First, note that all we have so far is an allegation. Although we tend to like SpaceX around here, Valador are currently only accused scum, not confirmed scum.
Second, the alleged defamation occurred on June 8 2011. courthousenews.com reports on the suit on June 16. So that is offence to suit in about a week!
Moreover, neutrino astronomy is pretty much the only thing that can give us warning (albeit only a few hours) if a nasty supernova happens in our vicinity
There are no candidate supernovae progenitors close enough to us to be dangerous. (I can't remember what the lethal radius is, but it is not terribly large.)
I once tried to find the nearest possible supernova progenitor, and the best I could find was gamma velorum A, at 260 parsecs away, but I didn't spend a long time on this. (I might have been only looking for type II progenitors.)
More info here, which mentions a danger radius of about 25 light years for a type II supernova.
In the last few years I have been at three universities, two in Australia, I have used Unix, and had support. However, I've never tried to use wireless, and in all cases I was using deparmental IT people rather than university central IT people.
OK, I've done some cursory research (abstracts and intros of a few papers.) I didn't find a review, however it seems that there has been quite a bit written about such angular momentum transfers, and the age-rotational period-mass relationship for stars. (So this result is a step in an already developed field, not a breakthrough.) There was mention of interactions with a magnetized solar wind (i.e. a combination of my points 3 and 4 above) and also something called the Tayler-Spruit dynamo, which I think is about angular momentum transport between the star's core and envelope. For a young star, you'd expect the core to rotate faster than the envelope (conservation of angular momentum during the contraction) but the sun rotates like a solid body - same rotation period for all depths (or as far as we can probe by helioseismology.) The Tayler-Spruit appears to be a possible explanation for how a middle aged star like the sun can rotate like a solid body.
I'm happy enough with the idea that a star's mass determines its initial angular momentum (or, more likely, vice versa.) While not obviously true, it is certainly plausible. But once its angular momentum is set, how can it slow down? Here are all the possibilities I can think of: * It expands (radius increases) and so it can spin slower for the same angular momentum. However, this would be very uninteresting - if we have luminosity and temperature, we already know the radius. Adding an extra measurement which correlates with radius would give us no new information. Also, main sequence stars change their radius very slowly. (But I'm not so sure about very young MS stars.) * It redistributes its angular momentum from its envelope (which we observe) to its core. But this is the reverse of what I'd expect - the core would spin faster than the envelope, so any coupling between them would (rotationally) accelerate the envelope at the expense of the core. * It sheds angular momentum via its stellar wind. But main sequence stars shed very little mass in their winds. (From memory, for the sun it is on the order of 10^-14 solar masses per year.) Even if some strange effect caused the wind to be expelled in the best direction for shedding angular momentum, I don't think this could give any appreciable slowdown. (Again, I'm not sure about very young stars.) * It sheds angular momentum via its magnetic field interacting with its planetary accretion disk. This has the best chance, but still seems unlikely to me. My gut feeling is that even for a young star, the magnetic field won't be strong enough. Also, you need a large quantity of ionized gas close to the star for the magnetic field to interact with.
Can anyone help supply a plausible mechanism?
(I have an astronomy degree, but I've been out of the field for over a decade.)
From the summary "The antennae are tuned towards midrange infrared light (5-10 um), which is abundant on our cozy-warm Earth â" even at night."
But you can't extract work from a system which is in thermal equilibrium. This can't work unless the 'solar panels' are colder than the ambient night time radiation, which seems unlikely.
I couldn't read TFA (slashdotted?), I skim read the fine paper, but didn't find any reference to this idea. So has someone incorrectly introduced this idea somewhere between the paper and the slashdot summary, or am I missing something?
There are millions of things around us that have not been proven to be safe. Can you prove that eating off china plates is safe? If we use 'has not been proved safe' as our criterion, we will be paralysed, unable to do anything.
It only makes sense to take a precautionary avoidance strategy if there is some evidence that harm could occur. Basically, you either need a plausible mechanism, or a plausible correlation between the potentially-harmful-thing and some form of harm. Leaded petrol and tobacco both have plausible mechanisms for harm which could be appreciated by scientific knowledge of their times. Burning leaded petrol puts lead into the air, and lead is a known cumulative toxin. Autopsies on smokers shows they have blackened lungs. Any new medicine affects how our body operates in some way, and so could be harmful. It would have been quite rational to suspect these products of causing harm.
Asbestos may be a valid comparison - it has been used since antiquity, when they had neither the science nor statistics to suspect its effects. According to Wikipedia, a correlation with harm was noted in 1898, so any time last century, a case could have been made for not exposing children to it.
So call it $1500 revenue per driver - but that is revenue. If 40% of the fines go to some company, that means $2400 fines per driver. Clearly this can't be - think how paranoid you'd be about obeying every road law if you got fined $2400 last year - so it must come overwelmingly from out-of-towners.
I agree with the main point - this town is issuing way more traffic fines than can be justified by safety.
A good system of units needs: 1) Base units which are well defined and independently reconstructible (i.e. a suitably equipped lab can calibrate their equipment purely from the definition of the units.) 2) Logically constructed compound units (e.g. units of force are derived from the units of mass, time and distance.) 3) Logically constructed convenience units (e.g. kilometres for use for distances which would be an inconveniently large number of metres.) 4) To be widely used.
The initial choice of your base units is largely arbitrary - whether it was a from a not-very-accurate measure of a king's foot size or from a not-very-accurate measure of the Earth's circumference. Item (1) can be satisfied equally well (or, in the case of mass, badly) by the metric or imperial systems. The definition of the metre has long since changed from the size of the Earth to quantities measurable in a lab (as has the definition of the foot.)
The SI system (based on metric measures) beats the imperial system hands down on items 2 and 3, and because of this now has a large advantage also on item 4.
Item 2: In Imperial you might measure (heat) energy in BTU and mechanical energy in some mixture of foot-pounds-seconds, but then you need a conversion factor to compare the two. Such conversion factors are never needed in SI.
Item 3: Imperial also messes up the convenience units by having lots of weird conversion factors (e.g. an acre is (I think) a furlong by a chain. How many square feet is that? How many ounces in a ton?*) Metric uses convenience units constructed from base units via consistently named factors of 10 or 1000.
One could go a step further, and define your fundamental units in terms of fundamental physical constants (i.e. the Plank mass, Plank time and Plank distance, charge on an electron, etc.) In such a system of units, the speed of light is 1, the formula for the energy of a photon doesn't need a constant in it etc. In practice, we can't use such a system, because we can't measure (in particular) the universal gravitational constant G with sufficient accuracy. Every time we got a better measure of G, our entire system of units would need to be updated. (I.e. with current technology, this system can't satisfy requirement (1) above.)
* And how many different sorts of ounces and tons are there? It is quite a few.
Yes, we're better at estimating 1/3 than 3/5 (your example) - but that is because the denominator '3' is smaller than '5'. For your claim that people think in base 12, you'd need to show we're better at estimating 7/12 than we are 3/10.
No, 'lean' just refers to the mix of fuel and air. You put less fuel into the cylinder each cycle, and the energy of the fuel is used more efficiently. So you might end up with a 2000cc engine which performs like a 1500cc engine but consumes fuel like a 1300cc engine - except that you have the option to run richer (more fuel per cycle) if you need to, getting 2000cc performance at 2000cc fuel consumption (and also without the reduction in nitrogen oxide emission.)
I am not an automotive engineer, feel free to correct me if I've made errors in the above.
Something being part of your religion does not necessarily make it not illegal. In the USA, the standard used would be the Lemon test. If file sharing was criminal-illegal (rather than civil law illegal) and the 'church' challenged this on first amendment grounds, the state would need to show: 1 the law had a secular legislative purpose 2 the law's primary effect is not to advance or inhibit religion 3 the must not result in an "excessive government entanglement" with religion An anti file sharing law would have no trouble passing these tests.
Of course, this is all in Sweden, so different laws/precedent will apply.
While not as powerful as my suggestion, I think that every time I've wanted this feature, the C++ const pointer would have sufficed. To do it properly, not only does the object pointed to have to be unmodifiable, so too do any objects contained within that one, which C(++) does not do. (I.e. any pointer obtained via a 'const' pointer is also 'const'.)
However, it is a hand-crafted solution for one single data structure. I want something I can paint onto any data structure with a single keyword, and let the compiler deal with it behind the scenes.
My problem isn't that I don't know the boundaries of my algorithm, it is that I can't enforce those boundaries cheaply. Another way of looking at it is I'm writing a library function, and I don't trust the library's user to know the boundaries of my algorithm.
My number 1 missing feature in Java is the ability to set object references to be 'copy on write'.
I'm doing numerical/scientific programming. Say I have an object which contains an array, and a 'get' function to return that array. Currently I have two choices: I can return a pointer to my object's array, or make a copy of the array and return that.
Returning a pointer is very fast, but now my class is at the mercy of callers which might write into my array. Returning a copy is safe, but so long as the callers behave themselves and don't try to write to it, is a waste of time and memory. If I could return a "copy-on-write-reference" to my array, I'd get the best of both worlds.
Any reference reached via a copy-on-write-reference would also need to be copy-on-write. If you make copy-on-write a qualifier on a variable, this could be all enforced by the compiler.
Are there any languages which do something like this?
Someone/some people believe SCO is worth $2.1M? Wow. It might have been, when they declared bankruptcy, but they've spent rather more than that on the bankruptcy since then*, and if I recall correctly are trying to sell off everything they have left which might be of value for $0.6M, but are in legal difficulties because Novell says the sale (of licenses from Novell) can't go through without their approval.
* No, this doesn't make any sense to me either.
(Note: everything I know about SCO I got by reading Groklaw.)
Are the Chinese very generous in allowing access to their dinosaur quarry? Is there a shortage of Chinese paleontologists? (If so, why?) Was it really lead by a Chinese scientist but the western press gives us a biased story? Are there lots of these discoveries but the western press doesn't report them if made by a Chinese scientist? Was it just coincidence that one of only a few Europeans happened to get lucky? Do they have some exchange program, and we're just as likely to have a European dinosaur discovered by a Chinese scientist?
(Wild guess: China is somewhat short on paleontologists because China's per-capita wealth is fairly recent and paleontologists are a long lead-time item. Dr Hone's presence was in part to train the new wave of Chinese scientists. Also, he got lucky.)
Aside: TFA says "The research paper was published in Cretaceous Research in the online journal Science Direct." No - Science Direct is an aggregator/distributor of scientific papers in electronic form, from many journals. Cretaceous Research would be the journal.
Yes, they scoop up many organisms, then extract DNA and sequence bits of it. Except for sequences which match the DNA of something already known, they can't tell what the organisms were, or which fragments belong together.
If you proved they'd come from Polynesia, that really would be a big breakthrough - pushing back Polynesian settlement by more than 10,000 years. Easter Island and Hawai'i were settled within the last 2000 years.
Slashdot Mirror
First, note that all we have so far is an allegation. Although we tend to like SpaceX around here, Valador are currently only accused scum, not confirmed scum.
Second, the alleged defamation occurred on June 8 2011. courthousenews.com reports on the suit on June 16. So that is offence to suit in about a week!
Moreover, neutrino astronomy is pretty much the only thing that can give us warning (albeit only a few hours) if a nasty supernova happens in our vicinity
There are no candidate supernovae progenitors close enough to us to be dangerous. (I can't remember what the lethal radius is, but it is not terribly large.)
I once tried to find the nearest possible supernova progenitor, and the best I could find was gamma velorum A, at 260 parsecs away, but I didn't spend a long time on this. (I might have been only looking for type II progenitors.)
More info here, which mentions a danger radius of about 25 light years for a type II supernova.
In the last few years I have been at three universities, two in Australia, I have used Unix, and had support. However, I've never tried to use wireless, and in all cases I was using deparmental IT people rather than university central IT people.
So the single category which best sums up this story and so is used for the icon is... ... that the kid is British?
And the very next /. story has 'cellphone' as its category/icon.
While we're at it - why do red antique phone booths represent the UK?
OK, I've done some cursory research (abstracts and intros of a few papers.) I didn't find a review, however it seems that there has been quite a bit written about such angular momentum transfers, and the age-rotational period-mass relationship for stars. (So this result is a step in an already developed field, not a breakthrough.)
There was mention of interactions with a magnetized solar wind (i.e. a combination of my points 3 and 4 above) and also something called the Tayler-Spruit dynamo, which I think is about angular momentum transport between the star's core and envelope. For a young star, you'd expect the core to rotate faster than the envelope (conservation of angular momentum during the contraction) but the sun rotates like a solid body - same rotation period for all depths (or as far as we can probe by helioseismology.) The Tayler-Spruit appears to be a possible explanation for how a middle aged star like the sun can rotate like a solid body.
I'm happy enough with the idea that a star's mass determines its initial angular momentum (or, more likely, vice versa.) While not obviously true, it is certainly plausible. But once its angular momentum is set, how can it slow down? Here are all the possibilities I can think of:
* It expands (radius increases) and so it can spin slower for the same angular momentum. However, this would be very uninteresting - if we have luminosity and temperature, we already know the radius. Adding an extra measurement which correlates with radius would give us no new information. Also, main sequence stars change their radius very slowly. (But I'm not so sure about very young MS stars.)
* It redistributes its angular momentum from its envelope (which we observe) to its core. But this is the reverse of what I'd expect - the core would spin faster than the envelope, so any coupling between them would (rotationally) accelerate the envelope at the expense of the core.
* It sheds angular momentum via its stellar wind. But main sequence stars shed very little mass in their winds. (From memory, for the sun it is on the order of 10^-14 solar masses per year.) Even if some strange effect caused the wind to be expelled in the best direction for shedding angular momentum, I don't think this could give any appreciable slowdown. (Again, I'm not sure about very young stars.)
* It sheds angular momentum via its magnetic field interacting with its planetary accretion disk. This has the best chance, but still seems unlikely to me. My gut feeling is that even for a young star, the magnetic field won't be strong enough. Also, you need a large quantity of ionized gas close to the star for the magnetic field to interact with.
Can anyone help supply a plausible mechanism?
(I have an astronomy degree, but I've been out of the field for over a decade.)
I thought 'They're putting their FTP site computers down an abandoned mine full of particle detectors? That's sort of cool, but why?'
I suppose it says something about me that I find 'muon' a more recognizable word than "suite".
From the summary "The antennae are tuned towards midrange infrared light (5-10 um), which is abundant on our cozy-warm Earth â" even at night."
But you can't extract work from a system which is in thermal equilibrium. This can't work unless the 'solar panels' are colder than the ambient night time radiation, which seems unlikely.
I couldn't read TFA (slashdotted?), I skim read the fine paper, but didn't find any reference to this idea. So has someone incorrectly introduced this idea somewhere between the paper and the slashdot summary, or am I missing something?
There are millions of things around us that have not been proven to be safe. Can you prove that eating off china plates is safe? If we use 'has not been proved safe' as our criterion, we will be paralysed, unable to do anything.
It only makes sense to take a precautionary avoidance strategy if there is some evidence that harm could occur. Basically, you either need a plausible mechanism, or a plausible correlation between the potentially-harmful-thing and some form of harm. Leaded petrol and tobacco both have plausible mechanisms for harm which could be appreciated by scientific knowledge of their times. Burning leaded petrol puts lead into the air, and lead is a known cumulative toxin. Autopsies on smokers shows they have blackened lungs. Any new medicine affects how our body operates in some way, and so could be harmful. It would have been quite rational to suspect these products of causing harm.
Asbestos may be a valid comparison - it has been used since antiquity, when they had neither the science nor statistics to suspect its effects. According to Wikipedia, a correlation with harm was noted in 1898, so any time last century, a case could have been made for not exposing children to it.
but who knows...I could have ended up being a financial analyst
If you'd studied astronomy or physics, you likely would have.
So call it $1500 revenue per driver - but that is revenue. If 40% of the fines go to some company, that means $2400 fines per driver. Clearly this can't be - think how paranoid you'd be about obeying every road law if you got fined $2400 last year - so it must come overwelmingly from out-of-towners.
I agree with the main point - this town is issuing way more traffic fines than can be justified by safety.
This post is an example of autoplagurism.
A good system of units needs:
1) Base units which are well defined and independently reconstructible (i.e. a suitably equipped lab can calibrate their equipment purely from the definition of the units.)
2) Logically constructed compound units (e.g. units of force are derived from the units of mass, time and distance.)
3) Logically constructed convenience units (e.g. kilometres for use for distances which would be an inconveniently large number of metres.)
4) To be widely used.
The initial choice of your base units is largely arbitrary - whether it was a from a not-very-accurate measure of a king's foot size or from a not-very-accurate measure of the Earth's circumference. Item (1) can be satisfied equally well (or, in the case of mass, badly) by the metric or imperial systems. The definition of the metre has long since changed from the size of the Earth to quantities measurable in a lab (as has the definition of the foot.)
The SI system (based on metric measures) beats the imperial system hands down on items 2 and 3, and because of this now has a large advantage also on item 4.
Item 2: In Imperial you might measure (heat) energy in BTU and mechanical energy in some mixture of foot-pounds-seconds, but then you need a conversion factor to compare the two. Such conversion factors are never needed in SI.
Item 3: Imperial also messes up the convenience units by having lots of weird conversion factors (e.g. an acre is (I think) a furlong by a chain. How many square feet is that? How many ounces in a ton?*) Metric uses convenience units constructed from base units via consistently named factors of 10 or 1000.
One could go a step further, and define your fundamental units in terms of fundamental physical constants (i.e. the Plank mass, Plank time and Plank distance, charge on an electron, etc.) In such a system of units, the speed of light is 1, the formula for the energy of a photon doesn't need a constant in it etc. In practice, we can't use such a system, because we can't measure (in particular) the universal gravitational constant G with sufficient accuracy. Every time we got a better measure of G, our entire system of units would need to be updated. (I.e. with current technology, this system can't satisfy requirement (1) above.)
* And how many different sorts of ounces and tons are there? It is quite a few.
Yes, we're better at estimating 1/3 than 3/5 (your example) - but that is because the denominator '3' is smaller than '5'. For your claim that people think in base 12, you'd need to show we're better at estimating 7/12 than we are 3/10.
No, 'lean' just refers to the mix of fuel and air. You put less fuel into the cylinder each cycle, and the energy of the fuel is used more efficiently. So you might end up with a 2000cc engine which performs like a 1500cc engine but consumes fuel like a 1300cc engine - except that you have the option to run richer (more fuel per cycle) if you need to, getting 2000cc performance at 2000cc fuel consumption (and also without the reduction in nitrogen oxide emission.)
I am not an automotive engineer, feel free to correct me if I've made errors in the above.
Something being part of your religion does not necessarily make it not illegal. In the USA, the standard used would be the Lemon test. If file sharing was criminal-illegal (rather than civil law illegal) and the 'church' challenged this on first amendment grounds, the state would need to show:
1 the law had a secular legislative purpose
2 the law's primary effect is not to advance or inhibit religion
3 the must not result in an "excessive government entanglement" with religion
An anti file sharing law would have no trouble passing these tests.
Of course, this is all in Sweden, so different laws/precedent will apply.
While not as powerful as my suggestion, I think that every time I've wanted this feature, the C++ const pointer would have sufficed.
To do it properly, not only does the object pointed to have to be unmodifiable, so too do any objects contained within that one, which C(++) does not do. (I.e. any pointer obtained via a 'const' pointer is also 'const'.)
I've just found a couple of discussions on this -
http://www.velocityreviews.com/forums/t150742-how-do-java-programmers-cope-with-java-missing-c-const.html
http://www.javamex.com/java_equivalents/const_java.shtml
Nice - I didn't know this one, and may use it.
However, it is a hand-crafted solution for one single data structure. I want something I can paint onto any data structure with a single keyword, and let the compiler deal with it behind the scenes.
My problem isn't that I don't know the boundaries of my algorithm, it is that I can't enforce those boundaries cheaply. Another way of looking at it is I'm writing a library function, and I don't trust the library's user to know the boundaries of my algorithm.
My number 1 missing feature in Java is the ability to set object references to be 'copy on write'.
I'm doing numerical/scientific programming. Say I have an object which contains an array, and a 'get' function to return that array. Currently I have two choices: I can return a pointer to my object's array, or make a copy of the array and return that.
Returning a pointer is very fast, but now my class is at the mercy of callers which might write into my array. Returning a copy is safe, but so long as the callers behave themselves and don't try to write to it, is a waste of time and memory. If I could return a "copy-on-write-reference" to my array, I'd get the best of both worlds.
Any reference reached via a copy-on-write-reference would also need to be copy-on-write. If you make copy-on-write a qualifier on a variable, this could be all enforced by the compiler.
Are there any languages which do something like this?
I wish this was a moderation option.
Someone/some people believe SCO is worth $2.1M? Wow. It might have been, when they declared bankruptcy, but they've spent rather more than that on the bankruptcy since then*, and if I recall correctly are trying to sell off everything they have left which might be of value for $0.6M, but are in legal difficulties because Novell says the sale (of licenses from Novell) can't go through without their approval.
* No, this doesn't make any sense to me either.
(Note: everything I know about SCO I got by reading Groklaw.)
Are the Chinese very generous in allowing access to their dinosaur quarry? Is there a shortage of Chinese paleontologists? (If so, why?) Was it really lead by a Chinese scientist but the western press gives us a biased story? Are there lots of these discoveries but the western press doesn't report them if made by a Chinese scientist? Was it just coincidence that one of only a few Europeans happened to get lucky? Do they have some exchange program, and we're just as likely to have a European dinosaur discovered by a Chinese scientist?
(Wild guess: China is somewhat short on paleontologists because China's per-capita wealth is fairly recent and paleontologists are a long lead-time item. Dr Hone's presence was in part to train the new wave of Chinese scientists. Also, he got lucky.)
Aside: TFA says "The research paper was published in Cretaceous Research in the online journal Science Direct." No - Science Direct is an aggregator/distributor of scientific papers in electronic form, from many journals. Cretaceous Research would be the journal.
Yes, they scoop up many organisms, then extract DNA and sequence bits of it. Except for sequences which match the DNA of something already known, they can't tell what the organisms were, or which fragments belong together.
If you proved they'd come from Polynesia, that really would be a big breakthrough - pushing back Polynesian settlement by more than 10,000 years. Easter Island and Hawai'i were settled within the last 2000 years.
Megatokyo style