed ore of aluminium for which the reserves are immense.
Currently, less than 10% of the gallium in bauxite is extracted, apparently due to technology and cost considerations (that is, at current prices and with current technologies it isn't sufficiently profitable to do it).
Current refinery production is around 80 tons annually, substantial gallium is already recycled, but considerable growth in demand is expected.
The total world supply of gallium in mineable bauxite ore is estimated at (whether or not the gallium is considered recoverable) is estimated to exceed one million tons.
So: if extraction rates can rise to 10% then the world supply is really 100,000 tons. About a 1000 year supply at current usage rates. If we suppose that higher prices and more advanced technology can increase the extraction efficiency beyond this, then the supply is correspondingly increased.
Now there might be an impending imbalance in supply and demand if the total extraction rate by the aluminum industry is too low to match demand in the future. But this is quite different from "running out". Better extraction and more efficient use of gallium could redress it (both natural results of higher prices), and new technologies might largely supplant GaAs with superior products (quantum dot lasers, organic solar cells, anyone?). At some point recycling might take over as the principal supply (one of the reasons that iron production has flattened).
... The basic 5KT primer is big enough by itself but 5Kt isn't going to take out much more than a city block. What city do you live in?
The standard city block in Manhattan is 80 m x 274 m. The lethal radius of a 5 kt nuclear explosion is on the order of 1000 m (defined by the range at which 50% would die; many would be killed well beyond this range) so the lethal circle is something like 8 blocks by 24 blocks, encompassing roughly 160 blocks total.
This is quite a bit more than "a city block".
I am reminded of an article published in Analog around 1970 showing the exponential curve of the speed of human travel. It plotted very nicely: horse, locomotive, aeroplane, rocket. At the time human speed had recently hit a new high: the Apollo moon missions with humans traveling at 11.09 km/sec (Apollo 10 in 1969 was the fastest). The author projected we would be traveling close to the speed of light and be prepared to colonize the galaxy before 2000.
Almost 40 years later the fastest any human has ever travelled is (drum roll) 11.09 km/sec on Apollo 10. It looks like, with luck, humans may again travel about as fast in another 20 years.
Just to make something even clearer: you should read the article and learn something before recycling canned opinions.
An essential feature of solar thermal power is that it easily and efficiently stores solar energy directly as heat. From the article:
The key attribute of CSP is that it generates primary energy in the form of heat, which can be stored 20 to 100 times more cheaply than electricity -- and with far greater efficiency. Commercial projects have already demonstrated that CSP systems can store energy by heating oil or molten salt, which can retain the heat for hours. Ausra and other companies are working on storing the heat directly with water in the tubes, which would significantly lower cost and avoid the need for heat exchangers.
"Solar cannot replace Coal. It's completely unsuitable for supplying base-load power because it only works half the time (at best)."
Solar thermal power is perfectly capable of supplying base load, i.e. continuous, power and it is also the most attractive technology for large commercial solar power plants. See Solar Thermal Energy for a convenient introduction.
Solar thermal power uses concentrated solar light to heat a heat transfer fluid. The heat can be stored in a large insulated tank or other thermal mass very cheaply, with negligible energy loss. Averaging power output over the day-night cycle is fairly easy, and averaging over several days is also feasible.
Note also that all base load plants (coal, hydro, nuclear) are down part of the time for maintenance.
I wonder if the organizers of this study realize that, with a little recoding, they have a salable product on their hands: a flirting training tool for guy geeks!
In reading the study didn't you find yourself wanting to see those images of women signaling sexual interest versus those that were simply being friendly, to see if you too could tell the difference, and if not, to learn how? And now that I think of it, why isn't there a Flirting for Dummies book? This market seems ripe for exploitation (err... make that "development").
... what I loathed was having to almost learn Mandarin, or Hindi to understand my math teachers.
Worse still - learning Mandarin only to discover your professor actually spoke Cantonese, and learning Hindi only to find that the TA only spoke Tamil!
Slashdot Mirror
It is informative, but there is one aspect that they omit from their analysis - the effect of device performance of the cost of the server farm needed to provide service.The whole analysis is based on the storage device cost only (there are good reasons for this, but limits the relevance of their analysis). If higher read rates of an SSD translate into higher server transaction rates then fewer servers are needed at possibily dramatic additional savings.
Here is a specific scenario to make this concrete.
You have a search engine application that accesses a relative static index (small parts refreshed daily maybe, all of it refreshed monthly). The ability to randomly read blocks determines how many queries per second your server can handle. The 17-fold speed advantage of the SSD over the Cheetah 15K is a huge win here. Of course you can set up a RAID 0+1 of Cheetah's but your server box only holds 4 data drives (out of 6, you mirror 2 more for redundant storage of the OS and application). So you need to buy four times as many servers using Cheetahs than SSDs, which use more than 4X the power and take up extra data center space (which is not free).
Or you could stuff a dozen or more Cheetahs into a RAID chassis that costs several times more than one server box.
Either way the cost of the Cheetahs themselves is trivial compared to the cost of the hardware required to actually make use of them.
Target is the only retailer that even lists Linux models on their website; they used to sell the 7" Eee PC in stores. Now they sell Windows models in-store & advertise them, as do all the other retail stores that sell computers.
This past week I looked at net books at my local Target and found only Linux models.
So, this is not universally true. At least, not yet.
... We have one (1) data point for solar flares of this magnitude. We cannot make *any* meaningful statements about frequency.
Not true. Even ZERO observations during a period of time provide information about frequency of occurrence: i.e. it sets a probabilistic lower bound on the frequency of the (hypothesized) event.
One observation during the less than 170 years when this could be detected gives this, roughly speaking, 10-1 odds against being an only one-in-1700 year event.
Might it be an only one-in-a-millenium event? Sure. But the odds are rather against that being the case.
On the other side... I am willing to bet that both US Navy and Russian Navy are sitting on a bunch of highly classified charts of significant chunks of the ocean floor for use on their subs.
You're absolutely right of course, they have detailed charts created using submarine differential gravitimeter data (submarines never turn on a sonar on patrol). But the data is generally only for submarine patrol areas and, as you say, highly classified and thus unavailable for most uses including most U.S. Navy uses. A separate public data set would still be highly valuable to many people.
You'd think the U.S. Navy would have some interest in having a good map of the ocean floor, and they certainly have the resources to do it.
A mapping project taking 10 years would cost $200 million a year, out of an annual budget of $130 billion. Heck, build a dedicated fleet of mapping ships with a service life of 25 years to do the job right (you'd only need 8) and drive the annual cost down to $80 million. It only has to be done once.
Let me just say this about Anonymous Coward's post: "Hallelujah brother!"
This comment is absolutely dead on!
And the reason that this does not actually happen in right-to-work states is?
Because the non-unionized auto makers must provide hourly wages equivalent to the UAW plants to keep the union out.
And they do pay the same (adjusted for cost of living). The legendary "UAW penalty" is due to the Big Three having been in business in the U.S. a long time and having a retired work force who has earned pensions and health care, the costs of which are then misleadingly folded in to the "hourly cost" per worker.
By being recent entries into the U.S., and through having hired a young labor force, the foreign factories avoid the cost of having retired workers to take care of (that, and the government subsidies they received from the states to locate there).
The UAW is being used to great extent as a whipping boy by the Red Staters who want all those jobs shipped down to Dixie, and by the management of the Big Three who want to admit no responsibility to the disaster they have brewed up.
The famous "UAW tax" (that oft stated $71/hr GM employee cost vs $47/hr for Toyota USA) is due to the existence of a retired work force that earned pensions and health during their decades on the job. The Japanese companies have lower costs because they are new kids on the block, have hired a young labor force, and have no pension obligations.
The real hourly wages of UAW line workers, vs Toyota USA workers, is virtually the same (and it is very likely that those un-unionized auto workers in the South have the UAW to thank for the good wages they receive - maintaining near parity is important for keeping the union out).
Those UAW pensions are earned property of the pensioners, same as any piece of real estate, or IRA, or any piece of "intellectual property."
That does not, of course, mean that this property won't be taken from them. Mismanaged companies do this to employees all the time (by failing and ruining everyone except upper management). And everyone who owns stock in any form has lost a lot of money in recent months. It is unlikely that UAW pensioners will escape from the economic mess whole, any more than will the rest of us.
Last I looked, Google has requirements that are considerably higher than and different from those for most companies -- they're one of the few actually looking for people with M.S. and Ph.D. CS degrees, for instance. Not surprising they have trouble finding people, given that.
Google's hiring problems are partly of their own making, even given their high standards.
The problem is that their hiring process is strongly biased in favor of rejecting applicants. The interview process is a day-long ordeal of one-on-one hour long interviews, one after another, with only a break for lunch. Every single interviewer has to approve you or you are out.
This rigorous process does ensure that only highly qualified people get through, but it also rejects the majority of highly qualified people. Seriously folks, how often do you do eight interviews in a row without a single problematic experience? How about doing a difficult white-board coding exercise without a muffing something up after seven hours of essentially non-stop grilling?
Google is not alone in hiring like this, some other large software corporations (Microsoft, Symantec, etc.) also believe that this is the best of all possible hiring processes.
The Sun alone can capture an interstellar interloper!
The Sun alone can't capture a 'stray' comet...
Although gravitational interaction with the gas giants would be the major way of losing enough kinetic energy to be captured, remember that hyperbolic comets make very close approaches to the Sun, and undergo intense heating. The out-gassing that creates the famous cometary tail creates measurable accelerations, and these would be quite significant for "fresh" comets (with lots of frozen gas) making close approaches.
Besides that, how would it have come here anyway? What is the escape velocity for getting out of a star system?
There is nothing mysterious or difficult to believe here.
We see about four comets per century that have hyperbolic trajectories - that is to say, they are never coming back.
These hyperbolic comets are either interstellar interlopers already and have not been captured by the solar system (which would typically occur by losing part of its kinetic energy to one of the gas giants through gravitational interaction), or they are solar system comets being ejected into interstellar space (through gaining energy by the same mechanism) to become future interlopers in other star systems. Either way, we see the effect of comet ejection regularly, every few decades.
Since the Oort Cloud is much denser with comets compared to the density of wandering comets in interstellar space, most hyperbolic comets are going to be the latter type.
Machholz 1, if it is alien, was captured by the solar system some time in the past. Although this type of capture may be rare, since it would be going on since the formation of the solar system a substantial population of alien comets should have built up by this time, and captured aliens may be a more common sight than one-shot hyperbolic visitors.
And abstract algebra has extremely powerful applications in computer science, in the study of algorithms.
Consider "path algebras" a formalization of graph theory algorithms. Graph theory problems, and the algorithms to solve them, can be described using abstract algebra.
New problems that you are interested in can be analyzed and described in this same way, and once you have done so you immediately find existing algorithms that can be applied directly, along with all of their theoretical analyses.
Anyone interested in developing algorithms should be familiar with this (although I suspect many are not).
See for example:
Graphs and Networks by Bernard Carre (Oxford : Clarendon Press ; New York : Oxford University Press, 1979).
Right! Which is pre-cise-ly why mere hobbyists were totally unimportant when steam engines were superseded by explosion/electric engines, when electricity superseded town gas, or when heavier-than-air craft superseded dirigibles, or when modern biochemicals/genetics/pharmaceutics took off after the '70s. And to the whole transistor -> chip -> microcompting discontinuity thing.
This is a bit more like the amateur's role in the development of jet engine or fission reactor technology. That is to say, negligible or less.
Some technologies are out of the reach of the hobbyist - especially with regard to genuine innovation (as opposed to copying or simply using commercially available technologies on a small scale).
Note that even with the dominant role of hobbyists in the rise of the microcomputer they didn't develop the LSIC technology, nor make the chips they built their home brew computers from.
No, the premises aren't wrong.
The Feds themselves (and, in fact, all other institutions that find themselves managing health and life) use a similar economic risk management approach. Corporations, and the government, use similar calculations for deciding what to spend on safety measures (there is a famous case of one such calculation in a memo surfacing in lawsuit over the Ford Pinto's fuel tank).
I only used the NPR link on the EPA life value calculation because it was recent and widely publicized and thus convenient.
Life valuations on the order of several million dollars are the rule in all forms of risk assessment (the EPA story was unusual only in that the reduction in value was anomalous, and on the low end).
While jury awards can be extremely high, far above the economically assessed value of life, such awards are actually quite rare and cannot be used to determine cost-benefit calculations any more than you can plan your family budget by assuming you'll win the lottery.
For a good discussion of the risk magnitude of the re-entry of USA-193 read the comments on this blog:
http://www.armscontrolwonk.com/1797/usa-193-risk-calculation
The expected ("average") number of people who might be exposed to hydrazine was around 0.035, the probability of anyone being exposed was about 0.01 (that is to say 1%), the risk of a fatality from exposure is considerably less than that (hydrazine is toxic, but it is nothing like a lethal war gas). The cost of the shoot-down though was 60 million dollars. If we suppose a fatality risk of 0.1% (i.e. in the case that someone is exposed there is an average fatality risk of 10%), then the cost per avoided fatality was something like 60 billion dollars. Normally the economic value attached to a human life for planning purposes is several million dollars, the Bush Administration's EPA recently set its value at $6.9 million: http://www.npr.org/templates/story/story.php?storyId=92470116) Thus the shootdown hazard reduction decision seems out of line with government priorities to a tune of about 10,000 fold.
Why the shootdown? My guess is a combination of a live interceptor test, and destruction of highly classified technology.
Wow. Such a monstrous act is a shock to any normal person, but it makes sense that the "spam king" would turn out to be a genuine conscienceless sociopath.
You left off my favorite, the lowest setting: "tickle". It is the most versatile setting, being useful for ringing confessions out of prisoners, and for R&R (just don't hit that dial in the heat of the moment).
I can't tell if your comments are a joke or not...
We are talking about a passenger jet, not a fighter jet, right? You want to take a 747 and turn it upside down? You want to cause enough acceleration that the passengers will be incapacitated? Just how much accel. do you think a 747 can do??? Going from Mach 0.2 to 0.4 is no big deal. Again with the vertical climb, the passenger jet will stall if you were at an angle to make everybody fall to the rear...
The service (not ultimate) G-load limit on a commercial airliner is (FAA regulation) at least 2.5 g's, and could exceed 3.8 g's (the negative load has be at least -1.0 g's).
See: http://adg.stanford.edu/aa241/structures/FAR301.html (scroll down to Sec. 25.337 Limit maneuvering load factors).
By making banking turns the pilot can keep the plane under +2.5 g's almost continually. Alternatively dives and climbs can switch back and forth between +2.5 and -1.0. Either way, the terrorists are not going to be running around in the aisles.
Before accepting the argument that we are imminently running out of a whole slew of elements, it would be nice to see a reasonably solid case presented for even one of them.
Looking around for a source that actually makes a case for running out of any of these elements what I came up with are references to New Scientist articles that do nothing of the sort: http://www.idtechex.com/products/en/articles/00000591.asp
and
http://www.science.org.au/nova/newscientist/027ns_005.htm
To the extent that this is even addressed, the articles make appeals to uncertainty - production figures are lacking and good estimates of reserves don't exist - then offer specific dates for running out, alluding to the USGS as providing the data used to make these claims. No explanation of how any of the calculations were done, nor an enumeration of the assumptions regarding supply on which they were based.
So lets pick one of the elements deemed most at risk, gallium say, nearly all of which is used in GaAs electronics.
Actually reading the relevant USGA report: http://minerals.usgs.gov/minerals/pubs/commodity/gallium/mcs-2008-galli.pdf and also consulting this industry paper (gallium is discussed near the end): http://www.indium.com/_dynamo/download.php?docid=552
we learn the following.
So: if extraction rates can rise to 10% then the world supply is really 100,000 tons. About a 1000 year supply at current usage rates. If we suppose that higher prices and more advanced technology can increase the extraction efficiency beyond this, then the supply is correspondingly increased.
Now there might be an impending imbalance in supply and demand if the total extraction rate by the aluminum industry is too low to match demand in the future. But this is quite different from "running out". Better extraction and more efficient use of gallium could redress it (both natural results of higher prices), and new technologies might largely supplant GaAs with superior products (quantum dot lasers, organic solar cells, anyone?). At some point recycling might take over as the principal supply (one of the reasons that iron production has flattened).
... The basic 5KT primer is big enough by itself but 5Kt isn't going to take out much more than a city block. What city do you live in? The standard city block in Manhattan is 80 m x 274 m. The lethal radius of a 5 kt nuclear explosion is on the order of 1000 m (defined by the range at which 50% would die; many would be killed well beyond this range) so the lethal circle is something like 8 blocks by 24 blocks, encompassing roughly 160 blocks total. This is quite a bit more than "a city block".I am reminded of an article published in Analog around 1970 showing the exponential curve of the speed of human travel. It plotted very nicely: horse, locomotive, aeroplane, rocket. At the time human speed had recently hit a new high: the Apollo moon missions with humans traveling at 11.09 km/sec (Apollo 10 in 1969 was the fastest). The author projected we would be traveling close to the speed of light and be prepared to colonize the galaxy before 2000.
Almost 40 years later the fastest any human has ever travelled is (drum roll) 11.09 km/sec on Apollo 10. It looks like, with luck, humans may again travel about as fast in another 20 years.
Just to make something even clearer: you should read the article and learn something before recycling canned opinions.
An essential feature of solar thermal power is that it easily and efficiently stores solar energy directly as heat. From the article:
"Solar cannot replace Coal. It's completely unsuitable for supplying base-load power because it only works half the time (at best)."
Solar thermal power is perfectly capable of supplying base load, i.e. continuous, power and it is also the most attractive technology for large commercial solar power plants. See Solar Thermal Energy for a convenient introduction.
Solar thermal power uses concentrated solar light to heat a heat transfer fluid. The heat can be stored in a large insulated tank or other thermal mass very cheaply, with negligible energy loss. Averaging power output over the day-night cycle is fairly easy, and averaging over several days is also feasible.
Note also that all base load plants (coal, hydro, nuclear) are down part of the time for maintenance.
I wonder if the organizers of this study realize that, with a little recoding, they have a salable product on their hands: a flirting training tool for guy geeks!
In reading the study didn't you find yourself wanting to see those images of women signaling sexual interest versus those that were simply being friendly, to see if you too could tell the difference, and if not, to learn how? And now that I think of it, why isn't there a Flirting for Dummies book? This market seems ripe for exploitation (err... make that "development").
Worse still - learning Mandarin only to discover your professor actually spoke Cantonese, and learning Hindi only to find that the TA only spoke Tamil!