Our best solution... Is to take a lot of fissionable material, a big, deep hole... perhaps a single nuke... or many nukes, and hopefully start a large enough fissionable reaction that the planet's core can be reheated.
The amount of material required would be on the order of 10 trillion metric tonnes. That'd be a bit heavy to lift over there.
It would be cheaper to just build solenoid windings around the planet to induce our own field, if we decide a magnetic field is useful.
Re:Crack Pots Win Again
on
Tornado in a Can
·
· Score: 4, Insightful
This again proves that it's not a degree or an education, but thinking outside the box that will move technology forward.
...overlooking all of the contributions that were made to technology by people _with_ degrees.
Education does not make you smart, but neither does lack of education. And in general, problem-solving's easier when you have more than intuition in your toolkit.
Re:beta-stability versus particle-emission stabili
on
Tetraneutron Discovered
·
· Score: 3, Interesting
So far, this reasoning applies to 4He just as much as it applies to a tetraneutron. So why would 4He be so much more stable? Well, the Pauli exclusion principle says that in a tetraneutron, the first two neutrons can both go in the lowest energy level, with their spins in opposite direction, but the third and fourth have to go in a higher energy level.
By this reasoning, we'd expect 2n to be much more stable than 4n. Has this construct been produced and studied?
Lastly, what could we expect for 3n, 5n, and 6n? Would the odd number of nucleons make 3n less stable (vs. the strong force) than 4n due to some shell-filling rule? Ditto 5n vs. 6n? Would 6n be more or less stable (vs. the strong force) than 4n? (more particles to mutually attract, but more of them in the higher energy shell).
My apologies for being a pest, but I've been interested in the subject for quite a while, but lack the background to derive the numbers for myself (went into engineering, not physics).
Yeah I know what you think. You think school is and should be designed to prepare people for work. I think school should be designed to teach people how to think.
A school _should_ do both.
The vast majority of people _in_ school are in it for the former. Face it, most people don't _want_ to think more than necessary. Even then, a school that just wants to prepare people for industry _must_ teach people to think, because it's a vital skill no matter where you're working. So, your complaint is pretty silly.
Both the article and the posting blurb specifically mention "preparing for industry", which is why it was the focus of my post.
many universities not only fail to prepare students for the game industry, but still don't take it seriously.
Taking preparation for a video game design career seriously is like taking preparation for a rock musician career seriously. At best you can argue that it's an art that people can pursue out of interest. Claiming that universities in any way do their students a disservice by not offering it as a career-preparation stream is very silly.
In both industries, you have a very small number of people who can possibly make a living at it, because you just don't need that many providers in the mainstream market. This is even more true with video games than with music, as niche markets are few and local markets are nonexistant. Anyone who *isn't* one of the big players in either industry had better be doing it because they like it, and have a day job that they're trained for, because they'll have a hard time making a living.
Video game creation also doesn't require as much specialized training as music. It requires a _lot_ of training, but most of it is the same stuff you'd get doing a CS major or 3D or 2D art major or a drama/literature major (depending on the aspect of game design you're targetting). The usefulness of a specialized stream of study is questionable.
In short, I think the importance of "preparing people for the video game industry" is overstated.
Infact thrashing occurs when an OS is unable to keep a large enough RMS(Resident Memory Size) of a process. It has *nothing* to do with the cache.
In Computer Engineering, "thrashing" refers to the overflow of any kind of cache, be it a CPU's cache of system RAM or system RAM's cache of the OS's virtual memory space (RAM plus swap plus what-have-you).
You are thinking about large integers. Actually at the circuit level, multiplication is not done in O(log(N)) steps, but instead, they just have blazingly fast adders.
I have been treating adders as operating in constant time, as we're working with small integers.
The grid approach to multiplication that everyone sees in undergrad microprocessor design requires N serial additions. A tree structure still requires N additions, but done in parallel in log(N) levels (as you pointed out). This is where my statement came from.
Very large integers would indeed require O(log(N)^2) cycles, due to non-negligeable adder delay, but we can make the constant-time approximation for our purposes (especially since the pipeline is likely tuned to have adds take one cycle).
For #1, realize that this is going to greatly increase the data size of many applications. The larger the data size, the higher the chance of cache misses. In general, this is a loss, not a win.
wouldn't the chance of cache misses depend on the caching policy? How does the data size matter?
Data size matters because a program will typically access a fixed number of working variables, not a fixed amount of data. If a program's working set size stays at, say, 1000 words, and you move from a 32-bit to a 64-bit architecture, you need a cache with twice as much storage space to hold the working set without thrashing.
There's easily enough die area to double the sizes of the L1 and L2 caches; the problem is that it slows down cache access (more latency cycles fetching something from L1 is a Bad Thing).
Certain types of load work with constant size instead of constant word count, but most of those deal with working sets large enough that you'll thrash no matter what.
The gain with 64-bit processors is one of address space and nothing more.
Which includes better behaviour for those programs that have to fake larger address space. That would be a speed increase.
Nothing running on x86 will do that. Unless you're running old DOS programs in real mode, you're already working with a flat address space. Typically 2 gigs of this is available to user programs (with the rest being mapped to kernel or device space). If you have a problem with a working set larger than 2 gigabytes, you already have a Sun/$other_vendor machine to solve it on.
Larger address space targets the _future_ problem of desktop users who want many gigabytes of memory.
A fringe benefit is being able to more efficiently map multi-gigabyte files into memory space, but performance for this kind of task is limited by disk latency and controller bandwidth, not memory architecture.
For #2, realize that some integer operations are O(N) where N is the number of bits involved. 64-bit multiplication and division are slower than the same 32-bit operations. Period.
If area is not an issue, you can do a multiplication in log N steps. Current latencies suggest that this has been done for a while, so I wouldn't expect to see much of a difference at all for multiplying numbers. It's division that takes O(N) steps (you can apply brute force to reduce the proportionality constant, but the order remains).
Re:Just to remind people why more bits is good..
on
AMD's 64-bit Plot
·
· Score: 5, Informative
2^64 addressing is not the only benefit of the change. FPUs see additional benefit when they have more bits. More bits means more precission; this is very important and desirable, especially when working with numbers that have fractional components. For proper 3D rendering, physics models, and anything else that involves computing numbers that have fractional parts, more is better. When the FPU can handle a double in one clock cycle because it works natively on 64-bit IEEE floating point numbers, you will notice a performance boost in addition to the increased accuracy.
Um, all current x86s already handle 64-bit IEEE double-precision floats natively (actually more like 80 bits, for "extended double-precision"). The FP register file has been this wide for quite a while.
There will be no performance or precision boost for floating-point math from moving the rest of the chip to 64-bit registers/datapaths.
Mill the text into aluminum sheets, hard-anodize the sheets, store in argon.
Guaranteeing storage in argon for 1000 years will get a bit tricky.
My favourite method: Paint in oxide suspensions on cloth woven from alumina (corundum), and then fire the pages and sew/bind them with alumina thread. The resulting book is resistant to physical wear and fire (the center of a bonfire would probably blur the letters, but that's about it), and is virtually invulnerable to chemical attack.
Look. The basic problem with space travel is real simple. Chemical propellants don't have enough energy per unit weight to do the job. As a result, all space vehicles are mostly fuel tank. They all have dinky payloads for their size.
The cost of even an unmanned launch is not dominated by the fuel cost. If needing a 20:1 ratio between fuel and cargo was the only hindrance, we'd be in the sub-$100/lb regime even with exotic fuels.
So, the theoretical minimum cost of chemical launch would seem to be quite low.
Incidentally, the "cheap, dumb booster" is a myth. Most of the cost comes from making boosters light. It's easy to make a cheap, heavy booster, but it will barely get off the ground.
So basically, we need cheap, light composites. We'll get there eventually (we have the "light" part, just not the "cheap").
While I'm not going to suggest that I, alone, constitute a control group, I can personally attest that since giving up TV in 1996 and radio in 1997 -- and I lived in Boston so no car, thus no billboards -- I now go into stores like Target (generally when someone I'm with goes) and it's, "nope, don't need that, nope, don't need that... All I see when I go, though, is people walking around, aimlessly, picking things up and sticking it in their cart. I used to be more or less just like them. The difference is beyond palpable.
My impulse spending has dropped too, and TV had little to do with it. It's called "growing up and learning to manage your money", and most of us do go through it as we age.
Car rims and the Abdominizer nicely illustrate that not _all_ people develop this level of self-control. However, even people without the self-discipline to not buy shiny things are limited by the fact that things like rent come _first_. Their disposable income is only what's left over after housing and food are taken care of, and that's not a lot (regardless of income level, usually; people tend to respond to a prolonged surplus by moving into a nicer place).
And as for the control group, I'm curious; which category does 21B (that's nine zeros) in credit card debt [news.com.au] fit into? The "neccessary" or the "increase in quality of life?"
It represents people paying for the privilege of buying things a month earlier than they otherwise would be able to. Whether that's a calculated expenditure or bad planning depends on the person.
Again, you fail to demonstrate that most income is spent on frivolities. And without that point, your argument just doesn't hold. Calling me names won't go further towards supporting your argument.
Here is a very logical and well written essay on UFO skepticism. [dabsol.co.uk] In particular, I would like to direct your attention to the section entitled, "Occam's Razor and the Skeptics", roughly two thirds of the way down. [...] What a debunker will do is mutilate and butcher the observations until it can be "explained" by one of the simpler hypotheses, which is the inverse of the proper approach. The proper approach is to alter the hypothesis to accommodate the observations. One should never alter the observations to conform with a hypothesis
This is true when observations are taken under carefully controlled conditions (that is, after all, part of the scientific method). However, chance eyewitness accounts of *anything* under non-ideal conditions are about as closely related to reality as a typical "inspired by true events" TV-movie. This is the bane of police officers taking witness statements from accident scenes; it also makes it reasonable to claim that any given interpretation in the memo was not a correct one, especially given that known phenomena almost certainly accounted for at least some of the items described.
This feeds back into the "extraordinary claims require extraordinary evidence" rule of thumb. If observations appear to contradict all expectations, and the observations are open to question, then it is fair to assert that the observations are likely to be at least partly mistaken. Note that this does not assert ironclad proof; only likelihood.
If you want guesses as to the other points you raise, sure, I'll give them; but without having been there that night, they're so much hot air.
Blind conjectures as follows:
The lighthouse hypothesis could explain a light appearing to move in the forest, but it doesn't explain how they observed what they described "as being metallic in appearance and triangular in shape, approximately two to three meters across the base and approximately two meters high." It doesn't explain how it could have "bank(s) of blue lights underneath".
Silouette of trees obstructing the light would do this quite nicely. Most of the light showing at the top, some glow at the bottom, and enough of a glow at the sides to give the impression of shininess. I can believe that the blue colour was an illusion; colour sense is royally screwed up in low-light conditions (light dim enough to be perceived as monochrome often looks pale blue or green). Without actually taking a look at this lighthouse, I have no explanation offered for why the pulsing light was described as red.
It doesn't attempt to explain why "the animals on a nearby farm went into a frenzy."
A meteor as bright as the full moon had passed overhead a few minutes ago. This is described in the link I cited. Or it could just as easily have been some other trigger; animal noise needn't be constant.
It doesn't explain how the object vanished and was spotted again "an hour later near the back gate."
Obstructed by trees as the observers moved would be my first guess. Other explanations doubtless exist.
it can't explain the relationship... ie WHY they recorded a "peak reading in the three depressions and near the center of the triangle formed by the depressions. A nearby tree had moderate (.05-.07) readings on the side of the tree toward the depressions."
That one's easy. Trees aren't radioactive. Any excess background was probably from rocks (my father had a few thorite samples at one point; drove a radiation counter nuts). Point the counter at a tree, and the tree blocks half of the background. Move so that you no longer have line of site to wherever the rocks in question are, or even move farther from the deposit, and you get a reduced count. Dirt will also do a decent job of blocking beta rays, as long as it's not itself radioactive.
It doesn't explain how "At one point it appeared to throw off glowing particles and then broke into five separate white objects and then disappeared." It doesn't explain how "three star-like objects were noticed in the sky. Two objects to the north and one to the south [which] moved rapidly in sharp angular movements and displayed red, green and blue lights.", or "The objects to the north appeared to be elliptical through an 8-12 power lens. They then turned to full circles.", or "The object to the south was visible for two or three hours and beamed down a stream of light from time to time." (Yes I know it mentions these last observations. Saying the above is "probably" just stars is NOT an adequate scientific explanation for these very specific and detailed observations corroborated by multiple eye witnesses)
You left out the part about the "red sun-like light" that pulsed and gave off the glowing particles observation being through trees, which means it could have been just about anything. Best guess: one or more people with flashlights checking out the site. A red pulsing light sounds more like a campfire, but wouldn't move.
I have no explanation for the distant lights observed on the horizon, but am confident that one of the many usual glowing-moving-light explanations applies.
So, in conclusion, the lighthouse hypothesis attempts to 'mutilate and butcher the observations until it can be "explained" by one of the simpler hypotheses'.
Per my comments above, I think that taking all of the observations at face value would be even less accurate, especially given the evidence offered that _some_ of them (the disturbance caused by the meteor and the lighthouse's pulsing light) are very likely to not be the result of spacecraft activity (as they were classified in the report). The scientific method includes acknowledging noisy data as such.
UFOSkeptic [ufoskeptic.org] a must read for all "science types", written by Dr. Bernard Haisch.
I'm afraid I'm not terribly impressed with this site. After reading through these documents, it became clear that Dr. Haisch has a habit of jumping to the most favourable possible conclusion given incomplete evidence (as opposed to saying "the evidence is incomplete; here are the options and we don't know which is true").
The most thought-provoking case of this was his discussion of Fermi's Paradox. The paradox is that observations to date suggest that there are a very large number of worlds in the galaxy hospitable to intelligent water-based life, and yet we see no evidence of it and none of it has provably come to visit. Dr. Haisch notes that this either means that colonizing civilizations don't last long, or that aliens _do_ come to visit, and immediately concludes the latter. If anything, the lack of strong evidence of visitation or beacons or the like suggests that the former case is the more probable.
As a side note, the implications of this chain of reasoning are fascinating to consider. Either civilizations almost inevitably eradicate themselves, or they almost inevitably become permanently introverted, or they almost inevitably move somewhere else (either a virtual world, a la "Calculating God", or another universe (a la the Sublimed Elders from the "Culture" novels). Another option is that even under favourable conditions, sapient life, or perhaps complex life of any form, is extremely rare. Yet another option is that there is some other factor affecting habitability of worlds that we haven't found yet that eliminates most from consideration.
Whatever the case, there is by no means convincing evidence for the conclusion that aliens must be visiting us. Yet, the whole site is filled with jumps of logic like that.
What about redesigning the shuttle to launch from a maglev accelerated platform, which might be able to lift it to LEO, then fire internal engines or external rockets to leave the atmosphere. Electricity sure is cheap these days.
Firstly, LEO is already outside the atmosphere, so your second phase makes little sense. You'd actually just be doing a course correction (any initial ballistic launch trajectory would be an orbit that intersects Earth's surface).
Secondly, you'd have serious problems keeping the gun from destroying itself on firing. If you have air in the barrel, the coils, rails, or what-have-you have to deal with a mach-25 sonic boom at ground zero. If you don't have air in the barrel, you have to figure out how to keep an aperture the size of the space shuttle open while allowing no air to pass through it (actually, forcing air to flow *out* of it, if possible). This is possibly do-able with extremely strong jets of air beside the aperture.
Thirdly, your gun will be tens of kilometres long if it fires cargo, and thousands of kilometres long if it fires manned craft. Acceleration must be low enough not to damage the cargo, and you have a lot of delta-V to build up. A cargo gun would have to be vertical or near-vertical; the turning radius at reasonable lateral acceleration is larger than the gun. So, you have to build a 10-km tower. The manned gun would have to be a nearly-flat ramp ending above most of the atmosphere, because a human-safe lateral acceleration requires a turning radius that is again longer tham most of the gun. In summary, even a cargo-rated magnetic cannon is likely to be impractical to build.
The "super gun" is a special case, as it can sustain a substantially stronger acceleration than a magnetic cannon. However, it too is huge, and a space-capable version has not been demonstrated to my knowledge (just sub-orbital capable). You also run into serious materials problems scaling it up to accept projectiles the size of even an unmanned shuttle (you're stuck with very small cargo capsules).
Lastly, while electricity is cheap, building a very large launch facility isn't. Your construction cost gets amortized into the launch cost, over the maintenance lifetime of the facility (plan on an amortization time of at most 10-20 years). This problem is an important one for laser launching facilities and space elevators, too (my own calculations show that you'd need _extremely_ high ascent speeds on an elevator to move enough cargo to keep the launch cost below even current costs).
Food for thought. I'm honestly not sure if we'll see a practical replacement for chemical rockets this century (elevator is the best candidate, and it'll be quite some time before materials production matures and other problems are solved).
Furthermore, I think it's a bit dismissive in this case to call it "just some object in the air", like it could be a weather balloon or swamp gas or something. This is an object that moves and behaves like no known terrestrial phenomenon.
Someone had the common sense to go to the event site and look in the direction indicated by the report. Must have been a really cool-looking incongruity if you didn't recognize the illusion.
Advertising works because it makes a hole that you now need to fill with the product in question. It tells you that you stink, you're stupid, you're abs aren't trim enough, that you aren't dating someone cute enough, that you'd be OH SO MUCH HAPPIER if you could just get that new Lexus, [...] For you to argue that runaway consumerism doesn't exist is to argue that advertising does not work
By and large, it doesn't. When was the last time you paid attention to commercials, online or in conventional media? Do *you* have a burning need to buy that Lexus or palm-pilot or to drink Pepsi because the artist-du-jour told you to?
Advertising influences _what_ people buy quite strongly (by building brand awareness), but not so much how much they spend on buying things. It represents corporations slugging it out with each other to make sure that the money that will be spent, will be spent on them.
A high-tier executive may spend most of their money on frivolous items. The rest of us spend most of it on things that are necessities (rent/mortgage, food) or things that do substantially increase our quality of life (getting a car instead of using public transit, eating a fancy meal, going to a movie).
Your argument that we'd be much happier making half as much money and kicking our "addiction" assumes that most of our money is spent on things that do not contribute to our happiness. This does not appear to be the case for most people.
It correctly pointed out that Russia wasn't the only entity hindering the space station's development.
Multiple architectures turns out to be very hard.
on
Transmeta Astro Processor
·
· Score: 4, Insightful
Support for new instruction set extensions like SSE or MMX could be added with a simple firmware upgrade. A new code-morphing frontend could turn the Crusoe from an x86-compatible chip to a PowerPC, MIPS, or SPARC-compatible chip in seconds
This turs out to be much more difficult than it first appears. There are a number of low-level architectural features - especially in the memory interface, but elsewhere too - that are very difficult to emulate if you've built a processor using different assumptions. This means that while you might be able to emulate a PPC/MIPS/SPARC on a Crusoe - or even on a PC - by dynamically recompiling code, the only architecture that would perform well would be one with a good match to your actual hardware. The original Crusoe chips were designed from the start to emulate Intel processors, and this new chip is presumably in the same boat.
maybe the human race itself will survive, but it will most likely not be sufficient to maintain itself, and will just die out anyway.
As long as the destination environment isn't hostile, you don't need very many humans to survive (the 50/500 rule for breeding populations).
If you require an industrial base - e.g. if you were colonizing a hostile environment and needed habitats - the size of a small city would still be fine. What is the smallest community that can be self-sufficient industrially?
In summary, I think that making colonies that are viable in the long term does not require an unmanageable starting size or resource base.
I think that the technology/knowledge to create birth control pills for men has been around for a while. I imagine they will be much safer, too, since sperm is manufactured on a frequent regular basis, the pill would just have to affect that process.
Wrong on pretty much all counts, actually.
Stopping ovulation in women is straightforward - you're trying to stop a once-a-month event, and the female body already has a shut-down mechanism built in (ovulation stops during pregnancy). The pill just triggers this mechanism (tricks the body into thinking it's pregnant).
Men are designed to produce sperm all the time. There is no built-in shut-down mechanism to trigger. You also have to stop production of *all* of the hundreds of millions of sperm cells produced between sexual encounters, as opposed to stopping just one egg from being released. A male contraceptive that eliminates 99.9% of sperm production is still useless.
And because you're trying to inhibit a function that's never normally shut down, you have to start from scratch when figuring out how to do it, and live with the fact that a male contraceptive that's 100% effective runs a real risk of causing permanent damage if not very carefully designed.
It could probably be taken as little as 24-36 hours before sex to have its effect, and it would most likely not affect hormone levels.
Hormone manipulation is just about the only way to affect sperm production. What do you think drives it? Hormones are the body's signalling system for stopping/starting body processes.
It's only now, after decades of research, that relatively safe, reasonably effective approaches to male contraception are being developed, and we have a long way to go before they're mature.
Seriously. If privatization of space continues to grow, and launches become more afforadable, I'm predicting we may see businesses offering to launch your media into space, where the only thing that will destroy your data is the occassional asteroid collision.
The problem with, say, backing up to a satellite full of drives (or even just launching a box of tapes or CDs) is that most media will degrade quite quickly in space. You're bathed in enough ionizing radiation to make electronics go funny every few minutes to every few weeks, and that's when there *isn't* a solar flare going on. Magnetic and optical media are more resistant to radiation, but are far from immune. Think of this as being put under an airport x-ray machine for as long as it's up there.
Multiple earth-based sites gives much better reliability.
Slashdot Mirror
Our best solution... Is to take a lot of fissionable material, a big, deep hole... perhaps a single nuke... or many nukes, and hopefully start a large enough fissionable reaction that the planet's core can be reheated.
The amount of material required would be on the order of 10 trillion metric tonnes. That'd be a bit heavy to lift over there.
It would be cheaper to just build solenoid windings around the planet to induce our own field, if we decide a magnetic field is useful.
This again proves that it's not a degree or an education, but thinking outside the box that will move technology forward.
...overlooking all of the contributions that were made to technology by people _with_ degrees.
Education does not make you smart, but neither does lack of education. And in general, problem-solving's easier when you have more than intuition in your toolkit.
So far, this reasoning applies to 4He just as much as it applies to a tetraneutron. So why would 4He be so much more stable? Well, the Pauli exclusion principle says that in a tetraneutron, the first two neutrons can both go in the lowest energy level, with their spins in opposite direction, but the third and fourth have to go in a higher energy level.
By this reasoning, we'd expect 2n to be much more stable than 4n. Has this construct been produced and studied?
Lastly, what could we expect for 3n, 5n, and 6n? Would the odd number of nucleons make 3n less stable (vs. the strong force) than 4n due to some shell-filling rule? Ditto 5n vs. 6n? Would 6n be more or less stable (vs. the strong force) than 4n? (more particles to mutually attract, but more of them in the higher energy shell).
My apologies for being a pest, but I've been interested in the subject for quite a while, but lack the background to derive the numbers for myself (went into engineering, not physics).
Yeah I know what you think. You think school is and should be designed to prepare people for work. I think school should be designed to teach people how to think.
A school _should_ do both.
The vast majority of people _in_ school are in it for the former. Face it, most people don't _want_ to think more than necessary. Even then, a school that just wants to prepare people for industry _must_ teach people to think, because it's a vital skill no matter where you're working. So, your complaint is pretty silly.
Both the article and the posting blurb specifically mention "preparing for industry", which is why it was the focus of my post.
many universities not only fail to prepare students for the game industry, but still don't take it seriously.
Taking preparation for a video game design career seriously is like taking preparation for a rock musician career seriously. At best you can argue that it's an art that people can pursue out of interest. Claiming that universities in any way do their students a disservice by not offering it as a career-preparation stream is very silly.
In both industries, you have a very small number of people who can possibly make a living at it, because you just don't need that many providers in the mainstream market. This is even more true with video games than with music, as niche markets are few and local markets are nonexistant. Anyone who *isn't* one of the big players in either industry had better be doing it because they like it, and have a day job that they're trained for, because they'll have a hard time making a living.
Video game creation also doesn't require as much specialized training as music. It requires a _lot_ of training, but most of it is the same stuff you'd get doing a CS major or 3D or 2D art major or a drama/literature major (depending on the aspect of game design you're targetting). The usefulness of a specialized stream of study is questionable.
In short, I think the importance of "preparing people for the video game industry" is overstated.
Infact thrashing occurs when an OS is unable to keep a large enough RMS(Resident Memory Size) of a process. It has *nothing* to do with the cache.
In Computer Engineering, "thrashing" refers to the overflow of any kind of cache, be it a CPU's cache of system RAM or system RAM's cache of the OS's virtual memory space (RAM plus swap plus what-have-you).
You are thinking about large integers. Actually at the circuit level, multiplication is not done in O(log(N)) steps, but instead, they just have blazingly fast adders.
I have been treating adders as operating in constant time, as we're working with small integers.
The grid approach to multiplication that everyone sees in undergrad microprocessor design requires N serial additions. A tree structure still requires N additions, but done in parallel in log(N) levels (as you pointed out). This is where my statement came from.
Very large integers would indeed require O(log(N)^2) cycles, due to non-negligeable adder delay, but we can make the constant-time approximation for our purposes (especially since the pipeline is likely tuned to have adds take one cycle).
You can use Newton's method. Combined w/ constant time multiplication, division is only O(log N)
Newton's Method involves doing a division...
For #1, realize that this is going to greatly increase the data size of many applications. The larger the data size, the higher the chance of cache misses. In general, this is a loss, not a win.
wouldn't the chance of cache misses depend on the caching policy? How does the data size matter?
Data size matters because a program will typically access a fixed number of working variables, not a fixed amount of data. If a program's working set size stays at, say, 1000 words, and you move from a 32-bit to a 64-bit architecture, you need a cache with twice as much storage space to hold the working set without thrashing.
There's easily enough die area to double the sizes of the L1 and L2 caches; the problem is that it slows down cache access (more latency cycles fetching something from L1 is a Bad Thing).
Certain types of load work with constant size instead of constant word count, but most of those deal with working sets large enough that you'll thrash no matter what.
The gain with 64-bit processors is one of address space and nothing more.
Which includes better behaviour for those programs that have to fake larger address space. That would be a speed increase.
Nothing running on x86 will do that. Unless you're running old DOS programs in real mode, you're already working with a flat address space. Typically 2 gigs of this is available to user programs (with the rest being mapped to kernel or device space). If you have a problem with a working set larger than 2 gigabytes, you already have a Sun/$other_vendor machine to solve it on.
Larger address space targets the _future_ problem of desktop users who want many gigabytes of memory.
A fringe benefit is being able to more efficiently map multi-gigabyte files into memory space, but performance for this kind of task is limited by disk latency and controller bandwidth, not memory architecture.
For #2, realize that some integer operations are O(N) where N is the number of bits involved. 64-bit multiplication and division are slower than the same 32-bit operations. Period.
If area is not an issue, you can do a multiplication in log N steps. Current latencies suggest that this has been done for a while, so I wouldn't expect to see much of a difference at all for multiplying numbers. It's division that takes O(N) steps (you can apply brute force to reduce the proportionality constant, but the order remains).
2^64 addressing is not the only benefit of the change. FPUs see additional benefit when they have more bits. More bits means more precission; this is very important and desirable, especially when working with numbers that have fractional components. For proper 3D rendering, physics models, and anything else that involves computing numbers that have fractional parts, more is better. When the FPU can handle a double in one clock cycle because it works natively on 64-bit IEEE floating point numbers, you will notice a performance boost in addition to the increased accuracy.
Um, all current x86s already handle 64-bit IEEE double-precision floats natively (actually more like 80 bits, for "extended double-precision"). The FP register file has been this wide for quite a while.
There will be no performance or precision boost for floating-point math from moving the rest of the chip to 64-bit registers/datapaths.
Out of curiosity -- are there any digital media specifically designed for centuries of storage?
Punch cards. Especially if punched into UV-resistant plastic instead of paper, but even the paper ones will do.
Mill the text into aluminum sheets, hard-anodize the sheets, store in argon.
Guaranteeing storage in argon for 1000 years will get a bit tricky.
My favourite method: Paint in oxide suspensions on cloth woven from alumina (corundum), and then fire the pages and sew/bind them with alumina thread. The resulting book is resistant to physical wear and fire (the center of a bonfire would probably blur the letters, but that's about it), and is virtually invulnerable to chemical attack.
Look. The basic problem with space travel is real simple. Chemical propellants don't have enough energy per unit weight to do the job. As a result, all space vehicles are mostly fuel tank. They all have dinky payloads for their size.
The cost of even an unmanned launch is not dominated by the fuel cost. If needing a 20:1 ratio between fuel and cargo was the only hindrance, we'd be in the sub-$100/lb regime even with exotic fuels.
So, the theoretical minimum cost of chemical launch would seem to be quite low.
Incidentally, the "cheap, dumb booster" is a myth. Most of the cost comes from making boosters light. It's easy to make a cheap, heavy booster, but it will barely get off the ground.
So basically, we need cheap, light composites. We'll get there eventually (we have the "light" part, just not the "cheap").
While I'm not going to suggest that I, alone, constitute a control group, I can personally attest that since giving up TV in 1996 and radio in 1997 -- and I lived in Boston so no car, thus no billboards -- I now go into stores like Target (generally when someone I'm with goes) and it's, "nope, don't need that, nope, don't need that... All I see when I go, though, is people walking around, aimlessly, picking things up and sticking it in their cart. I used to be more or less just like them. The difference is beyond palpable.
My impulse spending has dropped too, and TV had little to do with it. It's called "growing up and learning to manage your money", and most of us do go through it as we age.
Car rims and the Abdominizer nicely illustrate that not _all_ people develop this level of self-control. However, even people without the self-discipline to not buy shiny things are limited by the fact that things like rent come _first_. Their disposable income is only what's left over after housing and food are taken care of, and that's not a lot (regardless of income level, usually; people tend to respond to a prolonged surplus by moving into a nicer place).
And as for the control group, I'm curious; which category does 21B (that's nine zeros) in credit card debt [news.com.au] fit into? The "neccessary" or the "increase in quality of life?"
It represents people paying for the privilege of buying things a month earlier than they otherwise would be able to. Whether that's a calculated expenditure or bad planning depends on the person.
Again, you fail to demonstrate that most income is spent on frivolities. And without that point, your argument just doesn't hold. Calling me names won't go further towards supporting your argument.
Here is a very logical and well written essay on UFO skepticism. [dabsol.co.uk] In particular, I would like to direct your attention to the section entitled, "Occam's Razor and the Skeptics", roughly two thirds of the way down.
[...]
What a debunker will do is mutilate and butcher the observations until it can be "explained" by one of the simpler hypotheses, which is the inverse of the proper approach. The proper approach is to alter the hypothesis to accommodate the observations. One should never alter the observations to conform with a hypothesis
This is true when observations are taken under carefully controlled conditions (that is, after all, part of the scientific method). However, chance eyewitness accounts of *anything* under non-ideal conditions are about as closely related to reality as a typical "inspired by true events" TV-movie. This is the bane of police officers taking witness statements from accident scenes; it also makes it reasonable to claim that any given interpretation in the memo was not a correct one, especially given that known phenomena almost certainly accounted for at least some of the items described.
This feeds back into the "extraordinary claims require extraordinary evidence" rule of thumb. If observations appear to contradict all expectations, and the observations are open to question, then it is fair to assert that the observations are likely to be at least partly mistaken. Note that this does not assert ironclad proof; only likelihood.
If you want guesses as to the other points you raise, sure, I'll give them; but without having been there that night, they're so much hot air.
Blind conjectures as follows:
The lighthouse hypothesis could explain a light appearing to move in the forest, but it doesn't explain how they observed what they described "as being metallic in appearance and triangular in shape, approximately two to three meters across the base and approximately two meters high." It doesn't explain how it could have "bank(s) of blue lights underneath".
Silouette of trees obstructing the light would do this quite nicely. Most of the light showing at the top, some glow at the bottom, and enough of a glow at the sides to give the impression of shininess. I can believe that the blue colour was an illusion; colour sense is royally screwed up in low-light conditions (light dim enough to be perceived as monochrome often looks pale blue or green). Without actually taking a look at this lighthouse, I have no explanation offered for why the pulsing light was described as red.
It doesn't attempt to explain why "the animals on a nearby farm went into a frenzy."
A meteor as bright as the full moon had passed overhead a few minutes ago. This is described in the link I cited. Or it could just as easily have been some other trigger; animal noise needn't be constant.
It doesn't explain how the object vanished and was spotted again "an hour later near the back gate."
Obstructed by trees as the observers moved would be my first guess. Other explanations doubtless exist.
it can't explain the relationship... ie WHY they recorded a "peak reading in the three depressions and near the center of the triangle formed by the depressions. A nearby tree had moderate (.05-.07) readings on the side of the tree toward the depressions."
That one's easy. Trees aren't radioactive. Any excess background was probably from rocks (my father had a few thorite samples at one point; drove a radiation counter nuts). Point the counter at a tree, and the tree blocks half of the background. Move so that you no longer have line of site to wherever the rocks in question are, or even move farther from the deposit, and you get a reduced count. Dirt will also do a decent job of blocking beta rays, as long as it's not itself radioactive.
It doesn't explain how "At one point it appeared to throw off glowing particles and then broke into five separate white objects and then disappeared." It doesn't explain how "three star-like objects were noticed in the sky. Two objects to the north and one to the south [which] moved rapidly in sharp angular movements and displayed red, green and blue lights.", or "The objects to the north appeared to be elliptical through an 8-12 power lens. They then turned to full circles.", or "The object to the south was visible for two or three hours and beamed down a stream of light from time to time." (Yes I know it mentions these last observations. Saying the above is "probably" just stars is NOT an adequate scientific explanation for these very specific and detailed observations corroborated by multiple eye witnesses)
You left out the part about the "red sun-like light" that pulsed and gave off the glowing particles observation being through trees, which means it could have been just about anything. Best guess: one or more people with flashlights checking out the site. A red pulsing light sounds more like a campfire, but wouldn't move.
I have no explanation for the distant lights observed on the horizon, but am confident that one of the many usual glowing-moving-light explanations applies.
So, in conclusion, the lighthouse hypothesis attempts to 'mutilate and butcher the observations until it can be "explained" by one of the simpler hypotheses'.
Per my comments above, I think that taking all of the observations at face value would be even less accurate, especially given the evidence offered that _some_ of them (the disturbance caused by the meteor and the lighthouse's pulsing light) are very likely to not be the result of spacecraft activity (as they were classified in the report). The scientific method includes acknowledging noisy data as such.
UFOSkeptic [ufoskeptic.org] a must read for all "science types", written by Dr. Bernard Haisch.
I'm afraid I'm not terribly impressed with this site. After reading through these documents, it became clear that Dr. Haisch has a habit of jumping to the most favourable possible conclusion given incomplete evidence (as opposed to saying "the evidence is incomplete; here are the options and we don't know which is true").
The most thought-provoking case of this was his discussion of Fermi's Paradox. The paradox is that observations to date suggest that there are a very large number of worlds in the galaxy hospitable to intelligent water-based life, and yet we see no evidence of it and none of it has provably come to visit. Dr. Haisch notes that this either means that colonizing civilizations don't last long, or that aliens _do_ come to visit, and immediately concludes the latter. If anything, the lack of strong evidence of visitation or beacons or the like suggests that the former case is the more probable.
As a side note, the implications of this chain of reasoning are fascinating to consider. Either civilizations almost inevitably eradicate themselves, or they almost inevitably become permanently introverted, or they almost inevitably move somewhere else (either a virtual world, a la "Calculating God", or another universe (a la the Sublimed Elders from the "Culture" novels). Another option is that even under favourable conditions, sapient life, or perhaps complex life of any form, is extremely rare. Yet another option is that there is some other factor affecting habitability of worlds that we haven't found yet that eliminates most from consideration.
Whatever the case, there is by no means convincing evidence for the conclusion that aliens must be visiting us. Yet, the whole site is filled with jumps of logic like that.
What about redesigning the shuttle to launch from a maglev accelerated platform, which might be able to lift it to LEO, then fire internal engines or external rockets to leave the atmosphere. Electricity sure is cheap these days.
Firstly, LEO is already outside the atmosphere, so your second phase makes little sense. You'd actually just be doing a course correction (any initial ballistic launch trajectory would be an orbit that intersects Earth's surface).
Secondly, you'd have serious problems keeping the gun from destroying itself on firing. If you have air in the barrel, the coils, rails, or what-have-you have to deal with a mach-25 sonic boom at ground zero. If you don't have air in the barrel, you have to figure out how to keep an aperture the size of the space shuttle open while allowing no air to pass through it (actually, forcing air to flow *out* of it, if possible). This is possibly do-able with extremely strong jets of air beside the aperture.
Thirdly, your gun will be tens of kilometres long if it fires cargo, and thousands of kilometres long if it fires manned craft. Acceleration must be low enough not to damage the cargo, and you have a lot of delta-V to build up. A cargo gun would have to be vertical or near-vertical; the turning radius at reasonable lateral acceleration is larger than the gun. So, you have to build a 10-km tower. The manned gun would have to be a nearly-flat ramp ending above most of the atmosphere, because a human-safe lateral acceleration requires a turning radius that is again longer tham most of the gun.
In summary, even a cargo-rated magnetic cannon is likely to be impractical to build.
The "super gun" is a special case, as it can sustain a substantially stronger acceleration than a magnetic cannon. However, it too is huge, and a space-capable version has not been demonstrated to my knowledge (just sub-orbital capable). You also run into serious materials problems scaling it up to accept projectiles the size of even an unmanned shuttle (you're stuck with very small cargo capsules).
Lastly, while electricity is cheap, building a very large launch facility isn't. Your construction cost gets amortized into the launch cost, over the maintenance lifetime of the facility (plan on an amortization time of at most 10-20 years). This problem is an important one for laser launching facilities and space elevators, too (my own calculations show that you'd need _extremely_ high ascent speeds on an elevator to move enough cargo to keep the launch cost below even current costs).
Food for thought. I'm honestly not sure if we'll see a practical replacement for chemical rockets this century (elevator is the best candidate, and it'll be quite some time before materials production matures and other problems are solved).
Furthermore, I think it's a bit dismissive in this case to call it "just some object in the air", like it could be a weather balloon or swamp gas or something. This is an object that moves and behaves like no known terrestrial phenomenon.
Except a light house.
Someone had the common sense to go to the event site and look in the direction indicated by the report. Must have been a really cool-looking incongruity if you didn't recognize the illusion.
Advertising works because it makes a hole that you now need to fill with the product in question. It tells you that you stink, you're stupid, you're abs aren't trim enough, that you aren't dating someone cute enough, that you'd be OH SO MUCH HAPPIER if you could just get that new Lexus,
[...]
For you to argue that runaway consumerism doesn't exist is to argue that advertising does not work
By and large, it doesn't. When was the last time you paid attention to commercials, online or in conventional media? Do *you* have a burning need to buy that Lexus or palm-pilot or to drink Pepsi because the artist-du-jour told you to?
Advertising influences _what_ people buy quite strongly (by building brand awareness), but not so much how much they spend on buying things. It represents corporations slugging it out with each other to make sure that the money that will be spent, will be spent on them.
A high-tier executive may spend most of their money on frivolous items. The rest of us spend most of it on things that are necessities (rent/mortgage, food) or things that do substantially increase our quality of life (getting a car instead of using public transit, eating a fancy meal, going to a movie).
Your argument that we'd be much happier making half as much money and kicking our "addiction" assumes that most of our money is spent on things that do not contribute to our happiness. This does not appear to be the case for most people.
Thus, your arguments do not seem to apply.
I think that's sarcasm.
Well, four moderators thought it was informative
It was.
It correctly pointed out that Russia wasn't the only entity hindering the space station's development.
Support for new instruction set extensions like SSE or MMX could be added with a simple firmware upgrade. A new code-morphing frontend could turn the Crusoe from an x86-compatible chip to a PowerPC, MIPS, or SPARC-compatible chip in seconds
This turs out to be much more difficult than it first appears. There are a number of low-level architectural features - especially in the memory interface, but elsewhere too - that are very difficult to emulate if you've built a processor using different assumptions. This means that while you might be able to emulate a PPC/MIPS/SPARC on a Crusoe - or even on a PC - by dynamically recompiling code, the only architecture that would perform well would be one with a good match to your actual hardware. The original Crusoe chips were designed from the start to emulate Intel processors, and this new chip is presumably in the same boat.
maybe the human race itself will survive, but it will most likely not be sufficient to maintain itself, and will just die out anyway.
As long as the destination environment isn't hostile, you don't need very many humans to survive (the 50/500 rule for breeding populations).
If you require an industrial base - e.g. if you were colonizing a hostile environment and needed habitats - the size of a small city would still be fine. What is the smallest community that can be self-sufficient industrially?
In summary, I think that making colonies that are viable in the long term does not require an unmanageable starting size or resource base.
I think that the technology/knowledge to create birth control pills for men has been around for a while. I imagine they will be much safer, too, since sperm is manufactured on a frequent regular basis, the pill would just have to affect that process.
Wrong on pretty much all counts, actually.
Stopping ovulation in women is straightforward - you're trying to stop a once-a-month event, and the female body already has a shut-down mechanism built in (ovulation stops during pregnancy). The pill just triggers this mechanism (tricks the body into thinking it's pregnant).
Men are designed to produce sperm all the time. There is no built-in shut-down mechanism to trigger. You also have to stop production of *all* of the hundreds of millions of sperm cells produced between sexual encounters, as opposed to stopping just one egg from being released. A male contraceptive that eliminates 99.9% of sperm production is still useless.
And because you're trying to inhibit a function that's never normally shut down, you have to start from scratch when figuring out how to do it, and live with the fact that a male contraceptive that's 100% effective runs a real risk of causing permanent damage if not very carefully designed.
It could probably be taken as little as 24-36 hours before sex to have its effect, and it would most likely not affect hormone levels.
Hormone manipulation is just about the only way to affect sperm production. What do you think drives it? Hormones are the body's signalling system for stopping/starting body processes.
It's only now, after decades of research, that relatively safe, reasonably effective approaches to male contraception are being developed, and we have a long way to go before they're mature.
Seriously. If privatization of space continues to grow, and launches become more afforadable, I'm predicting we may see businesses offering to launch your media into space, where the only thing that will destroy your data is the occassional asteroid collision.
The problem with, say, backing up to a satellite full of drives (or even just launching a box of tapes or CDs) is that most media will degrade quite quickly in space. You're bathed in enough ionizing radiation to make electronics go funny every few minutes to every few weeks, and that's when there *isn't* a solar flare going on. Magnetic and optical media are more resistant to radiation, but are far from immune. Think of this as being put under an airport x-ray machine for as long as it's up there.
Multiple earth-based sites gives much better reliability.