This is the inspiration for the name, from a book by Arthur Eddington:
"In ancient days two aviators procured to themselves wings. Daedalus flew safely through the middle air and was duly honoured on his landing. Icarus soared upwards to the sun till the wax melted which bound his wings and his flight ended in fiasco. In weighing their achievements, there is something to be said for Icarus. The classical authorities tell us that he was only “doing a stunt”, but I prefer to think of him as the man who brought to light a serious constructional defect in the flying-machines of his day. So, too, in Science. Cautious Daedalus will apply his theories where he feels confident they will safely go; but by his excess of caution their hidden weaknesses remain undiscovered. Icarus will strain his theories to the breaking-point till the weak joints gape. For the mere adventure? Perhaps partly; this is human nature. But if he is destined not yet to reach the sun and solve finally the riddle of its constitution, we may at least hope to learn from his journey some hints to build a better machine."
And if you read Ludwig von Mises' Human Action, that's almost exactly the point he is making.
A lot of people here are talking about the amount of math needed in economics - and they're right as far as mainstream econ goes. But Mises took the a priori approach. His work reads like a philosophy text, not a math book.
Like it or loathe it (and I happen to like his approach - even if I don't agree with all his conclusions), Mises' economics has little in common with the mainstream stuff.
About the only way I can think of doing this is to 'evolve' the robot's software in a virtual reality environment. Throw a huge number of scenarios at it. Reject any builds that result in a violation of the laws, and evolve only from those that are most compliant.
Doesn't guarantee that the robot will always follow the laws in every possible situation, but at least it seems like a plausible method of maximising compliance.
He thinks he's totally discredited this article by
pointing out that solar satellites would use solar cells instead of
mirrors and boilers. Actually, in high-power designs, boilers and
turbines have surprisingly good efficiency, much better than the 15% he
quotes for solar cells, which waste the majority of the light which
strikes them because the frequency is wrong. That's not where I think
the efficiency problem lies, anyway. The problem is the power downlink
to the ground, especially the conversion to RF and back to electricity
in the receiver. They'll both be terrible.
He thinks he's found a citation for 90% efficiency in
conversion of DC to microwave RF. Unfortunately, what he has found
isn't relevant to this problem. It's easy to do that if you're only
talking about a few watts. It is not at all easy if you're talking a
gigawatt. No one is going to get 90% conversion of electric power to
microwave transmission at gigawatt power levels. No one is going to
come remotely close.
This is one of the few remaining applications where
semiconductors have not yet displaced vacuum tubes. In a modern TV
transmitter rated for 500 KW or 1 MW, everything is transistorized
right up to the very last amplification stage, which uses vacuum tubes
the size of garbage cans.
The satellite downlink will have to generate and
transmit as much RF as a thousand such TV stations. Doing that is
difficult. Doing that with 90% efficiency is "nontrivial".
Doing it at microwave frequencies merely adds to the
fun, because extremely high frequency applications are also extremely
unforgiving. I'm not really sure just how you'd generate microwave RF
at gigawatt power levels, quite frankly, but whatever approach gets
used, it ain't gonna achieve 90% conversion. Not gonna happen.
Lutas concludes, SDB took on an almost impossible task, proving that something cannot be done feasibly.
No, I'm afraid not. I don't contend that these things are and will
always remain infeasible (though the ones I discussed are definitely
infeasible right now). What I contend that they cannot be done soon
enough, large enough, to have any political effect on this war.
I'm not claiming he's right. But his arguments deserve proper consideration.
Well, here's a critique of the idea from someone who can't in any way be fitted into those categories:
USS Clueless
[...] When it comes to power generation, the job's not done until the
energy reaches the end user. The challenge of energy delivery is
particularly severe for solar satellite technology.
Generally speaking, every time energy is converted from one form to
another a lot of it will be lost (because of the Second Law of
Thermodynamics). All technologies which generate power and deliver it
to end users involve such conversions. A coal-fired electrical
generation plant burns coal to produce heat, converts heat to pressure
by applying a lot of that heat to a boiler to produce steam, converts
pressure into mechanical motion (with a turbine), converts mechanical
motion into electricity (with a dynamo), and then delivers the
electricity with long distance power lines, which usually requires
multiple voltage/current conversions using transformers or
motor-generators. Many of those conversions are very efficient but some
of them involve pretty significant losses.
The efficiencies of every step have to be multiplied together to
calculate the overall system efficiency. If you have five steps and
each one wastes 20%, then each step has an efficiency of 0.8, and the
overall system efficiency will be 0.8*0.8*0.8*0.8*0.8 == 0.328, meaning
about 33% of the original energy would be delivered to end users, with
the remaining 67% being lost. But if each of those five steps wasted
30% instead of 20%, the overall system would only deliver 17% of the
original energy. The more conversions required, and the worse the
efficiency on those conversions, then the lower the efficiency of the
overall system.
Solar satellite power generation is particularly poor in this
regard. Sunlight is concentrated using mirrors (with some losses) onto
a boiler (with some of the light reflecting instead of being converted
to heat, and some of the heat radiating away via black-box radiation).
The next few steps are the same as for a coal plant: steam drives a
turbine, which drives a dynamo, which generates electricity. At that
point, all you have to do is to deliver it, but that is not easy with
solar satellites.
The electric power would have to be converted to microwaves (with a
lot of losses). That would be beamed down to earth (with losses from
atmospheric reflection, scattering and absorption). Most of the beam
would strike the receiver but some would not because of beam spreading.
(Also, there beam would tend to wander a bit because of atmospheric
refraction, which also makes stars "twinkle".) The receiver would have
to capture the microwaves that struck it and somehow convert back into
electricity, and every way I know to do this has dreadfully poor yields.
Microwaves are not the only approach to the downlink, but every
approach I know of for the downlink either cannot handle the power
levels involved, or is terribly inefficient. Compared to terrestrial
electrical power generation technologies, solar satellites inherently
require more conversions, many of which have poor efficiency, and the
overall system efficiency will necessarily be far worse. I would be
surprised if the system had a yield as high as 5%. I would tend to
think it would be even lower.
On the other hand, the energy which would have to be expended to
create a solar power satellite would be huge compared to the energy
needed to build a terrestrial power generation facility. Would it break
even before it reached the end of its operating life? Would it actually
produce more energy than it cost? I'm not so sure it would.
The capital cost to create a solar satellite would also dwarf the
cost of terrestrial power plants which delivered comparable amounts of
power, but the satellites and terrestrial power generators would sell
their power on the same market at the same price. Could a solar
satellite produce enough revenue during its o
Scaled Composites and Armadillo are great teams, but don't forget StarChaser, the British team who have already accomplished a heck of a lot, and have started building their X-Prize rocket.
They're realistic; they know that SC is possibly close to winning the prize, but they haven't won it yet. StarChaser is currently focussing on the X-Prize, but their plan doesn't rely on the prize itself. They recognise that whoever wins the prize, the publicity generated will help open up the market for space tourism and (more generally) private micro-satellite launches.
StarChaser's design has been deliberately designed with scalability in mind; it won't require immense amounts of work to build bigger versions. This is all part of their long-term plan. After all, they were in the business before the X-Prize was announced.
StarChaser, Scaled and Armadillo are all doing great work. Best of luck to all of them, whoever ends up getting the prize.
Even though I know calculus pretty darn well, after reading Seife's discussion of the development of 'limits', I realised that I hadn't truly 'grokked' it as well as I'd thought.
The book includes a fascinating account of just how tantalisingly close the Greeks came to inventing calculus. One can only wonder what would've happened if they'd done it.
there is always 100% energy transfer, just that not all of it is necessarily *useful*
But the point is that 'usefulness' and 'entropy' are concepts that only make sense at the macro level, when there are large ensembles of particles involved.
If one were to talk about these things in the context of individual particles, one might as well start discussing the literary merit of a single punctuation mark plucked out of some text with no context.
You're right, ebooks won't replace paper books. But there are genuine advantages to them.
I store lots of books (40+) on my Palm; some of these are really huge texts (1000+ pages) in paper. But on a Palm it makes no difference at all.
And I can read a little at a time, whenever there's a spare moment; in a long queue at the supermarket, waiting for something to compile etc. It's like recycling all those otherwise wasted bits of time.
The other advantages are psychological. In normal books, I have a real problem with keeping my focus on the text I'm actually reading. As soon as I turn a page, my eyes flick down to the end of the next page, breaking my flow. Because of the small screen, I've got only a few sentences visible at any time so I can't inadvertently skip forward.
The other psychological benefit is a bit harder to explain. With a normal big paper book, it's quite a daunting feeling to see how little progress I've made after reading for quite some time. This can end up deterring me from reading the rest of the book. But on the Palm (and particularly with iSilo) there's a sense of progress through the chapter, not the whole book. So even a couple of minutes reading feels like it's made a dent.
There's a huge collection of ebooks available at Memoware, many of them converted by me!:-)
Re:well, of course...
on
E ~ mc^2
·
· Score: 3, Informative
I think you're thinking of the expansion of E=mc^2/sqrt(1-v^2/c^2), which produces
E=m c^2 + 0.5 m v^2 +...
where m is the rest mass. This is a beautiful piece of math. It shows that the kinetic energy that we already knew about (0.5 m v^2) is actually an artefact of the relativistic change in mass.
The rest of the terms are negligible for low v, which is why we never noticed it in the lab before Einstein.
It's not like Tito pushed the money into the vacuum of space
Actually, that wouldn't necessarily have been unproductive. Destroying money is not the same as destroying actual wealth.
If you burn $100 million in your back yard, then the rest of the dollar-holding world is $100 million better off. That's a marginal difference to each person, but there is no actual wealth destruction involved.
Stephen Landsburg provides a good discussion of this in his book The Armchair Economist.
Slashdot Mirror
You're right, but I think Eddington was using poetic licence to illustrate a point. And at least Icarus was trying out his novel theory on himself! :-)
This is the inspiration for the name, from a book by Arthur Eddington: "In ancient days two aviators procured to themselves wings. Daedalus flew safely through the middle air and was duly honoured on his landing. Icarus soared upwards to the sun till the wax melted which bound his wings and his flight ended in fiasco. In weighing their achievements, there is something to be said for Icarus. The classical authorities tell us that he was only “doing a stunt”, but I prefer to think of him as the man who brought to light a serious constructional defect in the flying-machines of his day. So, too, in Science. Cautious Daedalus will apply his theories where he feels confident they will safely go; but by his excess of caution their hidden weaknesses remain undiscovered. Icarus will strain his theories to the breaking-point till the weak joints gape. For the mere adventure? Perhaps partly; this is human nature. But if he is destined not yet to reach the sun and solve finally the riddle of its constitution, we may at least hope to learn from his journey some hints to build a better machine."
And if you read Ludwig von Mises' Human Action, that's almost exactly the point he is making.
A lot of people here are talking about the amount of math needed in economics - and they're right as far as mainstream econ goes. But Mises took the a priori approach. His work reads like a philosophy text, not a math book.
Like it or loathe it (and I happen to like his approach - even if I don't agree with all his conclusions), Mises' economics has little in common with the mainstream stuff.
You sure your mate doesn't mind being used as a hardware component?
;-)
What are you talking about?
The question asked was how the job could be accomplished. That's what I attempted to answer.
Whether it should be done or not is a completely different (and irrelevant) question.
About the only way I can think of doing this is to 'evolve' the robot's software in a virtual reality environment. Throw a huge number of scenarios at it. Reject any builds that result in a violation of the laws, and evolve only from those that are most compliant.
Doesn't guarantee that the robot will always follow the laws in every possible situation, but at least it seems like a plausible method of maximising compliance.
Did you not read the complete linked article?
I'm not claiming he's right. But his arguments deserve proper consideration.
Well, here's a critique of the idea from someone who can't in any way be fitted into those categories: USS Clueless
Scaled Composites and Armadillo are great teams, but don't forget StarChaser, the British team who have already accomplished a heck of a lot, and have started building their X-Prize rocket.
They're realistic; they know that SC is possibly close to winning the prize, but they haven't won it yet. StarChaser is currently focussing on the X-Prize, but their plan doesn't rely on the prize itself. They recognise that whoever wins the prize, the publicity generated will help open up the market for space tourism and (more generally) private micro-satellite launches.
StarChaser's design has been deliberately designed with scalability in mind; it won't require immense amounts of work to build bigger versions. This is all part of their long-term plan. After all, they were in the business before the X-Prize was announced.
StarChaser, Scaled and Armadillo are all doing great work. Best of luck to all of them, whoever ends up getting the prize.
I agree. That's a great book.
Even though I know calculus pretty darn well, after reading Seife's discussion of the development of 'limits', I realised that I hadn't truly 'grokked' it as well as I'd thought.
The book includes a fascinating account of just how tantalisingly close the Greeks came to inventing calculus. One can only wonder what would've happened if they'd done it.
You know, every time I heard that 'pip' I wondered why they put it in, as I'd never heard it on a real phone.
Cheers!
It's worth mentioning that although it's true that Mercury is tidal-locked with the sun, it's in a 3:2 lock, not 1:1.
This means that it does rotate relative to the sun, so there's no permanent "dark side".
(For comparison, the moon is tidal-locked 1:1 with Earth, so we never see the far side.)
And so did I. Oh well.
http://torrent.andrewhitchcock.org/files/Maestro-W in.exe.torrent
You had an extra space in there.
Cheers!
there is always 100% energy transfer, just that not all of it is necessarily *useful*
But the point is that 'usefulness' and 'entropy' are concepts that only make sense at the macro level, when there are large ensembles of particles involved.
If one were to talk about these things in the context of individual particles, one might as well start discussing the literary merit of a single punctuation mark plucked out of some text with no context.
Old notes aren't 'legal tender'; if you owe someone £20, they can legitimately refuse to accept an old £20 note.
However, you're right that the central bank will continue to accept and exchange old notes at their face value.
I store lots of books (40+) on my Palm; some of these are really huge texts (1000+ pages) in paper. But on a Palm it makes no difference at all.
And I can read a little at a time, whenever there's a spare moment; in a long queue at the supermarket, waiting for something to compile etc. It's like recycling all those otherwise wasted bits of time.
The other advantages are psychological. In normal books, I have a real problem with keeping my focus on the text I'm actually reading. As soon as I turn a page, my eyes flick down to the end of the next page, breaking my flow. Because of the small screen, I've got only a few sentences visible at any time so I can't inadvertently skip forward.
The other psychological benefit is a bit harder to explain. With a normal big paper book, it's quite a daunting feeling to see how little progress I've made after reading for quite some time. This can end up deterring me from reading the rest of the book. But on the Palm (and particularly with iSilo) there's a sense of progress through the chapter, not the whole book. So even a couple of minutes reading feels like it's made a dent.
There's a huge collection of ebooks available at Memoware, many of them converted by me! :-)
I think you're thinking of the expansion of E=mc^2/sqrt(1-v^2/c^2), which produces
E=m c^2 + 0.5 m v^2 + ...
where m is the rest mass. This is a beautiful piece of math. It shows that the kinetic energy that we already knew about (0.5 m v^2) is actually an artefact of the relativistic change in mass.
The rest of the terms are negligible for low v, which is why we never noticed it in the lab before Einstein.
Actually, that wouldn't necessarily have been unproductive. Destroying money is not the same as destroying actual wealth.
If you burn $100 million in your back yard, then the rest of the dollar-holding world is $100 million better off. That's a marginal difference to each person, but there is no actual wealth destruction involved.
Stephen Landsburg provides a good discussion of this in his book The Armchair Economist.
Wasn't it Einstein who said "Things should be made as simple as possible - but no simpler." ?