You are right- but it takes just a few J/cm^2 to make a mirror no longer a mirror. That's the cost of high reflectivity. A strong ablative armor is a superior route for laser protection. Unfortunately, that's also heavy and not well suited to guided ordnance.
I don't even see it being pitched as ABM. The congressional briefings on the system even mention that many-MW-scale lasers would be required to injure an incoming ballistic RV. This may however be highly useful for carrier protection- especially if not located on the carrier. Cruisers in the carrier group, spaced properly, could very likely take out ASM projectiles, especially since they tend to be cruise-missiles, not rotating warheads, and being able to target the incoming weapon from the side as opposed to head-on would limit the atmospheres disruption of the beam.
Most potential enemies that have ballistic ASMs are using shitty enough ballistics that we can intercept them with standard issue ABM systems (Aegis cruisers).
You're right- though at typical projectile velocities, the atmosphere makes a piss-poor coolant. Why pulse the laser in nanoseconds if you have a laser with sufficient cooling and available power as to hold the beam on the target? Obviously, we'll need MW lasers if we ever want to take truly well shielded and rotating/tumbling projectiles out, but for most things flying through the air, being able to hold 50kW on it for a reasonable amount of time is brutally devastating. Even coated in mirror.
Lockheed has demonstrated in-flight subsonic rocket destruction with 10kW lasers.
Oh, quite simple. Because 2.5kW in a that small of an area is more than enough to make that mirror no longer a mirror. You can try this at home, if you have sufficiently tough conductors. 10kJ is obscenely high for an estimate of what it takes to oblate a mirror surface. Usually a few J/cm^2 is enough to do the trick, and degradation (micropitting) starts happening at the 1J/cm^2 levels. ITER has some publicly available studies on this exact topic. Assuming a focal area of 126 cm^2 (roughly 5 inch diameter) and 2.5kW total absorbed energy, we're talking ~20J/cm^2- enough to turn the mirror into slag in fractions of a second. Now, in the case of a fast-rotating mirror object, this may be a lot more difficult to capitalize on, so ballistic RVs may be out of the question, but something like an anti-ship missile, or a cruise missile would be easy pickins'
They were willing to murder millions of people to achieve utopia and they still didn't get it.
LOL. Are you serious right now? And that is why you fail.
So, some people that were smarter and more committed than us ended up being genocidal maniacs, and thus the economic theory they started out championing is bunk. Does anyone really need to blow holes in that logic?
Here in the Pacific Northwest of the USA, I can say we had a snowless winter down in the lowlands, which is pretty unusual.
What's really unusual though, is there's no snow on the mountains bordering the lowlands. It didn't even snow much up there. The mountains in January looked like they normally do by about August. It was a pretty weird year. There's talk of drought worries now, since our water supply is snowfall runoff in the foothills.
All sample sizes are statistically significant, you just need to understand the error bars.
In this case, assuming a true accident rate of 4.5% (human-driven rate, bad assumption- but it's all we've got), a reasonable distribution, and a population size of 48, you have a 20% possibility of getting 4 accidents in the sample (8.3%), which is far too high to call conclusive by any stretch. A better conclusion would be: Very weak correlation found between self-driving cars and increase in accident incidence. Need more data to see if correlation is real.
Sigh. If you took a sample of 48 US human-driven cars, you'd have a 20% chance of getting 4 accidents out of that 48.
I'm not trying to say that's huge, but that sample size of 48 is far too small to draw conclusions from statistics that contain millions of samples. The error bars are massive.
Sure it is, but with a sample size of 48, most assumptions of distribution are going to give you some very big error bars.
If there were 2 of them, and 1 got in an accident in 6 months, would you really think it said anything about the car?
No, we do know that, from the Cosmic Microwave Background. The early universe has been directly observed to be extremely homogeneous.
No, we really don't know that. The CMB is exactly the proof you're looking for. If all of its photons were emitted when space itself was very, very small, and space is now very, very big, it would indeed appear very homogeneous, and very very redshifted. The only real argument against it happening at a single point is that QED says that just doesn't work for them- but then again, they've always hated singularities, and I somewhat agree with them. But they're not arguing that it didn't happen at nearly a single point.
Actually, they're just used by academics, everywhere, period. Regardless of their beliefs. Science, a while ago, decided not to define itself in religious terms. I wouldn't take it so personally, because it's not. It's not militant atheism.
Everything is just speculation from unimaginative scientists who think they know what happened 14 billion years ago at some random spot that they can't even point their finger in the general direction of.
Why would any scientist do that? They would merely point right here, just like any scientist anywhere else would. There is no center of the big bang, we are the center along with every other point.
Note: We can't get an accurate police report 20 minutes after the event with 20 eye witnesses, but many are dead set that we KNOW what happened during the big bang. When you think about things like this, use your head and think about the police report.
No, I don't think we have any clue what really happened during it, or even for a significant amount of time after it. But we have pretty solid evidence that it happened. The metric expansion of space is happening, and the CMB is there just like it should have been. It comes from all directions in space, just like it should have. It's the afterglow of the big bang. Bask in its beauty.
Your skepticism seems borne of ignorance, and that's sad. Read up on it so you can at least be legitimately skeptical.
Every bit of CO2 emitted from cars into the atmosphere is a pollutant because it would not be there otherwise.
The extremity of that view is why it is wrong.
Cars can absolutely be run on chemical carbon fuel sources that are derived from the extant carbon cycle. Think biofuel.
Inserting another link in the carbon cycle to extract energy from it for the purpose of doing work is not a bad thing. The problem is that we're sourcing the carbon for the work from outside of the cycle. (Below the soil layer)
It's very true. If you pipe O2 from outside of the room's oxygen cycle into that room, you are in fact polluting it.
Fortunately, We're not creating a hell of a lot of O2 out of non-O2 cycle O. Are you actually in the fossil CO2 emissions are a pollutant camp? I had thought I had your name associated with the other side of that argument.
Pollutants disturb processes, CO2 is *part* of a very important process, it's just out of balance right now.
LOL. I get what you're trying to say, really I do...
But too much water in your gasoline very much disturbs the process of combustion. Your logic is circular, through and through.
CO2 is part of the carbon cycle, an integral part of it. However, it's very capable of disturbing the process in certain cases of rate change faster than the other major part of the cycle (biomass) being able to handle it.
Notice that it shows carbon flow in both directions - so for example every year vegetation sucks 121.3Gt of carbon out of the atmosphere while releasing 60 Gt back directly, and a further 60GT back from the soil (decomposition, presumably) - for a net flow of 1.3Gt out of the atmosphere.
I don't see how that can possibly be accurate unless the Earth's vegetation mass is increasing. I'd be very surprised to learn that is the case, though I could be wrong.
it's that the ecological carbon cycle is not well equipped to deal with changes in the the total amount of carbon present
I disagree entirely. Our current arable land distribution may not be well equipped, but equilibrium has and will be attained again for every level of carbon in the cycle. Whether we, or most of the extant species today survive to see the new equilibrium is an entirely different discussion.
A million years from today, the fossil record we leave right now will appear as an extinction event, no doubt about it, but the biosphere's overall ecological system isn't going to be hurt by us. If we want to cause a new extinction event to clear some room for evolution, so be it. The last major one was a landmark event for evolution. Maybe the next will be even more incredible;)
I don't know, you seem to be making the argument that nuclear contamination is not a pollutant. After all, it's part of the environment.
While fossil-sourced CO2 emissions may be "part of the environment" by some ridiculous interpretation of "environment", the fact is, that carbon comes from outside of the carbon cycle. It is a pollutant.
I've been trying to push this exact point to deniers for a long time. It's a damn simple concept. Inserting ourselves into the carbon cycle and getting work from it isn't the problem, it's the injection of carbon into the cycle from outside of it without an equal amount of sequestration that's causing the problem.
Either offset the injected carbon with biomass (or sequester in some other way) or quit fucking pulling it out of the dirt and throwing it into the cycle and denying that we're the cause of the statistical change.
for the systems that in fact do, BSD kernels tend to be quite a bit smaller than their Linux equivalent with similar functionality, so the decision has a direct impact on cost.
Additionally, using Linux the license requires to (gasp) release the sources, and before this getting better in the last decade, for most companies that was a total no-go.
I don't disagree with you- yet still, they use Linux. I suspect it's simply because the ecosystem is richer, but I don't know for sure.
BTW, an example of where embedded systems/appliances of significant size were/are often BSD based would be networking equipment; maybe this is because the BSDs seem to be widely known and have a reputation among networking people.
Again, that's false as a generalization.
Juniper is of course the well known BSD control-plane networking hardware giant, however, Cisco has used Linux since its Nexus line. SOHO routers largely migrated from VxWorks to Linux, and now almost solely run Linux. Ever tear apart the firmware on your "Smart TV?" Both of mine run Linux.
The baseboard controller on my motherboard- runs Linux.
Anyway, as pointed out above, most embedded systems are so small that there's no way to run either a BSD or Linux, or any OS for that matter, on, rendering the whole discussion rather pointless. In fact I'd suppose you'd need at least 8M of RAM (maybe 16M for Linux) to get going; I've developed my share of embedded systems and even the thought of having 8 or 16 KB of RAM makes me go "hmm, big thing".
Sure, but the ones who can, run Linux. It's not an absolute rule, but you could make a safe bet on it.
Also, it's exceedingly rare to run 32-bit micros with that little ram these days. PoP is such a big thing that it's economical to throw 64-128M on top of the micro for pennies, and our discussion obviously doesn't apply to sub-32bit micros.
Hell, I worked on a project back in the earlier 2000's that used an ARM7- running Linux. Can you run your BSD without an MMU? You can Linux.
I'm not arguing the merits of your argument, only the integrity of the presented facts. I have no problem with BSD, and never, as an embedded developer working professionally or as an amateur, has the open source license governing use of the code influenced my decision on which kernel to use. Your argument works in theory, it just doesn't match reality. Time to revisit it and figure out why the GPL isn't as much of a turn-off as you hypothesize.
His statement seemed quite generalized with OpenSSH/SSL cited as an example.
I personally don't partake in the license wars, but I don't think the success of any particular piece of software was tied to the license choice.
OpenSSH is an excellent piece of software with lots of excellent people working on it, as is Linux. As to why Linux succeeded more than BSD? I couldn't say. I've worked in both of the kernels, and they're equally heinous (as kernels are usually wont to be)
They've got their own lists of idiosyncrasies, and both do most things pretty damn well, and a few things each pretty damn excellently. I think it mostly comes down to the position of Linux grabbing the niche of Unix on commodity hardware before BSD had a solid offering, thus getting most of the developer mindshare. That kind of momentum is hard to compete against- because it's not easy working in multiple kernels. You get in a mindset that set of working knowledge that is highly tailored to the one you're working on.
Switching back and forth has always been a pain to me from the coding aspect, and I've never paid a second of time thinking about the license. I'm fine with both license models, really.
Disclaimer: I professionally work in the Linux kernel, as well as amateur kernel-level and below firmware hacking for embedded devices running many kernels. I've also done amateur work in BSD kernels.
Slashdot Mirror
You are right- but it takes just a few J/cm^2 to make a mirror no longer a mirror. That's the cost of high reflectivity. A strong ablative armor is a superior route for laser protection. Unfortunately, that's also heavy and not well suited to guided ordnance.
7) Figure out how to design a guided missile that rotates at a high rate
I don't even see it being pitched as ABM. The congressional briefings on the system even mention that many-MW-scale lasers would be required to injure an incoming ballistic RV. This may however be highly useful for carrier protection- especially if not located on the carrier. Cruisers in the carrier group, spaced properly, could very likely take out ASM projectiles, especially since they tend to be cruise-missiles, not rotating warheads, and being able to target the incoming weapon from the side as opposed to head-on would limit the atmospheres disruption of the beam.
Most potential enemies that have ballistic ASMs are using shitty enough ballistics that we can intercept them with standard issue ABM systems (Aegis cruisers).
You're right- though at typical projectile velocities, the atmosphere makes a piss-poor coolant. Why pulse the laser in nanoseconds if you have a laser with sufficient cooling and available power as to hold the beam on the target? Obviously, we'll need MW lasers if we ever want to take truly well shielded and rotating/tumbling projectiles out, but for most things flying through the air, being able to hold 50kW on it for a reasonable amount of time is brutally devastating. Even coated in mirror.
Lockheed has demonstrated in-flight subsonic rocket destruction with 10kW lasers.
Oh, quite simple. Because 2.5kW in a that small of an area is more than enough to make that mirror no longer a mirror. You can try this at home, if you have sufficiently tough conductors. 10kJ is obscenely high for an estimate of what it takes to oblate a mirror surface. Usually a few J/cm^2 is enough to do the trick, and degradation (micropitting) starts happening at the 1J/cm^2 levels. ITER has some publicly available studies on this exact topic. Assuming a focal area of 126 cm^2 (roughly 5 inch diameter) and 2.5kW total absorbed energy, we're talking ~20J/cm^2- enough to turn the mirror into slag in fractions of a second. Now, in the case of a fast-rotating mirror object, this may be a lot more difficult to capitalize on, so ballistic RVs may be out of the question, but something like an anti-ship missile, or a cruise missile would be easy pickins'
Eating is not using.
From someone named MrL0G1C of all things. Thank you for the laugh
They were willing to murder millions of people to achieve utopia and they still didn't get it.
LOL. Are you serious right now?
And that is why you fail.
So, some people that were smarter and more committed than us ended up being genocidal maniacs, and thus the economic theory they started out championing is bunk. Does anyone really need to blow holes in that logic?
Here in the Pacific Northwest of the USA, I can say we had a snowless winter down in the lowlands, which is pretty unusual.
What's really unusual though, is there's no snow on the mountains bordering the lowlands. It didn't even snow much up there. The mountains in January looked like they normally do by about August. It was a pretty weird year. There's talk of drought worries now, since our water supply is snowfall runoff in the foothills.
Agree 100%
All sample sizes are statistically significant, you just need to understand the error bars.
In this case, assuming a true accident rate of 4.5% (human-driven rate, bad assumption- but it's all we've got), a reasonable distribution, and a population size of 48, you have a 20% possibility of getting 4 accidents in the sample (8.3%), which is far too high to call conclusive by any stretch. A better conclusion would be: Very weak correlation found between self-driving cars and increase in accident incidence. Need more data to see if correlation is real.
Sigh. If you took a sample of 48 US human-driven cars, you'd have a 20% chance of getting 4 accidents out of that 48.
I'm not trying to say that's huge, but that sample size of 48 is far too small to draw conclusions from statistics that contain millions of samples. The error bars are massive.
Sure it is, but with a sample size of 48, most assumptions of distribution are going to give you some very big error bars.
If there were 2 of them, and 1 got in an accident in 6 months, would you really think it said anything about the car?
No, we do know that, from the Cosmic Microwave Background. The early universe has been directly observed to be extremely homogeneous.
No, we really don't know that. The CMB is exactly the proof you're looking for. If all of its photons were emitted when space itself was very, very small, and space is now very, very big, it would indeed appear very homogeneous, and very very redshifted. The only real argument against it happening at a single point is that QED says that just doesn't work for them- but then again, they've always hated singularities, and I somewhat agree with them. But they're not arguing that it didn't happen at nearly a single point.
Actually, they're just used by academics, everywhere, period. Regardless of their beliefs. Science, a while ago, decided not to define itself in religious terms. I wouldn't take it so personally, because it's not. It's not militant atheism.
Everything is just speculation from unimaginative scientists who think they know what happened 14 billion years ago at some random spot that they can't even point their finger in the general direction of.
Why would any scientist do that? They would merely point right here, just like any scientist anywhere else would. There is no center of the big bang, we are the center along with every other point.
Note: We can't get an accurate police report 20 minutes after the event with 20 eye witnesses, but many are dead set that we KNOW what happened during the big bang. When you think about things like this, use your head and think about the police report.
No, I don't think we have any clue what really happened during it, or even for a significant amount of time after it. But we have pretty solid evidence that it happened. The metric expansion of space is happening, and the CMB is there just like it should have been. It comes from all directions in space, just like it should have. It's the afterglow of the big bang. Bask in its beauty.
Your skepticism seems borne of ignorance, and that's sad. Read up on it so you can at least be legitimately skeptical.
Every bit of CO2 emitted from cars into the atmosphere is a pollutant because it would not be there otherwise.
The extremity of that view is why it is wrong.
Cars can absolutely be run on chemical carbon fuel sources that are derived from the extant carbon cycle. Think biofuel.
Inserting another link in the carbon cycle to extract energy from it for the purpose of doing work is not a bad thing. The problem is that we're sourcing the carbon for the work from outside of the cycle. (Below the soil layer)
It's very true. If you pipe O2 from outside of the room's oxygen cycle into that room, you are in fact polluting it.
Fortunately, We're not creating a hell of a lot of O2 out of non-O2 cycle O. Are you actually in the fossil CO2 emissions are a pollutant camp? I had thought I had your name associated with the other side of that argument.
Pollutants disturb processes, CO2 is *part* of a very important process, it's just out of balance right now.
LOL. I get what you're trying to say, really I do...
But too much water in your gasoline very much disturbs the process of combustion. Your logic is circular, through and through.
CO2 is part of the carbon cycle, an integral part of it. However, it's very capable of disturbing the process in certain cases of rate change faster than the other major part of the cycle (biomass) being able to handle it.
Notice that it shows carbon flow in both directions - so for example every year vegetation sucks 121.3Gt of carbon out of the atmosphere while releasing 60 Gt back directly, and a further 60GT back from the soil (decomposition, presumably) - for a net flow of 1.3Gt out of the atmosphere.
I don't see how that can possibly be accurate unless the Earth's vegetation mass is increasing. I'd be very surprised to learn that is the case, though I could be wrong.
it's that the ecological carbon cycle is not well equipped to deal with changes in the the total amount of carbon present
I disagree entirely. Our current arable land distribution may not be well equipped, but equilibrium has and will be attained again for every level of carbon in the cycle. Whether we, or most of the extant species today survive to see the new equilibrium is an entirely different discussion. ;)
A million years from today, the fossil record we leave right now will appear as an extinction event, no doubt about it, but the biosphere's overall ecological system isn't going to be hurt by us. If we want to cause a new extinction event to clear some room for evolution, so be it. The last major one was a landmark event for evolution. Maybe the next will be even more incredible
I don't know, you seem to be making the argument that nuclear contamination is not a pollutant. After all, it's part of the environment.
While fossil-sourced CO2 emissions may be "part of the environment" by some ridiculous interpretation of "environment", the fact is, that carbon comes from outside of the carbon cycle. It is a pollutant.
I've been trying to push this exact point to deniers for a long time. It's a damn simple concept. Inserting ourselves into the carbon cycle and getting work from it isn't the problem, it's the injection of carbon into the cycle from outside of it without an equal amount of sequestration that's causing the problem.
Either offset the injected carbon with biomass (or sequester in some other way) or quit fucking pulling it out of the dirt and throwing it into the cycle and denying that we're the cause of the statistical change.
for the systems that in fact do, BSD kernels tend to be quite a bit smaller than their Linux equivalent with similar functionality, so the decision has a direct impact on cost. Additionally, using Linux the license requires to (gasp) release the sources, and before this getting better in the last decade, for most companies that was a total no-go.
I don't disagree with you- yet still, they use Linux. I suspect it's simply because the ecosystem is richer, but I don't know for sure.
BTW, an example of where embedded systems/appliances of significant size were/are often BSD based would be networking equipment; maybe this is because the BSDs seem to be widely known and have a reputation among networking people.
Again, that's false as a generalization.
Juniper is of course the well known BSD control-plane networking hardware giant, however, Cisco has used Linux since its Nexus line. SOHO routers largely migrated from VxWorks to Linux, and now almost solely run Linux. Ever tear apart the firmware on your "Smart TV?" Both of mine run Linux. The baseboard controller on my motherboard- runs Linux.
Anyway, as pointed out above, most embedded systems are so small that there's no way to run either a BSD or Linux, or any OS for that matter, on, rendering the whole discussion rather pointless. In fact I'd suppose you'd need at least 8M of RAM (maybe 16M for Linux) to get going; I've developed my share of embedded systems and even the thought of having 8 or 16 KB of RAM makes me go "hmm, big thing".
Sure, but the ones who can, run Linux. It's not an absolute rule, but you could make a safe bet on it.
Also, it's exceedingly rare to run 32-bit micros with that little ram these days. PoP is such a big thing that it's economical to throw 64-128M on top of the micro for pennies, and our discussion obviously doesn't apply to sub-32bit micros.
Hell, I worked on a project back in the earlier 2000's that used an ARM7- running Linux. Can you run your BSD without an MMU? You can Linux.
I'm not arguing the merits of your argument, only the integrity of the presented facts. I have no problem with BSD, and never, as an embedded developer working professionally or as an amateur, has the open source license governing use of the code influenced my decision on which kernel to use. Your argument works in theory, it just doesn't match reality. Time to revisit it and figure out why the GPL isn't as much of a turn-off as you hypothesize.
His statement seemed quite generalized with OpenSSH/SSL cited as an example.
I personally don't partake in the license wars, but I don't think the success of any particular piece of software was tied to the license choice.
OpenSSH is an excellent piece of software with lots of excellent people working on it, as is Linux. As to why Linux succeeded more than BSD? I couldn't say. I've worked in both of the kernels, and they're equally heinous (as kernels are usually wont to be)
They've got their own lists of idiosyncrasies, and both do most things pretty damn well, and a few things each pretty damn excellently. I think it mostly comes down to the position of Linux grabbing the niche of Unix on commodity hardware before BSD had a solid offering, thus getting most of the developer mindshare. That kind of momentum is hard to compete against- because it's not easy working in multiple kernels. You get in a mindset that set of working knowledge that is highly tailored to the one you're working on.
Switching back and forth has always been a pain to me from the coding aspect, and I've never paid a second of time thinking about the license. I'm fine with both license models, really.
Disclaimer: I professionally work in the Linux kernel, as well as amateur kernel-level and below firmware hacking for embedded devices running many kernels. I've also done amateur work in BSD kernels.
Ya, it's pretty cool to see it boot on some VM hypervisors. I'm told there's real hardware somewhere that it works on, too.