Nah. Doesn't work. You have to be approximately 1 wavelength away for that to work, in this case we would be millions of wavelengths.
and once the "Rocket" is high enough, why not use more than one transmitter... have the transmitters arranged in consecutive circles.
Provided the rings are within a wavelength of each other; yup. Otherwise, nope; you get a horrible diffraction grating effect and most of the power slops around and probably takes out bystanders.
Let's see if I have this right.. you broadcast your packets on a public network where you already assume anyone can potentially get access to them, then you worry about what happens when the government steps in and asks to receive a copy of those packets?
Just because they can do it, or even if they do it, doesn't mean that it is necessary lawful for them to do it. It may be considered a form of wiretapping, but it would be for the court to decide; I'm not aware of any case law on this.
Like what, the government isn't already part of "anybody"?
We elect "somebody", not "anybody"; if they start acting like they're anybody, then they're history in the long term in any true democracy.
You know, if that fuel is 98% hydrogen peroxide (HTP), then it might even work. Carmack tried to buy some from FMC, $100,000 worth would you believe. They turned him down... He has no source of HTP right now, and he's just run out. Bummer.
Edward De Bono ran a course for developing critical thinking. He also came up with a hat system; the idea is you put on a particular sort of hat and try to think in a particular way- today, I'm wearing my creative hat, or a what can go wrong hat or whatever.
You could try running one of those courses I guess.
I knew this was a large subject, when I started it, but wanted present the concept of the exponential rocket equation. I'm working on a full write up on my site and should have something up by the next slashback.
I don't think I'm going to hold my breath on this. You don't appear to know the difference between energy and fuel, and waving your hand like:
Let's not let excessive details (which apply similarly to both vehicles) obfuscate the elegant simplicity of the rocket equation.
Really doesn't cut it when conventional rockets leave the atmosphere as soon as possible to avoid drag, whereas airbreathing vehicles necessarily sit right in the draggy atmosphere the whole time they are thrusting.
The other factor you've forgotten is thrust:weight ratios. Conventional rocket engines have 100:1 thrust:weight ratios, airbreathing rockets are lucky to get 10:1. That means that the dry weight of the vehicle is 10x higher. That greatly offsets any reduction in fuel use- and LOX/Kerosene fuel is dirt cheap (under $1/kg), whereas the airbreathing mass is typically very expensive. So you've typically swapped cheap fuel for expensive hardware, not good.
The big problem with microwaves is focusing them down. For this to work you need most of the microwave energy you are pointing at the vehicle to make it to the vehicle.
Normally when microwaves are used for sending signals, for example satellite TV or point-point transmission, most of the power ends up missing the receiver, but the receiver amplifies the signal using power from the mains.
When you have a rocket, there's obviously no power cord;-), so you need the vehicle to catch as much of the microwaves as possible.
However, there's a law of nature that says that the maximum focusing you can do is determined by the size of the transmitter antenna and the wavelength of the microwaves you are sending.
So:
angle of transmitted beam (in radians)
= 1.22 * wavelength/diameter of antenna
wavelength of 100Ghz microwaves = 300,000,000/100,000,000,000 = 3mm (1/8 of an inch)
Let's make the diameter of transmitter = 10 m (say). (This is a huge transmitter, ~30 feet diameter, reasonably big).
This gives the angle of the beam to be: 1.22 * 0.003/10 = 0.000366 radians
At 200km, this means that the beam is: 200,000 * 0.000366 = 73m wide (~200 feet)
That means that your rocket would have to be 200 feet in diameter to capture most of this energy. Which is very likely to be heavy.
The only way to improve on that is to go to a higher frequency, difficult from 100 Ghz, or make the transmitter bigger, 100 meters (~300 yards?) and bring the rocket down to 7.3m (21 yards) diameter, but it's still all a bit awkward. Oh yeah, and you can't use 'synthetic aperture techniques'- you can't have a few widely spaced transmitters 100m apart, it turns out that doesn't work, you get huge sidebeams that suck away your power and it never reaches the vehicle, and those sidebeams are hazardous.
Still, it might be good for climbing up some way through the atmosphere, and then using a conventional rocket the rest of the way.
Feel free to play with the numbers, I'm not saying it absolutely doesn't work, it certainly works at low altitudes, I'm just trying to demonstrate the difficulties with microwave beamed power in this context.
Yes, but even having 10x more fuel still only costs 1% of the cost of the rocket. So you need bigger engines to carry the fuel up- but the thrust:weight ratio of rocket engines are typically 100:1, so one hundred tonnes of fuel is carried by 1 tonne of engines.
And because the dry mass of the rocket is the expensive bit, you haven't pushed up the cost of the vehicle by much.
And air is actually a much worse propellent than rocket fuel; you need many times more energy than the better rocket fuels to get the same thrust. That and the fact that airbreathing vehicles make you stay in the atmosphere for longer means you get much more drag- and drag goes up with the square of your velocity- mach 25 is needed for orbit, and people complain about Concorde being inefficient at mach 2!
Apart from being radioactive, it's a heap of junk;-) (Sorry!)
The problem is that because it is such a heavy atom when you heat it, it ends up moving very slowly. By conservation of momentum, your rocket ends up moving much more slowly than if you had used hydrogen, or even nitrogen for the same mass of fuel (the fuel would be much denser, but still, it turns out to be a big, big loss).
Your statement that a reduction in fuel by a factor of ten is not possible is very wrong.
What statement? I said your calculation that you would only need 10% of the energy was bogus; and I stand by that. In externally powered airbreathing rockets as we are discussing here, the energy and the fuel are unrelated; or are only related by the trajectory you've chosen to use.
For a given orbit, provided exhaust velocities are equal, a rocket which does not carry its fuel will always use less fuel.
Trivially true. However, with an airbreathing rocket the last point on its orbit where it burns atmosphere is necessarily within the atmosphere and hence it's orbit will still intersect the atmosphere, and you can't achieve a stable orbit; so you need to carry some fuel with you (there are a few sneaky ways around that, for example doing a slingshot around the moon, but they are often at best rather awkward). Additionally, the whole time you are in the atmosphere you are fighting drag; you absolutely cannot ignore that effect.
A better way for you to argue against a power savings is to point out that there's no way super heated air could ever achieve the exhaust velocity equal to that of kerosine and liquid oxygen.
No, not really. Superheated air can go faster than kerosene and LOX, if you heat it enough. But the molecular mass of nitrogen (air is mostly nitrogen) is pretty high. The exhaust velocity that can be achieved for a particular energy is inversely related with molecular mass, so air is fairly poor in that regard; by way of contrast kerosene has lots of hydrogen in it, and so requires less energy for a given exhaust velocity.
Energy or fuel mass isn't really the problem anyway. More important is the dry mass of your rocket, since that's the bit that costs the most (it turns out surprisingly that fuel is much cheaper than the cost of the vehicle, fuel is less than 1% of the total cost, fabrication of the metal bits and so forth are much more expensive).
The energy required is simply the orbital energy, given by half the gravitational potential energy (derivation mercifully omitted) of the payload, given by E = -(G m0 M)/2r.
That's not actually true at all. For a few reasons:
a) some (a lot) of the energy ends up in moving the exhaust around (for example you have to throw it downwards to get thrust from it- unlike the case where you carry the fuel with you the propellent has to end up moving downwards, since it was stationary when you met it).
b) gravity losses- until you reach orbit you're falling all the time; it costs energy keeping you up until then.
c) aerodynamic drag getting there (a lot, since you need be in the atmosphere to collect your fuel, and you're trying to achieve orbital velocity -mach 25 or so there; normal rockets get out of the atmosphere sharpish to minimise that problem)
d) no air at orbital altitudes; so you need some on-board fuel to circularise your orbit at the very least.
Also, many remotely powered vehicles have high exhaust velocities. That means that the amount of power left in the exhaust is many times greater than in the vehicle (energy efficiency is inversely proportional to exhaust velocity, roughly).
Frankly, I don't see any easy way to work out how energy efficient a system like that would be; it's trajectory specific. It may be more efficient, but certainly not an order of magnitude; and it's quite possible that it's less efficient particularly if the exhaust velocity is very high.
I just hope they've done this more than 20 times, and the network mafia go around and remove an appendage for each time they'd set up someone with a bogus IP address like that.
Still, I suppose if it is being NAT'd properly, it maybe ok, I guess [pained look].
>but as a way of losing weight; it's pretty sucky.
That's all a matter of perspective. Some people would much rather build up to a two-hour, vigorous workout than give up beer and pizza.
Yeah, well those people are likely to stay fat; unless they eat those things in moderation, the effect of exercise in the short term is fairly minor, and the effect of eating too much is quite large. The long term is different- in the long term exercise can help keep the weight off, if you keep at it and has other benefits.
Religiously insisting on meals being "balanced" could easily mean that in order to give your body what it needs you are also throwing a lot of stuff it dosn't need at it.
Huh? What are you supposed to be balancing it against except your bodies needs? Sure, you don't need to balance every meal. Every day is more like it; the point is to avoid actual deficiencies, because then you will tend to be hungry; or it will affect your health.
First of all, running, walking, swimming, etc. "only" burns calories at about the rate you suggest, but it also raises your metabolism so you are burning more calories the rest of the day, after the workout is over.
Yeah. It helps a bit. But it's still difficult to lose significant weight by exercise.
Secondly, a pound a week is pretty close the fastest rate anybody should lose weight. If you are losing weight much faster than that, all you are mostly dehydrating and/or losing muscle mass, not getting slimmer.
I'm saying losing a pound a week by exercise alone is completely out of the question for 90+% of the population. What you say about losing mass is incorrect; if you are dieting- you are losing muscle mass; it's just a question of proportion. If you diet too fast you will lose 50:50 muscle/fat. If you diet more slowly with a bit of exercise more like 20:80. It's important to do some, but don't ever think that you can lose much weight that way.
Thirdly, it is almost impossible to get proper nutrients if you are only eating 500 calories a day.
Gee. Do you think?;-) Hey, here's an idea, why don't you read what I wrote? I said cut back BY 500 calories, not TO 500 calories.
You most certainly can lose weight by exercise alone, so long as you're regular food intake is not excessive.
Sure, but it's very slow; far, far under a pound a week unless you are incredibly fit. It may help you keep your weight stable once you get there, and it does tend to maintain muscle mass; but as a way of losing weight; it's pretty sucky.
I don't buy this complex carb theory. It's not how complex the carb is, it's how quickly it is absorbed, and how good for you the food is. Maltodextrin is a complex carb, but is absorbed the most quickly of any carbohydrate.
Check out the Glycemic Index (GI). If you eat mainly low GI foods, you will generally be less hungry, and your body will have more time to deal with the carbs without turning them into fat.
Eating some fruit every day is great. However if you eat a lot of fruit every day, then it's probably bad for you (e.g. a dozen tangerines).
However, fat is far worse than anything. Avoid fats, they have no nutritional value. Therfore, you should not eat loads of bacon everyday. Eggs, the whites are good for you, the yolks are full of calories and fats. Again, avoid fats.
Nope. Fats are essential for life. A whole egg per day is GOOD for you. (Some early research said otherwise, however it turned out they were using dried eggs, fresh eggs turn out to be ok, and contain vitamins). However you should definitely minimise saturated and hydrogenated fats. Unsaturated should be eaten in moderation, and monounsaturated- eat lots of that.
Meats --- lean meats can provide a great source of long-term energy.
Yeah lean meat is good; fish (particularly oily fish) is as good or better.
The other subtle trick is to eat a really, really balanced diet. That means:
- enough protein
- some fat (olive oil, almonds, oily fish, pine nut kernels)
- not too many carbs (enough for whatever exercise you are doing)
- plenty, plenty of vegetables (cooked till water changes colour is much better than uncooked)
- some fruit
The point is that when people are hungry; sometimes they really are lacking in something. If you aren't eating a balanced diet you will tend to feel hungry because your body needs something. And that is more likely when you are on a diet.
Nope. It's reducing food calories. You have to run/jog for an hour to burn 600 calories or so. That's 1/5 of a pound. If you run for an hour per day, every weekday you might lose a pound a week. But most people are likely to be exhausted; if they can even physically do it.
On the other hand, if you cut back 500 calories a day then you will lose a pound a week. That's much less than 1/4 of most peoples food.
You're wisest to combine the two, exercise and dieting. But of the two, reducing food intake is absolutely critical, exercise merely helps. You basically can't lose weight solely by exercise; well not unless you are incredibly fit to start with, which most people certainly aren't.
My lifting consists of 1-2 hours typically (depending on how focused I am), and I have a 6 day split (2 days on, 1 day off, all 6 to cover my whole body). I aim for at least 30 minutes of cardio per day, sometimes I do more sometimes I do less...
That's a shitload of exercise (technical term). Probably 95% of the population simply can't do that much exercise. You're probably genetically lucky; and/or you have been training for a very long time.
Aim for 1.5-2g of protein per pound of lean bodyweight.
You don't need to eat that much protein. The studies suggest that about 1.5g per kg of bodyweight is plenty; and once you have trained you need less, since your body recycles the protein. (Proteins get damaged during exercise, but it gets recycled, and as you train, your body gets better at doing that.)
Your goal (for men) should be to drop your body fat percentage to well under 10% (under 15% for women).
Yeah, well you could do that. But most women have difficulty going below 30%.
Many Histories says we got here by many prior paths that coallesced. That much is essentially certain. Many Worlds says that here isn't the only point- there are many other parallel universes out there too that we can't reach.
Most top physicists agree with Many Histories; it's more or less a consensus position. Many Worlds is a bit more controversial.
I would take Davies's article with a large dose of salt.
There is actually evidence FOR multiverses.
Consider the twin slit experiment. You shine single photons through the slits, and they arrive in a single photon in a well defined location.
And yet there are places where it never arrives. These places suggest that single photon has somehow travelled through BOTH slits and destructively interfered on arrival. Essentially all generally accepted interpretations of QM say that this is what happened in fact.
The simplest theory for this is the 'many histories' theory where the universe has effectively split into two and then recombined to give one universe again; and triggered the interference patterns whilst doing it. (The many worlds theory expresses this in terms of wavefunction rather than universes but the effect is the same).
Trouble is; if it could split twice, why couldn't it split 3 times or 4 or a million times? Perhaps it did- perhaps we only see the universe which precedes our own, the others are elsewhere diverging slowly away...
And there's another problem; how do you explain what happened to the universes we never saw? They certainly should have happened, and to the extent that we can see them, we do see them; so assuming that they don't exist probably requires an act of faith.
Lets invent a term: "special" languages used for the purpose of "declaring" behaviour could be called..."declarative languages".
Yes, it would be a declarative language. No, it would not be necessarily like, say, Prolog; although you might be able to implement it in a language like Prolog.
The easiest way to make it parallisable would be to only allow expressions with no side effects, so passive function application would have to be the primary means of computation.
You could certainly express the specification in a functional language. But it's unnecessary, exploring program space is highly parallelisable without much communication so it doesn't get you far.
The point is not to write a program in a declarative language. The point is to write a specification in a declarative language that describes the behaviour of a program to quickly solve a class of problems. If you want to look at this as a prolog compiler on steroids, then I think you're not entirely wrong, but you've missed the spirit of the idea.
Just because something is equivalent to a compiled Prolog program doesn't mean that's the best way to implement it; on the other hand it doesn't mean it isn't either. (Actually, since Prolog is Turing complete, everything is equivalent to a compiled Prolog program, that's partly why I think you've got the wrong end of the stick.)
If the computer generates the runtime code automatically (I don't necessarily agree with using GAs in fact, it seems there's lots of search algorithms out there that usually outperform GAs, but GAs do seem to work); then the question becomes one of testing it. Therefore, the programming becomes not, writing the code, but specifying what code has to do in some way, and then the computer writes the code to match.
So say you want a chess program. You feed in the rules of the game in a special language, and it generates a program to play by searching for the program that successfully implements that.
That sounds fantastic! You'll never have to write another line of code ever again!
Hold on, don't get excited, it's not that simple.
First, just because it plays a game of chess, doesn't mean it plays a good game of chess, so you might still have to tell it in quite high detail what 'good' means in terms of your program specification.
Secondly, it's very easy to tell it the specification incorrectly. Specification errors are very common in computer software already, and having the highly precise specification language that you'll need doesn't make it easier, although the machine is less likely to screw up the implementation, so you're still better off than coding by hand.
Still, in some cases, where the problem is easy to state, you should have a solution program in just a few minutes; whereas now it could take hours or days.
Anyway that's where I see it go. There are some existing implementations of this kind of thing out there already, but they tend to be small. For example somebody wrote a program to find the shortest program to perform certain operations for gcc backends. You pretty much just point the compiler at a new processor and optimum code pops out, it's kind of neat. But currently this is limited to maybe 15 instructions long. I think that this will grow enormously, particularly if you throw away the constraint of having to be completely optimal, and allow 'only slightly suboptimal' programs; and faster and faster processors are coming down the pipe; so 'searching for code' is becoming more practical.
Oh yeah, and the idea probably works for parallel and quantum computers too. Parallel searching for optimum parallel code, and so forth.
And I suppose the whole tires flying apart, ripping away wing surface/ exploding out of the sky thing had nothing to do with it?
Nothing at all, really, except in the most trivial sense of triggering it's final demise. The big, huge problem was that the aircraft never sold. Otherwise they might still be building them. And it never sold due to exagerated environmental concerns.
As exaggerated environmental issues go, I'd have to also point out that the Concorde is no Kyoto (a penultimate example of exaggerated environmental movement with ulterior political goals). 1960's vintage reheating turbojets are a pretty serious environmental problem.
I mean, it's not particularly environmentally friendly, but it does get something like 14 miles to the gallon per passenger. And it's not like most people use it every day, unlike their SUVs. The total impact on the environment is pretty negligable. And this was effectively killed in the 70s? Yeah right, like the Americans weren't riding around in less efficient cars back then. Don't make me laugh. It was pure politics; pure protectionism. Boeing didn't have a SST (the US spent over a billion trying), so they poisoned the whole supersonic well.
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Nah. Doesn't work. You have to be approximately 1 wavelength away for that to work, in this case we would be millions of wavelengths.
and once the "Rocket" is high enough, why not use more than one transmitter... have the transmitters arranged in consecutive circles.
Provided the rings are within a wavelength of each other; yup. Otherwise, nope; you get a horrible diffraction grating effect and most of the power slops around and probably takes out bystanders.
Just because they can do it, or even if they do it, doesn't mean that it is necessary lawful for them to do it. It may be considered a form of wiretapping, but it would be for the court to decide; I'm not aware of any case law on this.
Like what, the government isn't already part of "anybody"?
We elect "somebody", not "anybody"; if they start acting like they're anybody, then they're history in the long term in any true democracy.
You know, if that fuel is 98% hydrogen peroxide (HTP), then it might even work. Carmack tried to buy some from FMC, $100,000 worth would you believe. They turned him down... He has no source of HTP right now, and he's just run out. Bummer.
You could try running one of those courses I guess.
I don't think I'm going to hold my breath on this. You don't appear to know the difference between energy and fuel, and waving your hand like:
Let's not let excessive details (which apply similarly to both vehicles) obfuscate the elegant simplicity of the rocket equation.
Really doesn't cut it when conventional rockets leave the atmosphere as soon as possible to avoid drag, whereas airbreathing vehicles necessarily sit right in the draggy atmosphere the whole time they are thrusting.
The other factor you've forgotten is thrust:weight ratios. Conventional rocket engines have 100:1 thrust:weight ratios, airbreathing rockets are lucky to get 10:1. That means that the dry weight of the vehicle is 10x higher. That greatly offsets any reduction in fuel use- and LOX/Kerosene fuel is dirt cheap (under $1/kg), whereas the airbreathing mass is typically very expensive. So you've typically swapped cheap fuel for expensive hardware, not good.
Normally when microwaves are used for sending signals, for example satellite TV or point-point transmission, most of the power ends up missing the receiver, but the receiver amplifies the signal using power from the mains.
When you have a rocket, there's obviously no power cord ;-), so you need the vehicle to catch as much of the microwaves as possible.
However, there's a law of nature that says that the maximum focusing you can do is determined by the size of the transmitter antenna and the wavelength of the microwaves you are sending.
So:
angle of transmitted beam (in radians) = 1.22 * wavelength/diameter of antenna
wavelength of 100Ghz microwaves = 300,000,000/100,000,000,000 = 3mm (1/8 of an inch)
Let's make the diameter of transmitter = 10 m (say). (This is a huge transmitter, ~30 feet diameter, reasonably big).
This gives the angle of the beam to be: 1.22 * 0.003/10 = 0.000366 radians
At 200km, this means that the beam is: 200,000 * 0.000366 = 73m wide (~200 feet)
That means that your rocket would have to be 200 feet in diameter to capture most of this energy. Which is very likely to be heavy.
The only way to improve on that is to go to a higher frequency, difficult from 100 Ghz, or make the transmitter bigger, 100 meters (~300 yards?) and bring the rocket down to 7.3m (21 yards) diameter, but it's still all a bit awkward. Oh yeah, and you can't use 'synthetic aperture techniques'- you can't have a few widely spaced transmitters 100m apart, it turns out that doesn't work, you get huge sidebeams that suck away your power and it never reaches the vehicle, and those sidebeams are hazardous.
Still, it might be good for climbing up some way through the atmosphere, and then using a conventional rocket the rest of the way.
Feel free to play with the numbers, I'm not saying it absolutely doesn't work, it certainly works at low altitudes, I'm just trying to demonstrate the difficulties with microwave beamed power in this context.
And because the dry mass of the rocket is the expensive bit, you haven't pushed up the cost of the vehicle by much.
And air is actually a much worse propellent than rocket fuel; you need many times more energy than the better rocket fuels to get the same thrust. That and the fact that airbreathing vehicles make you stay in the atmosphere for longer means you get much more drag- and drag goes up with the square of your velocity- mach 25 is needed for orbit, and people complain about Concorde being inefficient at mach 2!
The problem is that because it is such a heavy atom when you heat it, it ends up moving very slowly. By conservation of momentum, your rocket ends up moving much more slowly than if you had used hydrogen, or even nitrogen for the same mass of fuel (the fuel would be much denser, but still, it turns out to be a big, big loss).
What statement? I said your calculation that you would only need 10% of the energy was bogus; and I stand by that. In externally powered airbreathing rockets as we are discussing here, the energy and the fuel are unrelated; or are only related by the trajectory you've chosen to use.
For a given orbit, provided exhaust velocities are equal, a rocket which does not carry its fuel will always use less fuel.
Trivially true. However, with an airbreathing rocket the last point on its orbit where it burns atmosphere is necessarily within the atmosphere and hence it's orbit will still intersect the atmosphere, and you can't achieve a stable orbit; so you need to carry some fuel with you (there are a few sneaky ways around that, for example doing a slingshot around the moon, but they are often at best rather awkward). Additionally, the whole time you are in the atmosphere you are fighting drag; you absolutely cannot ignore that effect.
A better way for you to argue against a power savings is to point out that there's no way super heated air could ever achieve the exhaust velocity equal to that of kerosine and liquid oxygen.
No, not really. Superheated air can go faster than kerosene and LOX, if you heat it enough. But the molecular mass of nitrogen (air is mostly nitrogen) is pretty high. The exhaust velocity that can be achieved for a particular energy is inversely related with molecular mass, so air is fairly poor in that regard; by way of contrast kerosene has lots of hydrogen in it, and so requires less energy for a given exhaust velocity.
Energy or fuel mass isn't really the problem anyway. More important is the dry mass of your rocket, since that's the bit that costs the most (it turns out surprisingly that fuel is much cheaper than the cost of the vehicle, fuel is less than 1% of the total cost, fabrication of the metal bits and so forth are much more expensive).
That's not actually true at all. For a few reasons:
a) some (a lot) of the energy ends up in moving the exhaust around (for example you have to throw it downwards to get thrust from it- unlike the case where you carry the fuel with you the propellent has to end up moving downwards, since it was stationary when you met it).
b) gravity losses- until you reach orbit you're falling all the time; it costs energy keeping you up until then.
c) aerodynamic drag getting there (a lot, since you need be in the atmosphere to collect your fuel, and you're trying to achieve orbital velocity -mach 25 or so there; normal rockets get out of the atmosphere sharpish to minimise that problem)
d) no air at orbital altitudes; so you need some on-board fuel to circularise your orbit at the very least.
Also, many remotely powered vehicles have high exhaust velocities. That means that the amount of power left in the exhaust is many times greater than in the vehicle (energy efficiency is inversely proportional to exhaust velocity, roughly).
Frankly, I don't see any easy way to work out how energy efficient a system like that would be; it's trajectory specific. It may be more efficient, but certainly not an order of magnitude; and it's quite possible that it's less efficient particularly if the exhaust velocity is very high.
Still, I suppose if it is being NAT'd properly, it maybe ok, I guess [pained look].
That's all a matter of perspective. Some people would much rather build up to a two-hour, vigorous workout than give up beer and pizza.
Yeah, well those people are likely to stay fat; unless they eat those things in moderation, the effect of exercise in the short term is fairly minor, and the effect of eating too much is quite large. The long term is different- in the long term exercise can help keep the weight off, if you keep at it and has other benefits.
Huh? What are you supposed to be balancing it against except your bodies needs? Sure, you don't need to balance every meal. Every day is more like it; the point is to avoid actual deficiencies, because then you will tend to be hungry; or it will affect your health.
Yeah. It helps a bit. But it's still difficult to lose significant weight by exercise.
Secondly, a pound a week is pretty close the fastest rate anybody should lose weight. If you are losing weight much faster than that, all you are mostly dehydrating and/or losing muscle mass, not getting slimmer.
I'm saying losing a pound a week by exercise alone is completely out of the question for 90+% of the population. What you say about losing mass is incorrect; if you are dieting- you are losing muscle mass; it's just a question of proportion. If you diet too fast you will lose 50:50 muscle/fat. If you diet more slowly with a bit of exercise more like 20:80. It's important to do some, but don't ever think that you can lose much weight that way.
Thirdly, it is almost impossible to get proper nutrients if you are only eating 500 calories a day.
Gee. Do you think? ;-) Hey, here's an idea, why don't you read what I wrote? I said cut back BY 500 calories, not TO 500 calories.
You most certainly can lose weight by exercise alone, so long as you're regular food intake is not excessive.
Sure, but it's very slow; far, far under a pound a week unless you are incredibly fit. It may help you keep your weight stable once you get there, and it does tend to maintain muscle mass; but as a way of losing weight; it's pretty sucky.
I don't buy this complex carb theory. It's not how complex the carb is, it's how quickly it is absorbed, and how good for you the food is. Maltodextrin is a complex carb, but is absorbed the most quickly of any carbohydrate.
Check out the Glycemic Index (GI). If you eat mainly low GI foods, you will generally be less hungry, and your body will have more time to deal with the carbs without turning them into fat.
Eating some fruit every day is great. However if you eat a lot of fruit every day, then it's probably bad for you (e.g. a dozen tangerines).
However, fat is far worse than anything. Avoid fats, they have no nutritional value. Therfore, you should not eat loads of bacon everyday. Eggs, the whites are good for you, the yolks are full of calories and fats. Again, avoid fats.
Nope. Fats are essential for life. A whole egg per day is GOOD for you. (Some early research said otherwise, however it turned out they were using dried eggs, fresh eggs turn out to be ok, and contain vitamins). However you should definitely minimise saturated and hydrogenated fats. Unsaturated should be eaten in moderation, and monounsaturated- eat lots of that.
Meats --- lean meats can provide a great source of long-term energy.
Yeah lean meat is good; fish (particularly oily fish) is as good or better.
- enough protein
- some fat (olive oil, almonds, oily fish, pine nut kernels)
- not too many carbs (enough for whatever exercise you are doing)
- plenty, plenty of vegetables (cooked till water changes colour is much better than uncooked)
- some fruit
The point is that when people are hungry; sometimes they really are lacking in something. If you aren't eating a balanced diet you will tend to feel hungry because your body needs something. And that is more likely when you are on a diet.
On the other hand, if you cut back 500 calories a day then you will lose a pound a week. That's much less than 1/4 of most peoples food.
You're wisest to combine the two, exercise and dieting. But of the two, reducing food intake is absolutely critical, exercise merely helps. You basically can't lose weight solely by exercise; well not unless you are incredibly fit to start with, which most people certainly aren't.
Didn't know a lung weighed that much. You live and learn I guess.
That's a shitload of exercise (technical term). Probably 95% of the population simply can't do that much exercise. You're probably genetically lucky; and/or you have been training for a very long time.
Aim for 1.5-2g of protein per pound of lean bodyweight.
You don't need to eat that much protein. The studies suggest that about 1.5g per kg of bodyweight is plenty; and once you have trained you need less, since your body recycles the protein. (Proteins get damaged during exercise, but it gets recycled, and as you train, your body gets better at doing that.)
Your goal (for men) should be to drop your body fat percentage to well under 10% (under 15% for women).
Yeah, well you could do that. But most women have difficulty going below 30%.
Many Histories says we got here by many prior paths that coallesced. That much is essentially certain. Many Worlds says that here isn't the only point- there are many other parallel universes out there too that we can't reach.
Most top physicists agree with Many Histories; it's more or less a consensus position. Many Worlds is a bit more controversial.
There is actually evidence FOR multiverses.
Consider the twin slit experiment. You shine single photons through the slits, and they arrive in a single photon in a well defined location.
And yet there are places where it never arrives. These places suggest that single photon has somehow travelled through BOTH slits and destructively interfered on arrival. Essentially all generally accepted interpretations of QM say that this is what happened in fact.
The simplest theory for this is the 'many histories' theory where the universe has effectively split into two and then recombined to give one universe again; and triggered the interference patterns whilst doing it. (The many worlds theory expresses this in terms of wavefunction rather than universes but the effect is the same).
Trouble is; if it could split twice, why couldn't it split 3 times or 4 or a million times? Perhaps it did- perhaps we only see the universe which precedes our own, the others are elsewhere diverging slowly away...
And there's another problem; how do you explain what happened to the universes we never saw? They certainly should have happened, and to the extent that we can see them, we do see them; so assuming that they don't exist probably requires an act of faith.
Yes, it would be a declarative language. No, it would not be necessarily like, say, Prolog; although you might be able to implement it in a language like Prolog.
The easiest way to make it parallisable would be to only allow expressions with no side effects, so passive function application would have to be the primary means of computation.
You could certainly express the specification in a functional language. But it's unnecessary, exploring program space is highly parallelisable without much communication so it doesn't get you far.
The point is not to write a program in a declarative language. The point is to write a specification in a declarative language that describes the behaviour of a program to quickly solve a class of problems. If you want to look at this as a prolog compiler on steroids, then I think you're not entirely wrong, but you've missed the spirit of the idea.
Just because something is equivalent to a compiled Prolog program doesn't mean that's the best way to implement it; on the other hand it doesn't mean it isn't either. (Actually, since Prolog is Turing complete, everything is equivalent to a compiled Prolog program, that's partly why I think you've got the wrong end of the stick.)
Concorde (and SST) died way back in the 70s; way before 9/11. And a lot of that was American protectionism.
So say you want a chess program. You feed in the rules of the game in a special language, and it generates a program to play by searching for the program that successfully implements that.
That sounds fantastic! You'll never have to write another line of code ever again!
Hold on, don't get excited, it's not that simple.
First, just because it plays a game of chess, doesn't mean it plays a good game of chess, so you might still have to tell it in quite high detail what 'good' means in terms of your program specification.
Secondly, it's very easy to tell it the specification incorrectly. Specification errors are very common in computer software already, and having the highly precise specification language that you'll need doesn't make it easier, although the machine is less likely to screw up the implementation, so you're still better off than coding by hand.
Still, in some cases, where the problem is easy to state, you should have a solution program in just a few minutes; whereas now it could take hours or days.
Anyway that's where I see it go. There are some existing implementations of this kind of thing out there already, but they tend to be small. For example somebody wrote a program to find the shortest program to perform certain operations for gcc backends. You pretty much just point the compiler at a new processor and optimum code pops out, it's kind of neat. But currently this is limited to maybe 15 instructions long. I think that this will grow enormously, particularly if you throw away the constraint of having to be completely optimal, and allow 'only slightly suboptimal' programs; and faster and faster processors are coming down the pipe; so 'searching for code' is becoming more practical.
Oh yeah, and the idea probably works for parallel and quantum computers too. Parallel searching for optimum parallel code, and so forth.
Nothing at all, really, except in the most trivial sense of triggering it's final demise. The big, huge problem was that the aircraft never sold. Otherwise they might still be building them. And it never sold due to exagerated environmental concerns.
As exaggerated environmental issues go, I'd have to also point out that the Concorde is no Kyoto (a penultimate example of exaggerated environmental movement with ulterior political goals). 1960's vintage reheating turbojets are a pretty serious environmental problem.
I mean, it's not particularly environmentally friendly, but it does get something like 14 miles to the gallon per passenger. And it's not like most people use it every day, unlike their SUVs. The total impact on the environment is pretty negligable. And this was effectively killed in the 70s? Yeah right, like the Americans weren't riding around in less efficient cars back then. Don't make me laugh. It was pure politics; pure protectionism. Boeing didn't have a SST (the US spent over a billion trying), so they poisoned the whole supersonic well.