One IDE channel. No floppy, serial, parallel, or PS/2 ports. Kill IrDA support.
The problem is that virtually none of this saves money.
Legacy support costs virtually nothing. The only expensive parts are the connectors (the interfaces are all integrated: if you want IDE at *all*, you basically get everything else) and you can just put them on a pin header if you want.
IrDA, serial, and PS/2 are all the same thing - parallel, floppy, and even IDE are usually supported on one chip. They're so cheap that there's no point not to put them on. For one thing, they're useful enough to the people testing the board that they earn their keep just that way.
The CPU and RAM chips could be soldered onto the board. Bundle it with a cheap mass-market OEM hard drive, a case with a 40W power brick, and you've got a PC.
RAM prices fluctuate too much for this to be succesful. CPU integration makes sense, although again, the price drops quickly enough for you to be left with a platform that's far overpriced in just a few months. Keep in mind, that's one of the main reasons you don't integrate the CPU and memory - price concerns.
For one thing, in the time it takes the system to get to market, the board will be a bit overpriced/underpowered for its price point. Systems that have socketed CPUs/memory are viable on the market for a long enough period for people to sell off their supplies.
The way you make a cheap motherboard is to only use the integrated peripherals in the southbridge, and then volume, volume, volume.
Thankfully, the light truck (SUVs, basically) exemption was lifted in 2001: in 2005-2007, the minimum goes from 20.7 to 22.2. Not wonderful, but nice.
Blah, missed the fact that this only applies to vehicles under 8500 pounds. This includes *some* SUVs, but not all. Apparently the "over 8500" category is only ~10% of the total number, though. So many SUVs will be improving in fuel economy.
As for the US, you have the CAFE act. the point is that light trucks are exempt, so the car producers push for those. Ironically, they have grown popular even here, where this kind of loophole is neither existent nor necessary. BUT, over 70% of the Ford mondeos sold here are diesel cars.
Thankfully, the light truck (SUVs, basically) exemption was lifted in 2001: in 2005-2007, the minimum goes from 20.7 to 22.2. Not wonderful, but nice.
The funny thing is that people in the US treat government regulating mileage as if it's never happened before, completely forgetting CAFE and the rise from an average of 14 mpg to 28 mpg. The amazing thing to me is the fact that Congress hasn't pushed it up since 1990, especially nowadays with the price of gas going upwards, exactly as it did in 1974.
But, then again, the current administration in the US has no intention of lowering the US consumption of oil - just the price. Oh, it's not like they care about the price consumers pay - but the price that companies pay, now, that's different.
See, I think this might be the reason for why I might appear so adamant - I was born, raised, and live in the US. Gas prices, in dollars per gallon in Italy, in February 2004, were $5.04. In the US they were $1.64. That's about 1/3 to 1/4.
Economics does in fact work (as I'm sure you know) - higher prices means less demand, and cars with better gas mileage are far more common in Europe. Heck, diesel is far more common in Europe than in the US, and even pushing for an increased diesel adoption in the US would be better, because diesel engines on average have 20% higher gas mileage than gasoline burning engines. Diesel adoption in the US should go up in the next few years, but given the spike in oil prices, I really would've expected federal laws to start being enacted to push diesel adoption faster. It's a great stopgap.
But the US is pushing the world faster towards mass chaos, and so for me, I look at my country's laws and trends, and I say "what the hell are you doing??" I look at other countries, like Europe, and I say "hey, if the US had the same policies the rest of the world did, we'd be fine." Really - the US is pushing for OPEC to accelerate oil production rates (in other words, pushing us *faster* towards the Hubbert peak) so they can have cheaper gas.
I mean, I drive a car from 1993. It gets 25 mpg city/35 mpg highway. This is advertised as very good gas mileage in the US nowadays on new cars! (In fact, if my car was sold today, it would be one the top 10 best gas mileage cars) This is insane - we've known how to build that kind of an engine for years. That's not 'good' gas mileage. It's average. In fact, it should be the minimum gas mileage sold for new cars nowadays.
The main problem I have with people dismissing global warming is the fact that CO2 emissions (hell, emitting anything into the atmosphere) isn't a long term strategy. Even if you don't think global warming is real, it's still smart to reduce CO2 emissions. Every other country in the world seems to recognize this except the US.
A large portion of the problem is the fact that in the US, we have politicians that can't seem to grasp the fact that just because someone says "oh, and this will help cut down on CO2 emissions, which aids global warming" doesn't mean that you can say "I don't agree with global warming, therefore I don't think what you're saying is reasonable."
If people don't believe that CO2 can cause global warming, they're idiots - and they've never gone inside a greenhouse. But seriously, I think that's what many politicians in the US think!
If you think "OK, I don't agree with this model", that's fine. That's logical, in fact. We can debate what the warming rate as a function of CO2 in the atmosphere is. Sure, no problem. But all that should do is mean that we're arguing about how fast we should be reducing CO2 emissions, not whether or not we should. And again, you look at the US - and it seems as if the current politicians do want to believe that we don't need to reduce CO2 emissions at all! There are very few policies in place to really start lifting the gas mileage of cars in the US - hence the reason that the average gas mileage of all vehicles in the US went *down* for about a decade. Down!
Sigh. So that's why I might seem so adamant - it seems like in other countries, if you say "well, I don't believe the global warming models" you're simply saying that we don't need to cut CO2 emissions amazingly fast. In the US, if you say the same thing, you're saying that we don't need to cut CO2 emissions at all. And that's just crazy.
If the term is long enough to cover several millenia, a plan for it, that begins with a few centuries of mere discussions, is a perfectly good one. Aggressive even...
OK, the whole "multi-millenia" thing was just to point out that even if you throw out running out of fossil fuels, and any possibility of global warming or environmental effects, you still have to cut down on CO2 emissions eventually, so, in the long run, it's still a good thing.
The end of fossil fuels and environmental effects are not multi-millenia effects. They'll show up in this century.
Besides, what do we need discussions for? The proper replacement for fossil fuels (and thus, cutting back on huge amounts of CO2 emissions) has been around for a while now. Replace most of the oil-burning/coal-burning/gas-burning power plants with combinations of nuclear, solar, wind, and hydroelectric plants. As a stopgap, introduce hybrid cars, and begin introducing a fuel cell based infrastructure, with hydrogen generation from either fossil fuels (temporarily) or electrolysis (in the long term).
Keeping the power plants, and continually building more oil-burning cars, only exacerbates the problem. Every dime you spend on those power plants to keep them alive for a longer period of time is foolish - they won't be profitable for an infinite period of time, so you shouldn't be planning on keeping them around for an infinite period of time. Likewise, the constant introduction of oil-burning cars is also foolish - those cars won't be affordable to drive over their lifespan. Most people, when looking at hybrid cars, for instance, look at the initial cost, and then say "well, I'd have to save $X each month to pay for it, and gas isn't that expensive." The problem is that they're neglecting the fact that gas prices, in the long term, must increase.
The other point regarding cars is the fact that it's extremely important to push hybrid cars into the market, because the new car sales are only a portion of the total car market - you need to get hybrid cars into the used market, rapidly. Tax credits for sale and purchase of hybrid cars would do this quite well. Plus, the increase in the number of hybrid cars would mean that more people are spending less money on gas, a portion of which goes overseas. So your trade deficit goes down, and from a government perspective, it's not only affordable, it's long-term beneficial.
The fact that certain people say that the cost is too high shows that they clearly don't understand the problem. The longer the fossil fuel plants and oil-burning cars operate, the more rapid the replacement plan must be, and the more expensive the plan must be. The sooner you start, the slower you can take the replacement plan. Simply require that power companies replace some fraction of their fossil-fuel burning plants with clean plants each year. Require that car manufacturers sell an increasing fraction of hybrid cars, and at some point start phasing in fuel-cell based cars.
The sooner it's done, the cheaper it is. And the less the consumer, and the companies will complain. In addition, the faster these companies switch off massive fossil fuel consumption, the longer the oil companies will be able to survive. It's just procrastination and short-term profiteering that's preventing it right now. It certainly isn't lack of sufficient motivation.
From this explanation. Twin A stays on Earth and Twin B sets off in a spaceship going 0.995 c (time and space will dilate to 1/10th). He reaches a point C that is 9.995 light-years away and heads back at the same speed. Let's assume accelleration is instantaneous. When Twin B leaves earth, both twins agree their clocks read zero. When Twin B reaches point C, Twin A sees that his clock reads 10 years and Twin B's clock reads 1 year. Twin B thinks his clock reads 1 year and Twin A's clock reads 0.1 year. As soon as he turns around, Twin A still thinks B's clock reads 1 year and his clock reads 10 years, but Twin B thinks his clock reads 1 year and Twin A's clock reads 19.9 years.
Sigh, all I ever hear are bad explanations of the Twin Paradox. Let's be clear - there's no need to invoke General Relativity to explain the Twin Paradox at all. It clears a few questions up, but you still don't need it.
Here is a great explanation using only Doppler shifts, which most people understand quite easily.
The problem that you have is that you're assuming that Twin A sees Twin B reach Point C at the same time that Twin B reaches point C - he doesn't!
From Twin A's frame, he sees Twin B leave at year 0. He calculates twin B arrive at point C at year 10, but he can't see twin B arrive at point C until the year 19.995, because any light signal from point C won't arrive at Twin A before then! Amazingly enough, in the 0.005 years before Twin B arrives home, all of the images of Twin B for his entire trip home arrive all in a bunch! They're all massively blueshifted!
So Twin A sees an outbound leg that took 19.995 years for all of the images to arrive, and an inbound leg that took 0.005 years to arrive. For Twin B, this isn't true - for the outbound trip, he sees Twin A age at 1/10 the speed, and when he arrives at Point C, he's only seen Twin A age 0.1 years. On the way back, however, Twin B will see Twin A age just as rapidly as Twin A sees Twin B age in the last 0.005 years - but he'll see it for an entire year! So Twin A ages far beyond Twin B, and they will both agree that Twin A is older.
There's a terrific spacetime diagram showing this here.
"Simultaneous" is meaningful in special relativity; it just depends on the reference frame.
I was clarifying, not disagreeing, with the simultaneous point. The definition he gave for simultaneous was basically correct well before special relativity, and didn't much change with special relativity. If you define your "dt" as being "the time from when the light emitted from when event 1 struck my eye to when the light from event 2 struck my eye", then even in classical mechanics, "simultaneous" depended on your reference frame. The difference was that previously there was always a presumption of the 'ether' frame, which was an absolute time reference, and relativity destroyed that.
So "simultaneous" really doesn't mean anything different in special relativity as it does in classical mechanics.
Proper distance, however, didn't exist before special relativity, and is very important in relativity. Two events with a timelike separation, for instance, can never be simultaneous in any frame. Two events with a spacelike separation, though, are always simultaneous in some frame.
The concept of "absolute time" really was what people thought of when they talked about "simultaneous", because they were talking about the absolute time separation between two events, and that concept really was shattered by special relativity, and that concept of "absolute time" (and "absolute spatial separation") was replaced by proper distance.
The part I (clearly) disagreed with was the part where he said that observers need to be tied to a frame for their observations to be useful. This isn't true, and it isn't the point of special relativity. The point is that things that we thought were invariants definitely weren't, but there are (new) constructions that were invariant. The "frame dependence" issue is far less important than the definition of the new frame-independent quantities, which led to quantum field theory.
..It seems to me that you are implicitly defining "reason" in contemporary terms.
Um. Yes?
Half the point of developing tools like the scientific method and analytical reasoning is so we can use them. As the methods become more refined, our trust in them should increase.
Thus, I should have more trust in scientists' results than a person in the year 1000 had in a fearmonger spouting off.
I would have liked any model to appropriately "explain" temp changes in the past: for example, average temps here in Italy have had significant swings in historical times when human activity, espacially CO2 related, can be assessed as varying between "negligible" to "nonexistent". As you see, no predictive content is required, only a "best fit".
Er... yes, of course, temperature variations have swung significantly in historical times. Temperature variations do happen over time - quite significantly. A large part of the warming over the past 1000 years is due to the eccentricity of the Earth's orbit decreasing (as it periodically does). We're definitely in a warming trend right now, just from natural causes.
But the CO2 levels are not from natural causes, and they're massively above what they've ever been in several hundred thousand years of data. See here to see what I mean: note the graphs showing the trends over time. Yes, we're in a natural warming period right now. But also note the scale of the CO2 graph - 175 to 300 parts per million, total variation.
Now look down at the graph at the bottom - that's the current trends on CO2 levels. Note the scale again - 280 to 340, and sharply rising currently. We're now about 10-15% above the highest levels of CO2 ever seen in the atmosphere, and it starts climbing almost exactly at the Industrial Revolution.
No one's trying to suggest they understand the atmosphere perfectly. Trying to explain the temperature rise, in my opinion, is also quite arrogant. But they certainly understand it enough to claim that a massive rise in CO2 will likely cause climactic effects, and they are certainly correct that we cannot simply continue pumping CO2 into the atmosphere at the present rate.
You are perfecly right in saying that CO2 is a earth warmer, and reducing that could impact; but what if it is later proven that it's all in the sunspots cycle, or other things?
Well, that's science - then the models were apparently wrong. But you're not asking what happens scientifically. You're asking how does that impact socially. And I'm presuming you mean to say "what if it is later proven that it's all in the sunspot cycle, and we reduced CO2 emissions for nothing?"
The answer to that is simple - no matter what, we have to reduce CO2 emissions eventually, because we can't keep burning oil/natural gas/coal forever . Since fossil fuels are the main cause of CO2 emission, reducing fossil fuel usage and reducing CO2 emission are the same thing. The cost will be the same (in inflation-adjusted dollars) at any point in time. We know how to do it now - we replace oil burning cars with hydrogen fuel cells, we replace oil/coal/natural gas power plants with nuclear/solar/wind. We can actually make it cheaper if we start now, and amortize the cost over 50 years, rather than doing it in 10 when the need is more obvious. As a bonus, the world will still have a large supply of cheap fossil fuels for many centuries to come after that. Fossil fuels, after all, have a good power density.
I'm not suggesting stopping fossil fuels now. I don't think anyone is. I think everyone is suggesting we start to stop using them, and by that, I mean regulations. I really find it insane that the US walked out on the Kyoto treaty. It's obvious to anyone that the world eventually has to stop emitting more CO2 than the world can handle. The only question is "how fast", and the US simply walked
If the atmosphere were a great scatterer of visible light, that's exactly what you'd get.
No, if the atmosphere were a great wavelength-independent scatterer of visible light, that's what you'd get. As it turns out, the sky is not blue because the sky scatters blue light most effectively - the sky is blue because the Sun is blue. Blue-green, to be specific.
If the Sun was a uniform source of light, the sky would be purple, because the sky scatters purple light most effectively. If the sky scattered light tremendously, it would look white, but that's simply because our eyes have saturation limits. If you did spectroscopy on the sky, it would still be purple.
Rayleigh scattering is strongly dependent upon wavelength. That's why the sky looks blue.
And as for that odd white fog you talk about, there seems to be a ton of it covering me right now. They call them clouds - and they cover 60% of the Earth's surface on average. Which is also another reason why changing the surface albedo doesn't necessarily change the temperature of the planet in the simple way that you might think.
We currently are raising CO2 levels in the atmosphere by 2 parts per million per year.
We eventually have to be raising CO2 levels in the atmosphere by 0 parts per million per year.
That was the entire point of the statement regarding suffocation. Many people say "we shouldn't cut back on CO2 emissions - it's too costly." My point is that fundamentally, we have to.
Aha, now we are switching the subject slightly from CO2 emissions to oil shortage.
No - I included oil burning because oil burning is a major source of CO2 emissions. Cutting down on oil burning (without replacing it with a new form of CO2 emission) is cutting back on CO2 emission.
And note that I never talked about an oil shortage. I said the peak oil production.
An awful lot will change -- we may have cold fusion and interstellar travel by then.
Basing policy decisions on the possibility of future breakthroughs is not a solid long-term plan. It is far more efficient, and prudent, to begin the change gradually, and then, if the change is later deemed unnecessary, roll back the changes.
we were supposed to run out of the stuff already.
I'm not talking about running out of oil. I'm talking about oil production peaking. And when oil production peaks, the price will not go uniformly up, because demand is linked with price (also known as a feedback loop). Instead, the price will fluctuate wildly. Read here for more. Don't suggest that people have been predicting the end of oil reserves for years. They haven't. Hubbert predicted the US oil production would peak in the 1970s. It did. That led to a very volatile period in gas prices in the US.
start we start sacrificing now for the sake of our future great-great-....-grandchildren thousands of years from now are not at all convincing.
Managing current resources for future needs is the responsibility of any government. It is, in fact, one of the chief reasons we have governments. There is a phrase for people who ignore long-term problems for short-term gains: we call them "short-sighted." It's generally considered derogatory.
Because they hope, it may get them elected.
It might also have something to do with the fact that oil concerns are driving foreign policy. The US is dependent upon foreign oil. This is a liability, just as any 'debt' is a liability. Both candidates (and, I imagine, a huge majority of citizens, economists, and scientists) insist that it is a good idea to eliminate dependency on foreign oil.
So, if we A: need to cut back on oil consumption very soon, B: have reason to believe that CO2 emission (mainly from oil) also needs to be cut back, why don't we do both if the cost is only marginally higher than doing one alone (which it is)?
Because both require very expensive solutions to something, that is not even problem. At least, not yet -- unlike, say, cancer, terrorism, AIDS, budget deficit, malaria, and obesity.
1: There will always be current problems right in our face that seem more immediate. That does not mean that a long term problem cannot be more severe and require just as much attention.
2: They both require the same solution! It's efficient to tackle both problems at once, rather than develop something that fixes one problem and leaves the other. You'll end up spending more money in the long term.
Change always is expensive. That doesn't mean that it isn't profitable in the long term. Given the huge amount of money that's flowing out of the US for foreign oil, I can't imagine that any cost/benefit analysis for any reasonably long period of time for the US would suggest continually burning oil. It's a losing position.
And it's interesting that you mentioned the budget deficit, as it's also linked to these problems, because we have such a huge amount of money flowing overseas to buy oil. If we cut back on burning oil, in favor of locally generated power sources, then that money stays here, and the trade deficit goes down. And then the budget deficit goes down as well.
In relativity, "simultaneous" means an event occurs at the same time in the same reference frame.
Actually, no. In relativity, "simultaneous" doesn't mean anything. That's half the point.
Before relativity, we had several ways of describing causality - we could say that "event A happened before event B", "event A happened at the same time as event B", "event A happened after event B" - and those definitions seemed absolute, just like the distances between objects were absolute - the distance between point X and point Y was D.
But relativity changed that.
That's because the notion of the "temporal distance" between two objects (that is, "dt^2") isn't invariant between reference frames. Neither is the spatial distance (that is, "dr^2 = dx^2 + dy^2 + dz^2").
any observer must be assigned to a frame for his observations to be useful.
That's the part that's a little wrong - see, there are several invariants - things that are the same in all reference frames - in relativity. Specifically, the proper distance, or "ds^2 = (cdt)^2 - dx^2 - dy^2 - dz^2". In *every* reference frame, that quantity will be exactly the same. So you can speak of quantities without reference frames. I can say that the proper distance between the point and time at which a photon from a lightbulb was emitted to the point and time that my eye registered it is zero - and every observer would agree with me.
So while before we could say "before, simultaneous, after", we now can say "spacelike, lightlike, timelike" - if the proper distance is less than 0, equal to 0, or greater than 0. In *any* frame, those measurements will stay the same.
It's important to recognize that relativity doesn't say that *all* measurements are subjective. Of course it doesn't say that - the speed of light, for instance, is the same in all frames. What it does say is that a lot of the quantities we used to measure are subjective - specifically, spatial and temporal displacement, momentum, and even things like electric and magnetic fields. Those are relative - but there are quantities underlying them which are invariant.
Why mandate anything now, when both the technology is still expensive, and the need is far from obvious? By your estimates, we can safely wait another 3-7 thousand years, and if our kin does not have the right technology by that time, than may be they deserve to die out.
It's utterly amazing that you read everything that I wrote, and missed the point entirely.
We can't wait 3 to 7 thousand years. I never said that. I simply said that it's insane to even consider that we can continue pumping out CO2 indefinitely. We can't. No one could possibly suggest that we could. 10,000 years is still less than infinity. That's all that I meant.
Since we have to stop sometime, that means we have to begin stopping at some point as well. If we don't do it soon, we're just putting it off, and we're going to make the rate at which we have to cut down on emissions much, much higher.
A simple cost-benefit analysis suggests, the resources can be spent on something much more useful.
No, it doesn't. We're clearly approaching the peak of oil production in less than 100 years. We can either continue the way we are now and change very violently in fifty-sixty years, or change gradually now and not wreck the world's economy.
Why do you think people are talking about "reducing our dependency on foreign oil"? Why don't we tackle both problems at once and reduce CO2 emissions as well? Why risk it?
I think one way to inoculate oneself against this disease is to become aware of the trigger words and phrases, which seem to act as vectors for the disease. Words and phrases such as Liberal, Tax Cut, Tax Cut for the Rich, Terrorism, Spreading Liberty and Freedom thru the World and many others are used to turn of your capacity for analysis. But we can reprogram ourselves to respond to such triggers with increased skepticism and increased vigilance.
Actually, I've decided that if anyone comes to my door and tries to spew rhetoric that's demonstrably wrong, and clearly doesn't know what they're stating (say, someone saying that Kerry is the "first-most liberal senator in Congress", for instance, and then not knowing over what time period that was considered to happen) I'm going to get my jacket, follow them around with my laptop and wireless internet connection, stand behind them when they go to people's doors, and show the people the truth.
I actually don't mind if people spew rhetoric that's spun slightly that they know the truth behind. There are many ways to present data, for instance - I don't begrudge Bush for saying that he increased the number of Pell grants - he did - but then Kerry is perfectly fair to point out that he cut the total amount of money, as well. Some people might think that it's more important that more students get money, even if it is less - not me, of course. I've gotten Pell grants. I know how important that money was.:) What I hate is when people don't even *know* the truth behind the spin.
It's like 'whisper down the line' - if you know the beginning of the whisper, you will only distort the whisper so much. If you don't, though, then you can end up incredibly far off from the truth.
We have no idea what the average is. What if we are coming off of a 5,000 year low cycle?
Um, then the predictions are wrong, and we'll find out. That's science!
Now, if you're trying to use this to justify policy, that's a different point. After all:
We have to reduce CO2 emissions eventually anyway - we can't simply continue to do it. We'll run out of fossil fuels, or if we're really stupid and find a way to continue emitting CO2 at current levels, we'll kill ourselves in 10,000-20,000 years or so from too high CO2 concentration.
The downside to reducing CO2 emissions earlier than needed is that we have to "bite the bullet" in dealing with finding a new energy source earlier rather than later. It does, however, mean that we still have relatively economical fossil fuels for some time to come.
The downside to reducing CO2 emissions too late could be serious environmental repercussions, which we can only speculate about. Likewise, the downside to cutting back on fossil fuel dependence too late is serious economic repercussions from demand exceeding supply.
We already have several technologies which can replace fossil fuels - they aren't quite as cost effective currently, and questions exist as to whether or not they can scale, but they do exist.
If you approach the problem logically, we're fools not to start cutting down on CO2 usage now and start phasing in newer, cleaner technologies (mandating hybrid cars, pushing towards non-fossil fuel power plants, etc.).
We have to do it eventually. There are little downsides to doing it too early, and in fact, several possible positives. There are many possible severe downsides to doing it too late.
Essentially, Earth's societies are procrastinating. We have to do it eventually. We just don't want to start doing it yet. This is naive, and quite dangerous.
The problem with some people who worry about global warming is that they have a tendency to say that severely reducing carbon dioxide emissions is the only way to prevent disaster- and while that's a lovely sentiment, it is excessively impractical.
Fundamentally, humans must cut back severely on carbon dioxide emissions eventually. We're obviously pumping more CO2 into the atmosphere than plants can handle (hence the reason that the CO2 level is going up at all). If we continue at the current rate of emissions, then eventually, the atmosphere will be primarily CO2. Currently it's +1-2ppm/year. In 100,000 years, CO2 would be 10-20% of the Earth's atmosphere, and we would all die.
And this is assuming that the rate of CO2 emissions doesn't increase. It, of course, currently is increasing.
Obviously this won't happen - fossil fuels are the primary culprit, and we don't have enough of them to continue for 100,000 years.
But that just reinforces the point - we have to severely reduce CO2 emissions eventually - either by choice or not. So why not start now? For one thing, it would ensure that fossil fuels (with their conveniently high stored energy density) would be usable for more irreplaceable needs.
Or we could just continue blindly burning fossil fuels until we hit the peak oil consumption, and watch the entire world's economy go haywire.
"The end is near! repent ye sinners!", and remember: they were in good faith.
No, it wasn't in good faith. They had no reasonable belief to assert such a statement. If they said that, it was self-serving fearmongering (or paranoia).
unless these climatologists present a viable climate model by which changes in human activity determine the climate, they have the same credibility, I'm afraid.
What's a "viable climate model"? One which explains all changes to the climate and predicts all weather perfectly? That's never going to happen - ever. And it's not needed, either.
For the same reason that biology can't produce a viable model based on fundamental theory for the way that organisms act, meteorology can't do it either. Biology can (and do) formulate hypotheses and theories based upon phenomenology, and use those to predict. They are more correct than they are wrong.
In exactly the same way, climatologists can use formulate hypotheses and theories based upon empirical data - that is, historical data about the climate record - and use it to predict current data.
Saying that they have to have a perfect climate model is ludicrous. And comparing them to fearmongers is also ludicrous.
This is simple, freshman physics we're talking about here.
There's also no doubt they're right that CO2 warms the atmosphere, as well. If you triple the amount of CO2 in the atmosphere, it's going to warm up. We also know this from observations of other planets' atmospheres. Anyone who runs a greenhouse knows this. We've now increased the CO2 level by 25% - higher than ever seen in ice core data. Our CO2 output is still increasing, which means that CO2 levels in the atmosphere are still increasing. At some point, the increased CO2 will increase the global temperature. It's not a question of "if". It's a question of "when".
No reasonable scientist could possibly believe that we can continue dumping CO2 into the atmosphere indefinitely. So it's obvious that at some point we *do* have to curtail atmospheric CO2 emissions. Why put it off?
CO2 is transparent to visible light. CO2 cannot prevent the reflection of visible light at the surface back out into space.
You're presuming that visible light incident upon the surface of the Earth produces the Earth's global temperature.
This is demonstrably wrong. In fact, you can relatively easily calculate the Earth's temperature if this were true. It's called the blackbody temperature: here is a description.
Earth's atmosphere is in fact specifically responsible for absorbing a large portion of the reflected light (it scatters visible light quite effectively - hence the reason that the sky is blue. some of that scattered energy goes into the atmosphere as heat). If it wasn't, Earth's temperature would be below freezing. Changing the overall albedo of the Earth may or may not have the intended effect. It's in fact quite complicated, as the atmospheric scattering depends quite strongly on wavelength.
Then the other problem is that if we do do this, and it does work, we've essentially increased the temperature dependence of the atmosphere on the solar input, which means that the time dependence of temperature would go up dramatically.
He has been mean to guests, but it's only when they come on and try to treat it as a news show - that is, by giving meaningless talking points.
Best one was when a guy came on and said "well, Kerry's the first most liberal senator" at which point Stewart popped up and said "who said that?" and the response was "Well, they come up with this compilation of votes..." and he responded "Who is 'they'?"
He did this over, and over. That is what Stewart hates, and I agree with him. He hates talking points. Today's media is 20 seconds of fame, not 20 minutes of fame. You say one phrase, and it sticks with you - take Bush constantly quoting Kerry's "global test" regardless of the fact that he never used it in the way he meant it. (He said our actions must pass a global test, not that our decisions must be decided by a global test. This is akin to saying "I would like to beat you to a bloody pulp, but that would probably make society throw me in jail.") or Kerry constantly using figures that are bloated out of context for effect.
God, do I agree with Stewart. I can't watch the news anymore. They're not journalists. They're microphones for politicians, and that's all. It's why I watch the Daily Show. Now I know, for instance, what that "first most liberal senator" thing means. And I know that the Republicans will beat people over the head with it, and I know that they don't even know what they're quoting! The same is true for Democrats, as well (God, I've heard enough Democrat rhetoric to make me sick).
What's interesting is that most Republicans tend to avoid talking for 'real' on the Daily Show, and so they get beaten up a little. Democrats seem to understand that Stewart won't let them pull the 'talking points' thing. Certain Republicans understand - McCain, for instance, or the head of the RNC who was on.
In practice a multi-core is slower than separate, because they have to share the same bus to main memory. Well, at least in my experience with the POWER4, that is.
I'm only tangentially familiar with POWER4, but it seems like the bus speed isn't high enough. So long as the bus speed exceeds the bandwidth of the memory controller by a significant margin (and the chips didn't have onboard memory controllers + their own memory like the A64), I don't see how, in practice, it could matter.
For a Pentium 4, for instance, it will be faster, because *all* multiprocessor architectures are shared-bus topologies, so it doesn't matter if there is one set of wires that multiplex inside the chip, or two sets of wires that multiplex outside the chip. It's still a shared bus.
For an Athlon 64, it's faster than a multiprocessor solution in which only one CPU has memory, because the memory controller is on die, and the other processor had to go through the first CPU for access to memory anyway. In this case, I believe it's much faster, as the HyperTransport link on die is much faster.
Suppose one thread running on a CPU requires, say, 2 GB/s of memory throughput, the FSB provides 2 GB/s of memory throughput to each CPU "socket", and the memory controller can only provide a sustained 2 GB/s of memory throughput.
If the thread is running on a multi-CPU machine, CPU-A will get 2 GB/s to the memory controller, and the thread will saturate that link. In this case, multicore/multisocket won't matter: multicore might only have 2 GB/s to main memory, but main memory only can provide 2 GB/s anyway, so the extra 2 GB/s that the other socket gets is meaningless.... if you ignore commanding overhead. Including that, in this case, multicore will be slower than multisocket, because the extra bandwidth could raise the efficiency of the memory controller->memory link.
That's the only way I could think that POWER4 would be slower in multicore than multisocket: insufficient bus speed to main memory. If you've got sufficient overhead in the link to main memory (as the P4 and the Athlons do) then it absolutely will be faster than multisocket.
Unless the two cores on one die theory works aswell as a two cpu machine
It works better than a 2 CPU machine. Two cores are two CPUs (they couldn't be slower!), but they have the advantage of being able to have a much higher speed interconnect since it's implemented in silicon, not through logic and wiring.
Yah, but it was a pretty bad example for what you were trying to describe, because the signal propagation is far from instantaneous for anything.
Signals move at the speed of sound (or vibration) in a material, because you're not trying to move the material, you're trying to propagate a wave. It's not like pushing a stick - it's like dropping a rock in water. The water itself moves very slowly, but the wave propagates rapidly - at the speed of sound in water. Likewise, in a conductor, the electrons move slowly, but the signal propagates rapidly - at the speed of vibration of the electrons, which is the speed of light. Or 0.8c in a conductor.
Is the effect of gravity felt instantly, or does it travel at the speed of light too ?
Speed of light, according to general relativity. There were some experimental tests done involving a quasar eclipsing Jupiter or some such, but from what I had heard, they originally claimed to be consistent with the speed of light, but later it was shown that it didn't actually measure anything.
you could push and pull your end and communicate information to the guy at the other end faster than a radio signal moving at the speed of light
Work out the math. All the math - including the stresses involved.
You couldn't move the stick like that. Any physical stress on the stick would propagate at the speed of sound in the stick (much, much less than the speed of light).
Your normal experience of pushing and pulling sticks comes from the fact that distances involved are tiny.
If you tried to move the stick to propagate a signal faster than the speed of light, you would break the stick.
There is no way to transmit a signal faster than the speed of light right now. None.
Interestingly, the information in electrical signals is transferred by the electric field - which is transmitted by photons, which move at the speed of light. Which, in a conductor, is... 0.8c.
Being that, beating Tit for Tat isn't that big of a deal. Doing BETTER than Tit for Tat consistently _IS_ a big deal.
I think you missed some points of the research - the idea was to find "how many colluders do I need to beat Tit for Tat?"
Tit for Tat is quite possibly the best "single person" strategy. Against any other opponents not working together, Tit for Tat will typically win in a long enough iteration.
Now, we know that Tit for Tat isn't the best in cooperating environments - as someone else here pointed out, if you've got a Random opponent, a "use Tit for Tat, watch for Random, if Random, slam him to the wall." strategy will probably do better. That's akin to "cooperation", or at least "collusion" - said person will have more information.
The interesting point here is how many colluders you needed here - this showed it was about 20 or so. That's a large number. Given the total number of entrants, it says something about roughly how large an organization must be before it can score better than the ideal "logical person".
Given the fact that the systems that the PD applies to don't preclude collusion, this may have some interesting applications there. Certainly one can imagine applications in biology - cells, after all, do kill themselves to ensure the survival of the macroorganism. There might be some information here on the evolution of multicellular organisms.
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One IDE channel. No floppy, serial, parallel, or PS/2 ports. Kill IrDA support.
The problem is that virtually none of this saves money.
Legacy support costs virtually nothing. The only expensive parts are the connectors (the interfaces are all integrated: if you want IDE at *all*, you basically get everything else) and you can just put them on a pin header if you want.
IrDA, serial, and PS/2 are all the same thing - parallel, floppy, and even IDE are usually supported on one chip. They're so cheap that there's no point not to put them on. For one thing, they're useful enough to the people testing the board that they earn their keep just that way.
The CPU and RAM chips could be soldered onto the board. Bundle it with a cheap mass-market OEM hard drive, a case with a 40W power brick, and you've got a PC.
RAM prices fluctuate too much for this to be succesful. CPU integration makes sense, although again, the price drops quickly enough for you to be left with a platform that's far overpriced in just a few months. Keep in mind, that's one of the main reasons you don't integrate the CPU and memory - price concerns.
For one thing, in the time it takes the system to get to market, the board will be a bit overpriced/underpowered for its price point. Systems that have socketed CPUs/memory are viable on the market for a long enough period for people to sell off their supplies.
The way you make a cheap motherboard is to only use the integrated peripherals in the southbridge, and then volume, volume, volume.
Thankfully, the light truck (SUVs, basically) exemption was lifted in 2001: in 2005-2007, the minimum goes from 20.7 to 22.2. Not wonderful, but nice.
Blah, missed the fact that this only applies to vehicles under 8500 pounds. This includes *some* SUVs, but not all. Apparently the "over 8500" category is only ~10% of the total number, though. So many SUVs will be improving in fuel economy.
As for the US, you have the CAFE act. the point is that light trucks are exempt, so the car producers push for those. Ironically, they have grown popular even here, where this kind of loophole is neither existent nor necessary. BUT, over 70% of the Ford mondeos sold here are diesel cars.
Thankfully, the light truck (SUVs, basically) exemption was lifted in 2001: in 2005-2007, the minimum goes from 20.7 to 22.2. Not wonderful, but nice.
The funny thing is that people in the US treat government regulating mileage as if it's never happened before, completely forgetting CAFE and the rise from an average of 14 mpg to 28 mpg. The amazing thing to me is the fact that Congress hasn't pushed it up since 1990, especially nowadays with the price of gas going upwards, exactly as it did in 1974.
But, then again, the current administration in the US has no intention of lowering the US consumption of oil - just the price. Oh, it's not like they care about the price consumers pay - but the price that companies pay, now, that's different.
A small real life example: here in Italy,
See, I think this might be the reason for why I might appear so adamant - I was born, raised, and live in the US. Gas prices, in dollars per gallon in Italy, in February 2004, were $5.04. In the US they were $1.64. That's about 1/3 to 1/4.
Economics does in fact work (as I'm sure you know) - higher prices means less demand, and cars with better gas mileage are far more common in Europe. Heck, diesel is far more common in Europe than in the US, and even pushing for an increased diesel adoption in the US would be better, because diesel engines on average have 20% higher gas mileage than gasoline burning engines. Diesel adoption in the US should go up in the next few years, but given the spike in oil prices, I really would've expected federal laws to start being enacted to push diesel adoption faster. It's a great stopgap.
But the US is pushing the world faster towards mass chaos, and so for me, I look at my country's laws and trends, and I say "what the hell are you doing??" I look at other countries, like Europe, and I say "hey, if the US had the same policies the rest of the world did, we'd be fine." Really - the US is pushing for OPEC to accelerate oil production rates (in other words, pushing us *faster* towards the Hubbert peak) so they can have cheaper gas.
I mean, I drive a car from 1993. It gets 25 mpg city/35 mpg highway. This is advertised as very good gas mileage in the US nowadays on new cars! (In fact, if my car was sold today, it would be one the top 10 best gas mileage cars) This is insane - we've known how to build that kind of an engine for years. That's not 'good' gas mileage. It's average. In fact, it should be the minimum gas mileage sold for new cars nowadays.
The main problem I have with people dismissing global warming is the fact that CO2 emissions (hell, emitting anything into the atmosphere) isn't a long term strategy. Even if you don't think global warming is real, it's still smart to reduce CO2 emissions. Every other country in the world seems to recognize this except the US.
A large portion of the problem is the fact that in the US, we have politicians that can't seem to grasp the fact that just because someone says "oh, and this will help cut down on CO2 emissions, which aids global warming" doesn't mean that you can say "I don't agree with global warming, therefore I don't think what you're saying is reasonable."
If people don't believe that CO2 can cause global warming, they're idiots - and they've never gone inside a greenhouse. But seriously, I think that's what many politicians in the US think!
If you think "OK, I don't agree with this model", that's fine. That's logical, in fact. We can debate what the warming rate as a function of CO2 in the atmosphere is. Sure, no problem. But all that should do is mean that we're arguing about how fast we should be reducing CO2 emissions, not whether or not we should. And again, you look at the US - and it seems as if the current politicians do want to believe that we don't need to reduce CO2 emissions at all! There are very few policies in place to really start lifting the gas mileage of cars in the US - hence the reason that the average gas mileage of all vehicles in the US went *down* for about a decade. Down!
Sigh. So that's why I might seem so adamant - it seems like in other countries, if you say "well, I don't believe the global warming models" you're simply saying that we don't need to cut CO2 emissions amazingly fast. In the US, if you say the same thing, you're saying that we don't need to cut CO2 emissions at all. And that's just crazy.
If the term is long enough to cover several millenia, a plan for it, that begins with a few centuries of mere discussions, is a perfectly good one. Aggressive even...
OK, the whole "multi-millenia" thing was just to point out that even if you throw out running out of fossil fuels, and any possibility of global warming or environmental effects, you still have to cut down on CO2 emissions eventually, so, in the long run, it's still a good thing.
The end of fossil fuels and environmental effects are not multi-millenia effects. They'll show up in this century.
Besides, what do we need discussions for? The proper replacement for fossil fuels (and thus, cutting back on huge amounts of CO2 emissions) has been around for a while now. Replace most of the oil-burning/coal-burning/gas-burning power plants with combinations of nuclear, solar, wind, and hydroelectric plants. As a stopgap, introduce hybrid cars, and begin introducing a fuel cell based infrastructure, with hydrogen generation from either fossil fuels (temporarily) or electrolysis (in the long term).
Keeping the power plants, and continually building more oil-burning cars, only exacerbates the problem. Every dime you spend on those power plants to keep them alive for a longer period of time is foolish - they won't be profitable for an infinite period of time, so you shouldn't be planning on keeping them around for an infinite period of time. Likewise, the constant introduction of oil-burning cars is also foolish - those cars won't be affordable to drive over their lifespan. Most people, when looking at hybrid cars, for instance, look at the initial cost, and then say "well, I'd have to save $X each month to pay for it, and gas isn't that expensive." The problem is that they're neglecting the fact that gas prices, in the long term, must increase.
The other point regarding cars is the fact that it's extremely important to push hybrid cars into the market, because the new car sales are only a portion of the total car market - you need to get hybrid cars into the used market, rapidly. Tax credits for sale and purchase of hybrid cars would do this quite well. Plus, the increase in the number of hybrid cars would mean that more people are spending less money on gas, a portion of which goes overseas. So your trade deficit goes down, and from a government perspective, it's not only affordable, it's long-term beneficial.
The fact that certain people say that the cost is too high shows that they clearly don't understand the problem. The longer the fossil fuel plants and oil-burning cars operate, the more rapid the replacement plan must be, and the more expensive the plan must be. The sooner you start, the slower you can take the replacement plan. Simply require that power companies replace some fraction of their fossil-fuel burning plants with clean plants each year. Require that car manufacturers sell an increasing fraction of hybrid cars, and at some point start phasing in fuel-cell based cars.
The sooner it's done, the cheaper it is. And the less the consumer, and the companies will complain. In addition, the faster these companies switch off massive fossil fuel consumption, the longer the oil companies will be able to survive. It's just procrastination and short-term profiteering that's preventing it right now. It certainly isn't lack of sufficient motivation.
From this explanation. Twin A stays on Earth and Twin B sets off in a spaceship going 0.995 c (time and space will dilate to 1/10th). He reaches a point C that is 9.995 light-years away and heads back at the same speed. Let's assume accelleration is instantaneous. When Twin B leaves earth, both twins agree their clocks read zero. When Twin B reaches point C, Twin A sees that his clock reads 10 years and Twin B's clock reads 1 year. Twin B thinks his clock reads 1 year and Twin A's clock reads 0.1 year. As soon as he turns around, Twin A still thinks B's clock reads 1 year and his clock reads 10 years, but Twin B thinks his clock reads 1 year and Twin A's clock reads 19.9 years.
Sigh, all I ever hear are bad explanations of the Twin Paradox. Let's be clear - there's no need to invoke General Relativity to explain the Twin Paradox at all. It clears a few questions up, but you still don't need it.
Here is a great explanation using only Doppler shifts, which most people understand quite easily.
The problem that you have is that you're assuming that Twin A sees Twin B reach Point C at the same time that Twin B reaches point C - he doesn't!
From Twin A's frame, he sees Twin B leave at year 0. He calculates twin B arrive at point C at year 10, but he can't see twin B arrive at point C until the year 19.995, because any light signal from point C won't arrive at Twin A before then! Amazingly enough, in the 0.005 years before Twin B arrives home, all of the images of Twin B for his entire trip home arrive all in a bunch! They're all massively blueshifted!
So Twin A sees an outbound leg that took 19.995 years for all of the images to arrive, and an inbound leg that took 0.005 years to arrive. For Twin B, this isn't true - for the outbound trip, he sees Twin A age at 1/10 the speed, and when he arrives at Point C, he's only seen Twin A age 0.1 years. On the way back, however, Twin B will see Twin A age just as rapidly as Twin A sees Twin B age in the last 0.005 years - but he'll see it for an entire year! So Twin A ages far beyond Twin B, and they will both agree that Twin A is older.
There's a terrific spacetime diagram showing this here.
"Simultaneous" is meaningful in special relativity; it just depends on the reference frame.
I was clarifying, not disagreeing, with the simultaneous point. The definition he gave for simultaneous was basically correct well before special relativity, and didn't much change with special relativity. If you define your "dt" as being "the time from when the light emitted from when event 1 struck my eye to when the light from event 2 struck my eye", then even in classical mechanics, "simultaneous" depended on your reference frame. The difference was that previously there was always a presumption of the 'ether' frame, which was an absolute time reference, and relativity destroyed that.
So "simultaneous" really doesn't mean anything different in special relativity as it does in classical mechanics.
Proper distance, however, didn't exist before special relativity, and is very important in relativity. Two events with a timelike separation, for instance, can never be simultaneous in any frame. Two events with a spacelike separation, though, are always simultaneous in some frame.
The concept of "absolute time" really was what people thought of when they talked about "simultaneous", because they were talking about the absolute time separation between two events, and that concept really was shattered by special relativity, and that concept of "absolute time" (and "absolute spatial separation") was replaced by proper distance.
The part I (clearly) disagreed with was the part where he said that observers need to be tied to a frame for their observations to be useful. This isn't true, and it isn't the point of special relativity. The point is that things that we thought were invariants definitely weren't, but there are (new) constructions that were invariant. The "frame dependence" issue is far less important than the definition of the new frame-independent quantities, which led to quantum field theory.
..It seems to me that you are implicitly defining "reason" in contemporary terms.
Um. Yes?
Half the point of developing tools like the scientific method and analytical reasoning is so we can use them. As the methods become more refined, our trust in them should increase.
Thus, I should have more trust in scientists' results than a person in the year 1000 had in a fearmonger spouting off.
I would have liked any model to appropriately "explain" temp changes in the past: for example, average temps here in Italy have had significant swings in historical times when human activity, espacially CO2 related, can be assessed as varying between "negligible" to "nonexistent". As you see, no predictive content is required, only a "best fit".
Er... yes, of course, temperature variations have swung significantly in historical times. Temperature variations do happen over time - quite significantly. A large part of the warming over the past 1000 years is due to the eccentricity of the Earth's orbit decreasing (as it periodically does). We're definitely in a warming trend right now, just from natural causes.
But the CO2 levels are not from natural causes, and they're massively above what they've ever been in several hundred thousand years of data. See here to see what I mean: note the graphs showing the trends over time. Yes, we're in a natural warming period right now. But also note the scale of the CO2 graph - 175 to 300 parts per million, total variation.
Now look down at the graph at the bottom - that's the current trends on CO2 levels. Note the scale again - 280 to 340, and sharply rising currently. We're now about 10-15% above the highest levels of CO2 ever seen in the atmosphere, and it starts climbing almost exactly at the Industrial Revolution.
No one's trying to suggest they understand the atmosphere perfectly. Trying to explain the temperature rise, in my opinion, is also quite arrogant. But they certainly understand it enough to claim that a massive rise in CO2 will likely cause climactic effects, and they are certainly correct that we cannot simply continue pumping CO2 into the atmosphere at the present rate.
You are perfecly right in saying that CO2 is a earth warmer, and reducing that could impact; but what if it is later proven that it's all in the sunspots cycle, or other things?
Well, that's science - then the models were apparently wrong. But you're not asking what happens scientifically. You're asking how does that impact socially. And I'm presuming you mean to say "what if it is later proven that it's all in the sunspot cycle, and we reduced CO2 emissions for nothing?"
The answer to that is simple - no matter what, we have to reduce CO2 emissions eventually, because we can't keep burning oil/natural gas/coal forever . Since fossil fuels are the main cause of CO2 emission, reducing fossil fuel usage and reducing CO2 emission are the same thing. The cost will be the same (in inflation-adjusted dollars) at any point in time. We know how to do it now - we replace oil burning cars with hydrogen fuel cells, we replace oil/coal/natural gas power plants with nuclear/solar/wind. We can actually make it cheaper if we start now, and amortize the cost over 50 years, rather than doing it in 10 when the need is more obvious. As a bonus, the world will still have a large supply of cheap fossil fuels for many centuries to come after that. Fossil fuels, after all, have a good power density.
I'm not suggesting stopping fossil fuels now. I don't think anyone is. I think everyone is suggesting we start to stop using them, and by that, I mean regulations. I really find it insane that the US walked out on the Kyoto treaty. It's obvious to anyone that the world eventually has to stop emitting more CO2 than the world can handle. The only question is "how fast", and the US simply walked
If the atmosphere were a great scatterer of visible light, that's exactly what you'd get.
No, if the atmosphere were a great wavelength-independent scatterer of visible light, that's what you'd get. As it turns out, the sky is not blue because the sky scatters blue light most effectively - the sky is blue because the Sun is blue. Blue-green, to be specific.
If the Sun was a uniform source of light, the sky would be purple, because the sky scatters purple light most effectively. If the sky scattered light tremendously, it would look white, but that's simply because our eyes have saturation limits. If you did spectroscopy on the sky, it would still be purple.
Rayleigh scattering is strongly dependent upon wavelength. That's why the sky looks blue.
And as for that odd white fog you talk about, there seems to be a ton of it covering me right now. They call them clouds - and they cover 60% of the Earth's surface on average. Which is also another reason why changing the surface albedo doesn't necessarily change the temperature of the planet in the simple way that you might think.
We currently are raising CO2 levels in the atmosphere by 2 parts per million per year.
We eventually have to be raising CO2 levels in the atmosphere by 0 parts per million per year.
That was the entire point of the statement regarding suffocation. Many people say "we shouldn't cut back on CO2 emissions - it's too costly." My point is that fundamentally, we have to.
Aha, now we are switching the subject slightly from CO2 emissions to oil shortage.
No - I included oil burning because oil burning is a major source of CO2 emissions. Cutting down on oil burning (without replacing it with a new form of CO2 emission) is cutting back on CO2 emission.
And note that I never talked about an oil shortage. I said the peak oil production.
An awful lot will change -- we may have cold fusion and interstellar travel by then.
Basing policy decisions on the possibility of future breakthroughs is not a solid long-term plan. It is far more efficient, and prudent, to begin the change gradually, and then, if the change is later deemed unnecessary, roll back the changes.
we were supposed to run out of the stuff already.
I'm not talking about running out of oil. I'm talking about oil production peaking. And when oil production peaks, the price will not go uniformly up, because demand is linked with price (also known as a feedback loop). Instead, the price will fluctuate wildly. Read here for more. Don't suggest that people have been predicting the end of oil reserves for years. They haven't. Hubbert predicted the US oil production would peak in the 1970s. It did. That led to a very volatile period in gas prices in the US.
start we start sacrificing now for the sake of our future great-great-....-grandchildren thousands of years from now are not at all convincing.
Managing current resources for future needs is the responsibility of any government. It is, in fact, one of the chief reasons we have governments. There is a phrase for people who ignore long-term problems for short-term gains: we call them "short-sighted." It's generally considered derogatory.
Because they hope, it may get them elected.
It might also have something to do with the fact that oil concerns are driving foreign policy. The US is dependent upon foreign oil. This is a liability, just as any 'debt' is a liability. Both candidates (and, I imagine, a huge majority of citizens, economists, and scientists) insist that it is a good idea to eliminate dependency on foreign oil.
So, if we A: need to cut back on oil consumption very soon, B: have reason to believe that CO2 emission (mainly from oil) also needs to be cut back, why don't we do both if the cost is only marginally higher than doing one alone (which it is)?
Because both require very expensive solutions to something, that is not even problem. At least, not yet -- unlike, say, cancer, terrorism, AIDS, budget deficit, malaria, and obesity.
1: There will always be current problems right in our face that seem more immediate. That does not mean that a long term problem cannot be more severe and require just as much attention.
2: They both require the same solution! It's efficient to tackle both problems at once, rather than develop something that fixes one problem and leaves the other. You'll end up spending more money in the long term.
Change always is expensive. That doesn't mean that it isn't profitable in the long term. Given the huge amount of money that's flowing out of the US for foreign oil, I can't imagine that any cost/benefit analysis for any reasonably long period of time for the US would suggest continually burning oil. It's a losing position.
And it's interesting that you mentioned the budget deficit, as it's also linked to these problems, because we have such a huge amount of money flowing overseas to buy oil. If we cut back on burning oil, in favor of locally generated power sources, then that money stays here, and the trade deficit goes down. And then the budget deficit goes down as well.
In relativity, "simultaneous" means an event occurs at the same time in the same reference frame.
Actually, no. In relativity, "simultaneous" doesn't mean anything. That's half the point.
Before relativity, we had several ways of describing causality - we could say that "event A happened before event B", "event A happened at the same time as event B", "event A happened after event B" - and those definitions seemed absolute, just like the distances between objects were absolute - the distance between point X and point Y was D.
But relativity changed that.
That's because the notion of the "temporal distance" between two objects (that is, "dt^2") isn't invariant between reference frames. Neither is the spatial distance (that is, "dr^2 = dx^2 + dy^2 + dz^2").
any observer must be assigned to a frame for his observations to be useful.
That's the part that's a little wrong - see, there are several invariants - things that are the same in all reference frames - in relativity. Specifically, the proper distance, or "ds^2 = (cdt)^2 - dx^2 - dy^2 - dz^2". In *every* reference frame, that quantity will be exactly the same. So you can speak of quantities without reference frames. I can say that the proper distance between the point and time at which a photon from a lightbulb was emitted to the point and time that my eye registered it is zero - and every observer would agree with me.
So while before we could say "before, simultaneous, after", we now can say "spacelike, lightlike, timelike" - if the proper distance is less than 0, equal to 0, or greater than 0. In *any* frame, those measurements will stay the same.
It's important to recognize that relativity doesn't say that *all* measurements are subjective. Of course it doesn't say that - the speed of light, for instance, is the same in all frames. What it does say is that a lot of the quantities we used to measure are subjective - specifically, spatial and temporal displacement, momentum, and even things like electric and magnetic fields. Those are relative - but there are quantities underlying them which are invariant.
Why mandate anything now, when both the technology is still expensive, and the need is far from obvious? By your estimates, we can safely wait another 3-7 thousand years, and if our kin does not have the right technology by that time, than may be they deserve to die out.
It's utterly amazing that you read everything that I wrote, and missed the point entirely.
We can't wait 3 to 7 thousand years. I never said that. I simply said that it's insane to even consider that we can continue pumping out CO2 indefinitely. We can't. No one could possibly suggest that we could. 10,000 years is still less than infinity. That's all that I meant.
Since we have to stop sometime, that means we have to begin stopping at some point as well. If we don't do it soon, we're just putting it off, and we're going to make the rate at which we have to cut down on emissions much, much higher.
A simple cost-benefit analysis suggests, the resources can be spent on something much more useful.
No, it doesn't. We're clearly approaching the peak of oil production in less than 100 years. We can either continue the way we are now and change very violently in fifty-sixty years, or change gradually now and not wreck the world's economy.
Why do you think people are talking about "reducing our dependency on foreign oil"? Why don't we tackle both problems at once and reduce CO2 emissions as well? Why risk it?
I think one way to inoculate oneself against this disease is to become aware of the trigger words and phrases, which seem to act as vectors for the disease. Words and phrases such as Liberal, Tax Cut, Tax Cut for the Rich, Terrorism, Spreading Liberty and Freedom thru the World and many others are used to turn of your capacity for analysis. But we can reprogram ourselves to respond to such triggers with increased skepticism and increased vigilance.
Actually, I've decided that if anyone comes to my door and tries to spew rhetoric that's demonstrably wrong, and clearly doesn't know what they're stating (say, someone saying that Kerry is the "first-most liberal senator in Congress", for instance, and then not knowing over what time period that was considered to happen) I'm going to get my jacket, follow them around with my laptop and wireless internet connection, stand behind them when they go to people's doors, and show the people the truth.
I actually don't mind if people spew rhetoric that's spun slightly that they know the truth behind. There are many ways to present data, for instance - I don't begrudge Bush for saying that he increased the number of Pell grants - he did - but then Kerry is perfectly fair to point out that he cut the total amount of money, as well. Some people might think that it's more important that more students get money, even if it is less - not me, of course. I've gotten Pell grants. I know how important that money was.
It's like 'whisper down the line' - if you know the beginning of the whisper, you will only distort the whisper so much. If you don't, though, then you can end up incredibly far off from the truth.
Um, then the predictions are wrong, and we'll find out. That's science!
Now, if you're trying to use this to justify policy, that's a different point. After all:
If you approach the problem logically, we're fools not to start cutting down on CO2 usage now and start phasing in newer, cleaner technologies (mandating hybrid cars, pushing towards non-fossil fuel power plants, etc.).
We have to do it eventually. There are little downsides to doing it too early, and in fact, several possible positives. There are many possible severe downsides to doing it too late.
Essentially, Earth's societies are procrastinating. We have to do it eventually. We just don't want to start doing it yet. This is naive, and quite dangerous.
The problem with some people who worry about global warming is that they have a tendency to say that severely reducing carbon dioxide emissions is the only way to prevent disaster- and while that's a lovely sentiment, it is excessively impractical.
Fundamentally, humans must cut back severely on carbon dioxide emissions eventually. We're obviously pumping more CO2 into the atmosphere than plants can handle (hence the reason that the CO2 level is going up at all). If we continue at the current rate of emissions, then eventually, the atmosphere will be primarily CO2. Currently it's +1-2ppm/year. In 100,000 years, CO2 would be 10-20% of the Earth's atmosphere, and we would all die.
And this is assuming that the rate of CO2 emissions doesn't increase. It, of course, currently is increasing.
Obviously this won't happen - fossil fuels are the primary culprit, and we don't have enough of them to continue for 100,000 years.
But that just reinforces the point - we have to severely reduce CO2 emissions eventually - either by choice or not. So why not start now? For one thing, it would ensure that fossil fuels (with their conveniently high stored energy density) would be usable for more irreplaceable needs.
Or we could just continue blindly burning fossil fuels until we hit the peak oil consumption, and watch the entire world's economy go haywire.
"The end is near! repent ye sinners!", and remember: they were in good faith.
No, it wasn't in good faith. They had no reasonable belief to assert such a statement. If they said that, it was self-serving fearmongering (or paranoia).
unless these climatologists present a viable climate model by which changes in human activity determine the climate, they have the same credibility, I'm afraid.
What's a "viable climate model"? One which explains all changes to the climate and predicts all weather perfectly? That's never going to happen - ever. And it's not needed, either.
For the same reason that biology can't produce a viable model based on fundamental theory for the way that organisms act, meteorology can't do it either. Biology can (and do) formulate hypotheses and theories based upon phenomenology, and use those to predict. They are more correct than they are wrong.
In exactly the same way, climatologists can use formulate hypotheses and theories based upon empirical data - that is, historical data about the climate record - and use it to predict current data.
Saying that they have to have a perfect climate model is ludicrous. And comparing them to fearmongers is also ludicrous.
This is simple, freshman physics we're talking about here.
There's also no doubt they're right that CO2 warms the atmosphere, as well. If you triple the amount of CO2 in the atmosphere, it's going to warm up. We also know this from observations of other planets' atmospheres. Anyone who runs a greenhouse knows this. We've now increased the CO2 level by 25% - higher than ever seen in ice core data. Our CO2 output is still increasing, which means that CO2 levels in the atmosphere are still increasing. At some point, the increased CO2 will increase the global temperature. It's not a question of "if". It's a question of "when".
No reasonable scientist could possibly believe that we can continue dumping CO2 into the atmosphere indefinitely. So it's obvious that at some point we *do* have to curtail atmospheric CO2 emissions. Why put it off?
CO2 is transparent to visible light. CO2 cannot prevent the reflection of visible light at the surface back out into space.
You're presuming that visible light incident upon the surface of the Earth produces the Earth's global temperature.
This is demonstrably wrong. In fact, you can relatively easily calculate the Earth's temperature if this were true. It's called the blackbody temperature: here is a description.
Earth's atmosphere is in fact specifically responsible for absorbing a large portion of the reflected light (it scatters visible light quite effectively - hence the reason that the sky is blue. some of that scattered energy goes into the atmosphere as heat). If it wasn't, Earth's temperature would be below freezing. Changing the overall albedo of the Earth may or may not have the intended effect. It's in fact quite complicated, as the atmospheric scattering depends quite strongly on wavelength.
Then the other problem is that if we do do this, and it does work, we've essentially increased the temperature dependence of the atmosphere on the solar input, which means that the time dependence of temperature would go up dramatically.
He has been mean to guests, but it's only when they come on and try to treat it as a news show - that is, by giving meaningless talking points.
Best one was when a guy came on and said "well, Kerry's the first most liberal senator" at which point Stewart popped up and said "who said that?" and the response was "Well, they come up with this compilation of votes..." and he responded "Who is 'they'?"
He did this over, and over. That is what Stewart hates, and I agree with him. He hates talking points. Today's media is 20 seconds of fame, not 20 minutes of fame. You say one phrase, and it sticks with you - take Bush constantly quoting Kerry's "global test" regardless of the fact that he never used it in the way he meant it. (He said our actions must pass a global test, not that our decisions must be decided by a global test. This is akin to saying "I would like to beat you to a bloody pulp, but that would probably make society throw me in jail.") or Kerry constantly using figures that are bloated out of context for effect.
God, do I agree with Stewart. I can't watch the news anymore. They're not journalists. They're microphones for politicians, and that's all. It's why I watch the Daily Show. Now I know, for instance, what that "first most liberal senator" thing means. And I know that the Republicans will beat people over the head with it, and I know that they don't even know what they're quoting! The same is true for Democrats, as well (God, I've heard enough Democrat rhetoric to make me sick).
What's interesting is that most Republicans tend to avoid talking for 'real' on the Daily Show, and so they get beaten up a little. Democrats seem to understand that Stewart won't let them pull the 'talking points' thing. Certain Republicans understand - McCain, for instance, or the head of the RNC who was on.
In practice a multi-core is slower than separate, because they have to share the same bus to main memory. Well, at least in my experience with the POWER4, that is.
... if you ignore commanding overhead. Including that, in this case, multicore will be slower than multisocket, because the extra bandwidth could raise the efficiency of the memory controller->memory link.
I'm only tangentially familiar with POWER4, but it seems like the bus speed isn't high enough. So long as the bus speed exceeds the bandwidth of the memory controller by a significant margin (and the chips didn't have onboard memory controllers + their own memory like the A64), I don't see how, in practice, it could matter.
For a Pentium 4, for instance, it will be faster, because *all* multiprocessor architectures are shared-bus topologies, so it doesn't matter if there is one set of wires that multiplex inside the chip, or two sets of wires that multiplex outside the chip. It's still a shared bus.
For an Athlon 64, it's faster than a multiprocessor solution in which only one CPU has memory, because the memory controller is on die, and the other processor had to go through the first CPU for access to memory anyway. In this case, I believe it's much faster, as the HyperTransport link on die is much faster.
Suppose one thread running on a CPU requires, say, 2 GB/s of memory throughput, the FSB provides 2 GB/s of memory throughput to each CPU "socket", and the memory controller can only provide a sustained 2 GB/s of memory throughput.
If the thread is running on a multi-CPU machine, CPU-A will get 2 GB/s to the memory controller, and the thread will saturate that link. In this case, multicore/multisocket won't matter: multicore might only have 2 GB/s to main memory, but main memory only can provide 2 GB/s anyway, so the extra 2 GB/s that the other socket gets is meaningless.
That's the only way I could think that POWER4 would be slower in multicore than multisocket: insufficient bus speed to main memory. If you've got sufficient overhead in the link to main memory (as the P4 and the Athlons do) then it absolutely will be faster than multisocket.
Unless the two cores on one die theory works aswell as a two cpu machine
It works better than a 2 CPU machine. Two cores are two CPUs (they couldn't be slower!), but they have the advantage of being able to have a much higher speed interconnect since it's implemented in silicon, not through logic and wiring.
Yah, but it was a pretty bad example for what you were trying to describe, because the signal propagation is far from instantaneous for anything.
Signals move at the speed of sound (or vibration) in a material, because you're not trying to move the material, you're trying to propagate a wave. It's not like pushing a stick - it's like dropping a rock in water. The water itself moves very slowly, but the wave propagates rapidly - at the speed of sound in water. Likewise, in a conductor, the electrons move slowly, but the signal propagates rapidly - at the speed of vibration of the electrons, which is the speed of light. Or 0.8c in a conductor.
Is the effect of gravity felt instantly, or does it travel at the speed of light too ?
Speed of light, according to general relativity. There were some experimental tests done involving a quasar eclipsing Jupiter or some such, but from what I had heard, they originally claimed to be consistent with the speed of light, but later it was shown that it didn't actually measure anything.
you could push and pull your end and communicate information to the guy at the other end faster than a radio signal moving at the speed of light
Work out the math. All the math - including the stresses involved.
You couldn't move the stick like that. Any physical stress on the stick would propagate at the speed of sound in the stick (much, much less than the speed of light).
Your normal experience of pushing and pulling sticks comes from the fact that distances involved are tiny.
If you tried to move the stick to propagate a signal faster than the speed of light, you would break the stick.
There is no way to transmit a signal faster than the speed of light right now. None.
Interestingly, the information in electrical signals is transferred by the electric field - which is transmitted by photons, which move at the speed of light. Which, in a conductor, is... 0.8c.
That story would be
/.ers don't read the article, eh?
here, rather than the Cassini/Huygens probe story that was linked to.
More proof that
Being that, beating Tit for Tat isn't that big of a deal. Doing BETTER than Tit for Tat consistently _IS_ a big deal.
I think you missed some points of the research - the idea was to find "how many colluders do I need to beat Tit for Tat?"
Tit for Tat is quite possibly the best "single person" strategy. Against any other opponents not working together, Tit for Tat will typically win in a long enough iteration.
Now, we know that Tit for Tat isn't the best in cooperating environments - as someone else here pointed out, if you've got a Random opponent, a "use Tit for Tat, watch for Random, if Random, slam him to the wall." strategy will probably do better. That's akin to "cooperation", or at least "collusion" - said person will have more information.
The interesting point here is how many colluders you needed here - this showed it was about 20 or so. That's a large number. Given the total number of entrants, it says something about roughly how large an organization must be before it can score better than the ideal "logical person".
Given the fact that the systems that the PD applies to don't preclude collusion, this may have some interesting applications there. Certainly one can imagine applications in biology - cells, after all, do kill themselves to ensure the survival of the macroorganism. There might be some information here on the evolution of multicellular organisms.