Well, yeah, but they didn't build the LHC accidentally.
They still need an accelerator bigger than the ones already running for the same reason they did before it broke. Just as someone who, presumably, wasn't driving (or owning) a car by accident when they got a flat tire. And the cheapest way to achieve those goals (better understanding of particle physics) is to fix the LHC.
And anyway, you don't need to drive, you can just walk, or take a bus, or ride a bicycle. Which is the analogous physical alternative to not using the LHC.
Theoretically, all but one bears may be smarter than the "average" bear. This requires that the last one be abysmally stupid, but *theoretically* it's still possible.
Yes. And I've never noticed before that having both lines is redundant, since the second export cancels the first. Duh... too much reliance on copy-paste.
# don't overwrite history from several sessions shopt -s histappend
and
# save history after each command instead of logout PROMPT_COMMAND='history -a;'${PROMPT_COMMAND}
in your ~/.bashrc
You might also want to add this, too:
# don't put duplicate lines in the history. See bash(1) for more options export HISTCONTROL=ignoredups #... and ignore same sucessive entries. export HISTCONTROL=ignoreboth
I didn't imply the uninstaller should remove everything a package creates. I just meant there's no obvious way of finding out some of those files that are left there. Which was the point of the discussion.
(Although I did also see things like/usr/share/games/some-game-I-don't-remember-the-name-of/saves - which were left but empty. And that after purging the packages.)
But it still took me a year of running Ubuntu to find that one out.
And it only mentions files that are "declared" by the package, I think. If the awesome-widget creates files afterward (or even if in its install scripts, sometimes) they might not be mentioned.
I've often found config and cache files left over after uninstalling various not-as-awesome-as-advertised widgets that are not mentioned by dpkg.
Do you have any links detailing this a bit? I've seen references to echoing things to "/sys/devices/*/*/power/state" (I have zero such files on my system), and various tricks for specific devices, but I can't seem to find anything comprehensive. For instance, I couldn't find out if unloading a driver will {always|sometimes|never} power off a component or just leave it drawing power unused.
I have a laptop I use only few features of, and a headless server whose everything-integrated chipset consumes 40W despite the fact that I only use the Ethernet and SATA controllers. I'm sure much of the rest (video, audio, PCI slot, all ports except Ethernet) could be simply turned off, but I only managed to find how for a few small things like WOL.
Not a critique as such and only vaguely on topic: Does anyone else find it interesting that parent found it natural to represent ternary using 1-2-3 and binary using 0-1?
That was actually my first instinct too when I was "reading" the thing...
If pink unicorns are the one self aware force in the universe, then the pink unicorns are God. What about Russel's teapot?:)
The universe only exists in peoples minds. How do you know that? There's no evidence to the contrary, but no evidence of your statement, either---other than your perceptions, which as you already noticed are no more proof of the lack of a universe as they are proof of the existence of one, or that of invisible pink unicorns frolicking happily in invisible green meadows.
Scientists who study the universe are actually only studying their own perceptions and to interpret perceptions without any meaning behind it is to just function as a knowledge gatherer collecting meaningless data and organizing it using the scientific method. That's no more defensible than saying that philosophers studying their own perceptions are actually studying the universe that generated them.
Which means that if you don't accept the heuristic that "gee, I can seem to find rules governing my perceptions (e.g., apples seem to fall when unsupported), and I perceive things (e.g., people) that seem to discover rules as good as I do, even better sometimes--why, this means there's some sort of universe that follows rules and that I and others like me actually perceive", then you don't have any justification to believe "only my perceptions exist, and I am God".
(If you don't understand why, try to prove that the two statements mean _different_ things. In your proof, don't forget to state _when_ two statements about the world are different.)
Thanks. Actually, it has surprised me too. (The analysis' conclusion, not its quality. Although... Never mind.)
I'm a great fan of nukes in general, mainly because they seem the only workable solution for the (apparent) future energy crisis. There's one element important that's missing above (since I was mainly discussing nukes vs. solar-thermal):
AFAIK none of the other solutions can scale up to potentially covering the entire energy usage of the planet (or the US, for that matter), generally because of absolute resource cost (either materials & energy for building or simply space).
Which is what surprised me; if TFA's estimates are correct* then solar-thermal is also comparable and might actually win big versus nukes. (And consequently over everything else.)
(*: in truth, I didn't check them. There are a lot of subtle and gross errors that can be made, intentionally or not**, which can add an order of magnitude to the bottom line.)
(**: and TFA has some incentives to be overenthusiastic...)
It could also mean âoefor all eternity, starting now, until you die from the torture, and then again until the end of timeâ. It could also mean âoejust after you die and go to hell, which we might help 'cuz you deserve to get there quickerâ.
Which _some_ have actually said. Few said it openly, but still.
How about 10000 solar farms, each one mile per side?
If you think that's impractical, try to calculate how much area is needed to generate 3.3 TW of energy (US's share) with your technology of choice. The biggest nuclear plants I know of are around 1 GW, and I haven't seen one yet that uses up less than a square kilometer.
(If you're not a nuke fan like me, try the same calculation with the technology of your choice. Include strip mines and oil fields for fossil-fuel plants.)
We have* to cover up comparable areas of land no matter how we generate electricity. (Try looking up how much we use up right now; it's larger than you'd think; in fact, it's comparable to what TFA mentions.)
We can cover up forests or deserts just as well, which would you pick?
*: Yes, we have to. Every alternative is highly correlated with a decrease of around four billion in the world population. This means that four billion people must die, either before or shortly after, before we can reduce world energy usage by an order of magnitude.
1. Deserts. Also, try looking up how much space _any_ power plant needs, and then try to calculate how much area is taken by current power plants, given that we use up 15 TW (3.3 TW in the US alone).
2. The same way China's potential single largest-energy grid would look like from US's spy satellites. Large and uninteresting. BTW, the point of having mirrors as solar concentrators is to get the light to a tower, _not_ in space. There's a 50 MW solar-thermal plant on this map, see if you can find it: http://maps.google.com/maps?ll=37.2175,-3.061111&spn=0.3,0.3&t=k&q=37.2175,-3.061111
Others gave good responses for the individual issues, I'm not going to waste bits on that.
The most important element about power generation is not what are the costs of a particular method, but how do those costs relate to every other method.
The point is that we use a lot of energy, and we know we're going to be using a lot more. Either that, or population _will_ scale back to pre-industrialization levels. If we stop producing as much energy as we use, between four and five billion people must disappear (either before or quickly after). This is not and argument that it won't or even that it shouldn't happen, but it's good to keep in mind that it's the _only_ alternative.
So, back to costs. Whatever technology we use to generate energy, it has some costs: land usage, certain damage (to us & the environment), risk of damage, use of resources (for building or for fuel), and human resources needed for construction and maintenance. (Time is already included since we're talking about power.)
It's useful to consider how much of these costs we'd need to pay if (a) we were using only a certain method for power generation and (b) to switch to that method of power generation.
Since the power usage is 15 TW and growing, the (a)-part of costs is huge for any method. (Try calculating how many cubic meters of aluminum are used in all the power cables in the world (or the US), or what area is used only for the transmission towers and poles.) So, if you don't consider a drastic population reduction acceptable, those costs must be born, we only need to pick which method is cheaper.
The (b)-part of the costs is just as interesting. Even more importantly, at least the part of the energy that is generated using fuel (85+% of those 15 TW) _will_ eventually need to be replaced. (Of course, _when_ is debatable.) So those costs will need to be paid anyway.
Building nuclear powerplants, closer or not to the consumers, is a good idea (and I'm a big fan), but it also has huge costs:
There are 439 power reactors in the world, producing 6.5% of its power. This means we have to build 6300 more power plants to satisfy current usage.
*** Let's take land usage: A random sample on Google Maps gives a 1 km^2 size for a nuclear plant (meaning area unusable for other purposes, but ignoring the uranium mines and processing plants and waste storage), meaning we'd need 6300 square kilometers for the plants. TFA mentions 8400 miles^2 for solar in the US, which is about 3.3 TW of the 15 in the US. So land costs for solar fall within an order of magnitude even in worst case conditions, and ignoring any future developments. As far as I know, every other technology is about the same, even the non-renewable ones.
Power transmission costs should be included here. It applies to everything except in-your-backyard/on-your-rooftop generation; this works for every tech, more or less, but in that case the land cost is much bigger (you need the same area, but in places where people want to live).
Also, we already have a functional electric grid, so even if we replaced _all_ power generation with _any_ technology, the costs due to the grid are very low. *** The cost of certain damage. Let's break it up: 1) Environment damage caused by mere land usage: it falls within an order of magnitude, as per the previous analysis. 2) Environment damage caused to produce the materials needed to build the plants. This should be grow roughly linear to the area covered, and decrease with the complexity of the thing built. Most of the area occupied by solar thermal is mirrors, for which the primary material is sand.
In all other casesâ"eolian, nuclear, geothermal, hydro and tidal, photovoltaic, even fossil fuelâ"it's higher technology construction. I'd guess that's a net win for solar-thermal.
The generator costs (just the turbines and the electric parts, i.e. without reactors) are about the same for everything except photovoltaics. 3) Damage due to running the things:
There's no "friction" because the usual definition of that word implies non-conservative interactions inside the materials of the interacting objects.
In the case of black holes, there can't be any such "internal interactions", because they have no (observable) internal structure. Their only features are mass, charge and other quantum numbers (all of them, but the electrical charge and spin are probably the only ones that are important at those levels) and the event horizon. The event horizon depends only on those features; note that it's not an "object", it does not interact in any way with anything that crosses it, it's just a surface drawn through empty (but curved) space. So "swallowing" something happens pretty much like free-fall.
There are some features that would look similar to friction, though:
1) When the black hole swallows something (eg, a nucleon), this is equivalent to a perfectly plastic impact between the black hole (moving) and a nucleon (approximately static) resulting in another larger but slower black hole because of the conservation of momentum & energy. (Note that in the first such impact the nucleon is _much_ larger than the black hole, so it would look as if it stopped for an instant. The effect of each nucleon would be progressively smaller after that.)
2) Since the black hole is so small, it's _much_ likelier to absorb an individual particle rather than a whole atom. If it happens to swallow a neutron, this doesn't change things muchâ"except that the "source" nucleon might become unstable and undergo fission; the conservation laws might also cause some local effect when the nuclear bonds are broken.
However, if the black hole swallows up an electron or a proton (or even a single quark), things can get much interesting: it becomes charged, and the electrical interactions become _much_ more important than gravity. If it swallowed an electron, it might even form an "atom" together with some nearby nucleus. It may "touch" nothing else for a very long time then for the same reason electrons don't hit each other... If it hits a proton, it can behave very much like a (very small) hydrogen ion, pair up with an electron, and likewise become insulated from normal matter.
Note that the above assumes a neutral black hole. If the black hole is not neutral from the start, it will _not_ crash through the Earth in free-fall, it will mostly behave as described above.
(The above description might happen relative to color charges, when swallowing a quark, but that's way above my head to reason about. I'd guess in that case it might very quickly swallow the rest of the nucleon, so only electric charge remains.)
However, if a black hole _does_ get fast enough that it can't get caught in an atom like that, the result will be a very quickly moving electric charge through the Earth. It will interact electrically with matter, which will propagate energy throughout the Earth through the later's chemical's bonds, and that _is_ non-conservative, so it would look a bit like friction. A very slight bit.
Slashdot Mirror
I'm kind of curious about something, though too lazy to test it myself by opening out my machines.
Did you (anytime recently) try the exact same thing (3â"4 dozen tabs open) on the same machine with, say, Netscape Navigator or Firefox 1.0?
Are there significant differences?
You mean it has will be already working.
You didn't get even as far as the future semi-conditionally modified subinverted plagal past subjunctive intentional, did you?
Well, yeah, but they didn't build the LHC accidentally.
They still need an accelerator bigger than the ones already running for the same reason they did before it broke. Just as someone who, presumably, wasn't driving (or owning) a car by accident when they got a flat tire. And the cheapest way to achieve those goals (better understanding of particle physics) is to fix the LHC.
And anyway, you don't need to drive, you can just walk, or take a bus, or ride a bicycle. Which is the analogous physical alternative to not using the LHC.
It'd be more relevant if the bear gets a shotgun, too. And how about friken lasers?
Theoretically, all but one bears may be smarter than the "average" bear. This requires that the last one be abysmally stupid, but *theoretically* it's still possible.
Yes. And I've never noticed before that having both lines is redundant, since the second export cancels the first. Duh... too much reliance on copy-paste.
Thank you!
I was wondering how it did that.
On Ubuntu it certainly does. Search for 'scp' in /etc/bash_completion for how it does. (It actually runs 'ls' over ssh to find completion strings.)
If you're using bash, try adding
# don't overwrite history from several sessions
shopt -s histappend
and
# save history after each command instead of logout
PROMPT_COMMAND='history -a;'${PROMPT_COMMAND}
in your ~/.bashrc
You might also want to add this, too:
# don't put duplicate lines in the history. See bash(1) for more options ... and ignore same sucessive entries.
export HISTCONTROL=ignoredups
#
export HISTCONTROL=ignoreboth
I didn't imply the uninstaller should remove everything a package creates. I just meant there's no obvious way of finding out some of those files that are left there. Which was the point of the discussion.
(Although I did also see things like /usr/share/games/some-game-I-don't-remember-the-name-of/saves - which were left but empty. And that after purging the packages.)
+1 informative, true.
But it still took me a year of running Ubuntu to find that one out.
And it only mentions files that are "declared" by the package, I think. If the awesome-widget creates files afterward (or even if in its install scripts, sometimes) they might not be mentioned.
I've often found config and cache files left over after uninstalling various not-as-awesome-as-advertised widgets that are not mentioned by dpkg.
Do you have any links detailing this a bit? I've seen references to echoing things to "/sys/devices/*/*/power/state" (I have zero such files on my system), and various tricks for specific devices, but I can't seem to find anything comprehensive. For instance, I couldn't find out if unloading a driver will {always|sometimes|never} power off a component or just leave it drawing power unused.
I have a laptop I use only few features of, and a headless server whose everything-integrated chipset consumes 40W despite the fact that I only use the Ethernet and SATA controllers. I'm sure much of the rest (video, audio, PCI slot, all ports except Ethernet) could be simply turned off, but I only managed to find how for a few small things like WOL.
Thanks!
How exactly do you shut down the USB ports? I don't remember ever seeing that among laptop-mode's settings.
Well, it did happen in just a few minutes. That's like a 10^15 factor in power, for objects that are within couple of orders of magnitudes in size.
(The big factor is for 2 billion years over five minutes; what you're talking about would swallow some more orders of magnitude, but still...)
Not a critique as such and only vaguely on topic: Does anyone else find it interesting that parent found it natural to represent ternary using 1-2-3 and binary using 0-1?
That was actually my first instinct too when I was "reading" the thing...
Which means that if you don't accept the heuristic that "gee, I can seem to find rules governing my perceptions (e.g., apples seem to fall when unsupported), and I perceive things (e.g., people) that seem to discover rules as good as I do, even better sometimes--why, this means there's some sort of universe that follows rules and that I and others like me actually perceive", then you don't have any justification to believe "only my perceptions exist, and I am God".
(If you don't understand why, try to prove that the two statements mean _different_ things. In your proof, don't forget to state _when_ two statements about the world are different.)
Thanks. Actually, it has surprised me too. (The analysis' conclusion, not its quality. Although... Never mind.)
I'm a great fan of nukes in general, mainly because they seem the only workable solution for the (apparent) future energy crisis. There's one element important that's missing above (since I was mainly discussing nukes vs. solar-thermal):
AFAIK none of the other solutions can scale up to potentially covering the entire energy usage of the planet (or the US, for that matter), generally because of absolute resource cost (either materials & energy for building or simply space).
Which is what surprised me; if TFA's estimates are correct* then solar-thermal is also comparable and might actually win big versus nukes. (And consequently over everything else.)
(*: in truth, I didn't check them. There are a lot of subtle and gross errors that can be made, intentionally or not**, which can add an order of magnitude to the bottom line.)
(**: and TFA has some incentives to be overenthusiastic...)
It could also mean âoefor all eternity, starting now, until you die from the torture, and then again until the end of timeâ. It could also mean âoejust after you die and go to hell, which we might help 'cuz you deserve to get there quickerâ.
Which _some_ have actually said. Few said it openly, but still.
How about 10000 solar farms, each one mile per side?
If you think that's impractical, try to calculate how much area is needed to generate 3.3 TW of energy (US's share) with your technology of choice. The biggest nuclear plants I know of are around 1 GW, and I haven't seen one yet that uses up less than a square kilometer.
(If you're not a nuke fan like me, try the same calculation with the technology of your choice. Include strip mines and oil fields for fossil-fuel plants.)
They didn't forget.
We have* to cover up comparable areas of land no matter how we generate electricity. (Try looking up how much we use up right now; it's larger than you'd think; in fact, it's comparable to what TFA mentions.)
We can cover up forests or deserts just as well, which would you pick?
*: Yes, we have to. Every alternative is highly correlated with a decrease of around four billion in the world population. This means that four billion people must die, either before or shortly after, before we can reduce world energy usage by an order of magnitude.
Yeah. Now try calculating how much space every other power plant we have uses up. You'll be surprised.
1. Deserts. Also, try looking up how much space _any_ power plant needs, and then try to calculate how much area is taken by current power plants, given that we use up 15 TW (3.3 TW in the US alone).
2. The same way China's potential single largest-energy grid would look like from US's spy satellites. Large and uninteresting. BTW, the point of having mirrors as solar concentrators is to get the light to a tower, _not_ in space. There's a 50 MW solar-thermal plant on this map, see if you can find it: http://maps.google.com/maps?ll=37.2175,-3.061111&spn=0.3,0.3&t=k&q=37.2175,-3.061111
3. See answer 1.
Others gave good responses for the individual issues, I'm not going to waste bits on that.
The most important element about power generation is not what are the costs of a particular method, but how do those costs relate to every other method.
The point is that we use a lot of energy, and we know we're going to be using a lot more. Either that, or population _will_ scale back to pre-industrialization levels. If we stop producing as much energy as we use, between four and five billion people must disappear (either before or quickly after). This is not and argument that it won't or even that it shouldn't happen, but it's good to keep in mind that it's the _only_ alternative.
So, back to costs. Whatever technology we use to generate energy, it has some costs: land usage, certain damage (to us & the environment), risk of damage, use of resources (for building or for fuel), and human resources needed for construction and maintenance. (Time is already included since we're talking about power.)
It's useful to consider how much of these costs we'd need to pay if (a) we were using only a certain method for power generation and (b) to switch to that method of power generation.
Since the power usage is 15 TW and growing, the (a)-part of costs is huge for any method. (Try calculating how many cubic meters of aluminum are used in all the power cables in the world (or the US), or what area is used only for the transmission towers and poles.) So, if you don't consider a drastic population reduction acceptable, those costs must be born, we only need to pick which method is cheaper.
The (b)-part of the costs is just as interesting. Even more importantly, at least the part of the energy that is generated using fuel (85+% of those 15 TW) _will_ eventually need to be replaced. (Of course, _when_ is debatable.) So those costs will need to be paid anyway.
Building nuclear powerplants, closer or not to the consumers, is a good idea (and I'm a big fan), but it also has huge costs:
There are 439 power reactors in the world, producing 6.5% of its power. This means we have to build 6300 more power plants to satisfy current usage.
***
Let's take land usage: A random sample on Google Maps gives a 1 km^2 size for a nuclear plant (meaning area unusable for other purposes, but ignoring the uranium mines and processing plants and waste storage), meaning we'd need 6300 square kilometers for the plants. TFA mentions 8400 miles^2 for solar in the US, which is about 3.3 TW of the 15 in the US. So land costs for solar fall within an order of magnitude even in worst case conditions, and ignoring any future developments. As far as I know, every other technology is about the same, even the non-renewable ones.
Power transmission costs should be included here. It applies to everything except in-your-backyard/on-your-rooftop generation; this works for every tech, more or less, but in that case the land cost is much bigger (you need the same area, but in places where people want to live).
Also, we already have a functional electric grid, so even if we replaced _all_ power generation with _any_ technology, the costs due to the grid are very low.
***
The cost of certain damage. Let's break it up:
1) Environment damage caused by mere land usage: it falls within an order of magnitude, as per the previous analysis.
2) Environment damage caused to produce the materials needed to build the plants. This should be grow roughly linear to the area covered, and decrease with the complexity of the thing built. Most of the area occupied by solar thermal is mirrors, for which the primary material is sand.
In all other casesâ"eolian, nuclear, geothermal, hydro and tidal, photovoltaic, even fossil fuelâ"it's higher technology construction. I'd guess that's a net win for solar-thermal.
The generator costs (just the turbines and the electric parts, i.e. without reactors) are about the same for everything except photovoltaics.
3) Damage due to running the things:
There's no "friction" because the usual definition of that word implies non-conservative interactions inside the materials of the interacting objects.
In the case of black holes, there can't be any such "internal interactions", because they have no (observable) internal structure. Their only features are mass, charge and other quantum numbers (all of them, but the electrical charge and spin are probably the only ones that are important at those levels) and the event horizon. The event horizon depends only on those features; note that it's not an "object", it does not interact in any way with anything that crosses it, it's just a surface drawn through empty (but curved) space. So "swallowing" something happens pretty much like free-fall.
There are some features that would look similar to friction, though:
1) When the black hole swallows something (eg, a nucleon), this is equivalent to a perfectly plastic impact between the black hole (moving) and a nucleon (approximately static) resulting in another larger but slower black hole because of the conservation of momentum & energy. (Note that in the first such impact the nucleon is _much_ larger than the black hole, so it would look as if it stopped for an instant. The effect of each nucleon would be progressively smaller after that.)
2) Since the black hole is so small, it's _much_ likelier to absorb an individual particle rather than a whole atom. If it happens to swallow a neutron, this doesn't change things muchâ"except that the "source" nucleon might become unstable and undergo fission; the conservation laws might also cause some local effect when the nuclear bonds are broken.
However, if the black hole swallows up an electron or a proton (or even a single quark), things can get much interesting: it becomes charged, and the electrical interactions become _much_ more important than gravity. If it swallowed an electron, it might even form an "atom" together with some nearby nucleus. It may "touch" nothing else for a very long time then for the same reason electrons don't hit each other... If it hits a proton, it can behave very much like a (very small) hydrogen ion, pair up with an electron, and likewise become insulated from normal matter.
Note that the above assumes a neutral black hole. If the black hole is not neutral from the start, it will _not_ crash through the Earth in free-fall, it will mostly behave as described above.
(The above description might happen relative to color charges, when swallowing a quark, but that's way above my head to reason about. I'd guess in that case it might very quickly swallow the rest of the nucleon, so only electric charge remains.)
However, if a black hole _does_ get fast enough that it can't get caught in an atom like that, the result will be a very quickly moving electric charge through the Earth. It will interact electrically with matter, which will propagate energy throughout the Earth through the later's chemical's bonds, and that _is_ non-conservative, so it would look a bit like friction. A very slight bit.