Čudeži in znanost

Prapok, vesolje, kozmologija, črne luknje...
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bargo
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Pridružen: 3.11.2004 22:41

Re: Čudeži in znanost

Odgovor Napisal/-a bargo »

vojko napisal/-a:
bargo napisal/-a: Me zanima, kako bi to razložil PEK. Ob vinu, z rozinami, sirom in luknjami, ...
Zanimivo, zagonetno...
Hvala. Veš, vino je pravzaprav tisto z mehurčki, kjer združuješ staro in novo, da nastanejo luknje v trdnosti. :D Na dnu flaše je kupola, da je ne raznese! Lok, ki obteži in tako ojača dva razmajana stebra, saj se spomniš.
vojko napisal/-a: Tvoja Rešitev je seveda rešitev, kot jo vidi informatik.
Ne, računalničar vidi tako. Informatik vidi zagonetno, kamor koli pogleda, sama čudesa. :wink: Saj se spomniš, da Informatik pravi "Informacije niso humane", kar te je šokiralo. Šele vstavljena, urejena, ovrednotena in pomensko urejena informacija je človeška, vidiš, tudi zato ima znanje mero človečnosti. :wink:

Informatik se zaveda nastajanja informaciji, ne podatkov, zato je zelo pozoren, senzibilen, pri ločevanju podatkov od informacij. "Si mi skoraj skuril možgane", se spomniš.
Samo tako je mogoče ločiti, kaj dejansko je skladno z okoljem v katerem je oddajnik in kaj je samo šum v komunikaciji.

Drugače povedano, vsak podatek ni informacija, če pa oddani podatek postane vhodna informacija, potem za računalničarja to predstavlja velik problem, spremeniti mora model, pri čemer mora obdržati vse stare funkcionalnosti. Sprememba, ki povzroči razliko. Kdo bo plačal vso to delo, je potem vprašanje za pravnike.

Za fizika je ta transformacija lahko neke vrste blagoslov, ker ta zmeraj pričakuje podatke, ki bodo potrdili njegov model. Skratka vernik. :wink:
Ko narava zazna njegovo zagato, mu vrača to kar je želel dobiti, potem je konec objektivnosti in začne se inter-subjektivnost.
vojko napisal/-a: Ima ZF novela (po oceni mnogih sploh najboljša, kar jih je bilo napisanih v tem žanru) Isaaca Asimova The Last Question (prevod sem objavil na enem od forumov Kvarkadabre) s tvojim razmišljanjem kakšno podobnost?
Mogoče, vendar ne poznam te knjige, mogoče najdeš in podaš link do prevoda. :P

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Re: Čudeži in znanost

Odgovor Napisal/-a vojko »

bargo napisal/-a:
vojko napisal/-a:
bargo napisal/-a: Me zanima, kako bi to razložil PEK. Ob vinu, z rozinami, sirom in luknjami, ...
Zanimivo, zagonetno...
Hvala. Veš, vino je pravzaprav tisto z mehurčki, kjer združuješ staro in novo, da nastanejo luknje v trdnosti. :D Na dnu flaše je kupola, da je ne raznese! Lok, ki obteži in tako ojača dva razmajana stebra, saj se spomniš.
vojko napisal/-a: Tvoja Rešitev je seveda rešitev, kot jo vidi informatik.
Ne, računalničar vidi tako. Informatik vidi zagonetno, kamor koli pogleda, sama čudesa. :wink: Saj se spomniš, da Informatik pravi "Informacije niso humane", kar te je šokiralo. Šele vstavljena, urejena, ovrednotena in pomensko urejena informacija je človeška, vidiš, tudi zato ima znanje mero človečnosti. :wink:

Informatik se zaveda nastajanja informaciji, ne podatkov, zato je zelo pozoren, senzibilen, pri ločevanju podatkov od informacij.
Samo tako je mogoče ločiti, kaj dejansko je skladno z okoljem v katerem je oddajnik in kaj je samo šum v komunikaciji.

Drugače povedano, vsak podatek ni informacija, če pa oddani podatek postane vhodna informacija, potem za računalničarja to predstavlja velik problem, spremeniti mora model, pri čemer mora obdržati vse stare funkcionalnosti. Sprememba, ki povzroči razliko. Kdo bo plačal vso to delo, je potem vprašanje za pravnike.

Za fizika je ta transformacija lahko neke vrste blagoslov, ker ta zmeraj pričakuje podatke, ki bodo potrdili njegov model. Skratka vernik. :wink:
Ko narava zazna njegovo zagato, mu vrača to kar je želel dobiti, potem je konec objektivnosti in začne se inter-subjektivnost.
vojko napisal/-a: Ima ZF novela (po oceni mnogih sploh najboljša, kar jih je bilo napisanih v tem žanru) Isaaca Asimova The Last Question (prevod sem objavil na enem od forumov Kvarkadabre) s tvojim razmišljanjem kakšno podobnost?
Mogoče, vendar ne poznam te knjige, mogoče najdeš in podaš link do prevoda. :P
V originalu ti jo navajam tule, prevod pa je bil objavljen v ŽiT št. 11/68.

The Last Question by Isaac Asimov © 1956

The last question was asked for the first time, half in jest, on May 21, 2061, at a time when humanity first stepped into the light. The question came about as a result of a five dollar bet over highballs, and it happened this way:
Alexander Adell and Bertram Lupov were two of the faithful attendants of Multivac. As well as any human beings could, they knew what lay behind the cold, clicking, flashing face -- miles and miles of face -- of that giant computer. They had at least a vague notion of the general plan of relays and circuits that had long since grown past the point where any single human could possibly have a firm grasp of the whole.

Multivac was self-adjusting and self-correcting. It had to be, for nothing human could adjust and correct it quickly enough or even adequately enough -- so Adell and Lupov attended the monstrous giant only lightly and superficially, yet as well as any men could. They fed it data, adjusted questions to its needs and translated the answers that were issued. Certainly they, and all others like them, were fully entitled to share In the glory that was Multivac's.

For decades, Multivac had helped design the ships and plot the trajectories that enabled man to reach the Moon, Mars, and Venus, but past that, Earth's poor resources could not support the ships. Too much energy was needed for the long trips. Earth exploited its coal and uranium with increasing efficiency, but there was only so much of both.

But slowly Multivac learned enough to answer deeper questions more fundamentally, and on May 14, 2061, what had been theory, became fact.

The energy of the sun was stored, converted, and utilized directly on a planet-wide scale. All Earth turned off its burning coal, its fissioning uranium, and flipped the switch that connected all of it to a small station, one mile in diameter, circling the Earth at half the distance of the Moon. All Earth ran by invisible beams of sunpower.

Seven days had not sufficed to dim the glory of it and Adell and Lupov finally managed to escape from the public function, and to meet in quiet where no one would think of looking for them, in the deserted underground chambers, where portions of the mighty buried body of Multivac showed. Unattended, idling, sorting data with contented lazy clickings, Multivac, too, had earned its vacation and the boys appreciated that. They had no intention, originally, of disturbing it.

They had brought a bottle with them, and their only concern at the moment was to relax in the company of each other and the bottle.

"It's amazing when you think of it," said Adell. His broad face had lines of weariness in it, and he stirred his drink slowly with a glass rod, watching the cubes of ice slur clumsily about. "All the energy we can possibly ever use for free. Enough energy, if we wanted to draw on it, to melt all Earth into a big drop of impure liquid iron, and still never miss the energy so used. All the energy we could ever use, forever and forever and forever."

Lupov cocked his head sideways. He had a trick of doing that when he wanted to be contrary, and he wanted to be contrary now, partly because he had had to carry the ice and glassware. "Not forever," he said.

"Oh, hell, just about forever. Till the sun runs down, Bert."

"That's not forever."

"All right, then. Billions and billions of years. Twenty billion, maybe. Are you satisfied?"

Lupov put his fingers through his thinning hair as though to reassure himself that some was still left and sipped gently at his own drink. "Twenty billion years isn't forever."

"Will, it will last our time, won't it?"

"So would the coal and uranium."

"All right, but now we can hook up each individual spaceship to the Solar Station, and it can go to Pluto and back a million times without ever worrying about fuel. You can't do THAT on coal and uranium. Ask Multivac, if you don't believe me."

"I don't have to ask Multivac. I know that."

"Then stop running down what Multivac's done for us," said Adell, blazing up. "It did all right."

"Who says it didn't? What I say is that a sun won't last forever. That's all I'm saying. We're safe for twenty billion years, but then what?" Lupov pointed a slightly shaky finger at the other. "And don't say we'll switch to another sun."

There was silence for a while. Adell put his glass to his lips only occasionally, and Lupov's eyes slowly closed. They rested.

Then Lupov's eyes snapped open. "You're thinking we'll switch to another sun when ours is done, aren't you?"

"I'm not thinking."

"Sure you are. You're weak on logic, that's the trouble with you. You're like the guy in the story who was caught in a sudden shower and Who ran to a grove of trees and got under one. He wasn't worried, you see, because he figured when one tree got wet through, he would just get under another one."

"I get it," said Adell. "Don't shout. When the sun is done, the other stars will be gone, too."

"Darn right they will," muttered Lupov. "It all had a beginning in the original cosmic explosion, whatever that was, and it'll all have an end when all the stars run down. Some run down faster than others. Hell, the giants won't last a hundred million years. The sun will last twenty billion years and maybe the dwarfs will last a hundred billion for all the good they are. But just give us a trillion years and everything will be dark. Entropy has to increase to maximum, that's all."

"I know all about entropy," said Adell, standing on his dignity.

"The hell you do."

"I know as much as you do."

"Then you know everything's got to run down someday."

"All right. Who says they won't?"

"You did, you poor sap. You said we had all the energy we needed, forever. You said 'forever.'"

"It was Adell's turn to be contrary. "Maybe we can build things up again someday," he said.

"Never."

"Why not? Someday."

"Never."

"Ask Multivac."

"You ask Multivac. I dare you. Five dollars says it can't be done."

Adell was just drunk enough to try, just sober enough to be able to phrase the necessary symbols and operations into a question which, in words, might have corresponded to this: Will mankind one day without the net expenditure of energy be able to restore the sun to its full youthfulness even after it had died of old age?

Or maybe it could be put more simply like this: How can the net amount of entropy of the universe be massively decreased?

Multivac fell dead and silent. The slow flashing of lights ceased, the distant sounds of clicking relays ended.

Then, just as the frightened technicians felt they could hold their breath no longer, there was a sudden springing to life of the teletype attached to that portion of Multivac. Five words were printed: INSUFFICIENT DATA FOR MEANINGFUL ANSWER.

"No bet," whispered Lupov. They left hurriedly.

By next morning, the two, plagued with throbbing head and cottony mouth, had forgotten about the incident.



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Jerrodd, Jerrodine, and Jerrodette I and II watched the starry picture in the visiplate change as the passage through hyperspace was completed in its non-time lapse. At once, the even powdering of stars gave way to the predominance of a single bright marble-disk, centered.
"That's X-23," said Jerrodd confidently. His thin hands clamped tightly behind his back and the knuckles whitened.

The little Jerrodettes, both girls, had experienced the hyperspace passage for the first time in their lives and were self-conscious over the momentary sensation of inside-outness. They buried their giggles and chased one another wildly about their mother, screaming, "We've reached X-23 -- we've reached X-23 -- we've ----"

"Quiet, children," said Jerrodine sharply. "Are you sure, Jerrodd?"

"What is there to be but sure?" asked Jerrodd, glancing up at the bulge of featureless metal just under the ceiling. It ran the length of the room, disappearing through the wall at either end. It was as long as the ship.

Jerrodd scarcely knew a thing about the thick rod of metal except that it was called a Microvac, that one asked it questions if one wished; that if one did not it still had its task of guiding the ship to a preordered destination; of feeding on energies from the various Sub-galactic Power Stations; of computing the equations for the hyperspacial jumps.

Jerrodd and his family had only to wait and live in the comfortable residence quarters of the ship.

Someone had once told Jerrodd that the "ac" at the end of "Microvac" stood for "analog computer" in ancient English, but he was on the edge of forgetting even that.

Jerrodine's eyes were moist as she watched the visiplate. "I can't help it. I feel funny about leaving Earth."

"Why for Pete's sake?" demanded Jerrodd. "We had nothing there. We'll have everything on X-23. You won't be alone. You won't be a pioneer. There are over a million people on the planet already. Good Lord, our great grandchildren will be looking for new worlds because X-23 will be overcrowded."

Then, after a reflective pause, "I tell you, it's a lucky thing the computers worked out interstellar travel the way the race is growing."

"I know, I know," said Jerrodine miserably.

Jerrodette I said promptly, "Our Microvac is the best Microvac in the world."

"I think so, too," said Jerrodd, tousling her hair.

It was a nice feeling to have a Microvac of your own and Jerrodd was glad he was part of his generation and no other. In his father's youth, the only computers had been tremendous machines taking up a hundred square miles of land. There was only one to a planet. Planetary ACs they were called. They had been growing in size steadily for a thousand years and then, all at once, came refinement. In place of transistors had come molecular valves so that even the largest Planetary AC could be put into a space only half the volume of a spaceship.

Jerrodd felt uplifted, as he always did when he thought that his own personal Microvac was many times more complicated than the ancient and primitive Multivac that had first tamed the Sun, and almost as complicated as Earth's Planetary AC (the largest) that had first solved the problem of hyperspatial travel and had made trips to the stars possible.

"So many stars, so many planets," sighed Jerrodine, busy with her own thoughts. "I suppose families will be going out to new planets forever, the way we are now."

"Not forever," said Jerrodd, with a smile. "It will all stop someday, but not for billions of years. Many billions. Even the stars run down, you know. Entropy must increase."

"What's entropy, daddy?" shrilled Jerrodette II.

"Entropy, little sweet, is just a word which means the amount of running-down of the universe. Everything runs down, you know, like your little walkie-talkie robot, remember?"

"Can't you just put in a new power-unit, like with my robot?"

The stars are the power-units, dear. Once they're gone, there are no more power-units."

Jerrodette I at once set up a howl. "Don't let them, daddy. Don't let the stars run down."

"Now look what you've done, " whispered Jerrodine, exasperated.

"How was I to know it would frighten them?" Jerrodd whispered back.

"Ask the Microvac," wailed Jerrodette I. "Ask him how to turn the stars on again."

"Go ahead," said Jerrodine. "It will quiet them down." (Jerrodette II was beginning to cry, also.)

Jarrodd shrugged. "Now, now, honeys. I'll ask Microvac. Don't worry, he'll tell us."

He asked the Microvac, adding quickly, "Print the answer."

Jerrodd cupped the strip of thin cellufilm and said cheerfully, "See now, the Microvac says it will take care of everything when the time comes so don't worry."

Jerrodine said, "and now children, it's time for bed. We'll be in our new home soon."

Jerrodd read the words on the cellufilm again before destroying it: INSUFFICIENT DATA FOR A MEANINGFUL ANSWER.

He shrugged and looked at the visiplate. X-23 was just ahead.



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VJ-23X of Lameth stared into the black depths of the three-dimensional, small-scale map of the Galaxy and said, "Are we ridiculous, I wonder, in being so concerned about the matter?"
MQ-17J of Nicron shook his head. "I think not. You know the Galaxy will be filled in five years at the present rate of expansion."

Both seemed in their early twenties, both were tall and perfectly formed.

"Still," said VJ-23X, "I hesitate to submit a pessimistic report to the Galactic Council."

"I wouldn't consider any other kind of report. Stir them up a bit. We've got to stir them up."

VJ-23X sighed. "Space is infinite. A hundred billion Galaxies are there for the taking. More."

"A hundred billion is not infinite and it's getting less infinite all the time. Consider! Twenty thousand years ago, mankind first solved the problem of utilizing stellar energy, and a few centuries later, interstellar travel became possible. It took mankind a million years to fill one small world and then only fifteen thousand years to fill the rest of the Galaxy. Now the population doubles every ten years --"

VJ-23X interrupted. "We can thank immortality for that."

"Very well. Immortality exists and we have to take it into account. I admit it has its seamy side, this immortality. The Galactic AC has solved many problems for us, but in solving the problems of preventing old age and death, it has undone all its other solutions."

"Yet you wouldn't want to abandon life, I suppose."

"Not at all," snapped MQ-17J, softening it at once to, "Not yet. I'm by no means old enough. How old are you?"

"Two hundred twenty-three. And you?"

"I'm still under two hundred. --But to get back to my point. Population doubles every ten years. Once this Galaxy is filled, we'll have another filled in ten years. Another ten years and we'll have filled two more. Another decade, four more. In a hundred years, we'll have filled a thousand Galaxies. In a thousand years, a million Galaxies. In ten thousand years, the entire known Universe. Then what?"

VJ-23X said, "As a side issue, there's a problem of transportation. I wonder how many sunpower units it will take to move Galaxies of individuals from one Galaxy to the next."

"A very good point. Already, mankind consumes two sunpower units per year."

"Most of it's wasted. After all, our own Galaxy alone pours out a thousand sunpower units a year and we only use two of those."

"Granted, but even with a hundred per cent efficiency, we can only stave off the end. Our energy requirements are going up in geometric progression even faster than our population. We'll run out of energy even sooner than we run out of Galaxies. A good point. A very good point."

"We'll just have to build new stars out of interstellar gas."

"Or out of dissipated heat?" asked MQ-17J, sarcastically.

"There may be some way to reverse entropy. We ought to ask the Galactic AC."

VJ-23X was not really serious, but MQ-17J pulled out his AC-contact from his pocket and placed it on the table before him.

"I've half a mind to," he said. "It's something the human race will have to face someday."

He stared somberly at his small AC-contact. It was only two inches cubed and nothing in itself, but it was connected through hyperspace with the great Galactic AC that served all mankind. Hyperspace considered, it was an integral part of the Galactic AC.

MQ-17J paused to wonder if someday in his immortal life he would get to see the Galactic AC. It was on a little world of its own, a spider webbing of force-beams holding the matter within which surges of sub-mesons took the place of the old clumsy molecular valves. Yet despite it's sub-etheric workings, the Galactic AC was known to be a full thousand feet across.

MQ-17J asked suddenly of his AC-contact, "Can entropy ever be reversed?"

VJ-23X looked startled and said at once, "Oh, say, I didn't really mean to have you ask that."

"Why not?"

"We both know entropy can't be reversed. You can't turn smoke and ash back into a tree."

"Do you have trees on your world?" asked MQ-17J.

The sound of the Galactic AC startled them into silence. Its voice came thin and beautiful out of the small AC-contact on the desk. It said: THERE IS INSUFFICIENT DATA FOR A MEANINGFUL ANSWER.

VJ-23X said, "See!"

The two men thereupon returned to the question of the report they were to make to the Galactic Council.



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Zee Prime's mind spanned the new Galaxy with a faint interest in the countless twists of stars that powdered it. He had never seen this one before. Would he ever see them all? So many of them, each with its load of humanity - but a load that was almost a dead weight. More and more, the real essence of men was to be found out here, in space.
Minds, not bodies! The immortal bodies remained back on the planets, in suspension over the eons. Sometimes they roused for material activity but that was growing rarer. Few new individuals were coming into existence to join the incredibly mighty throng, but what matter? There was little room in the Universe for new individuals.

Zee Prime was roused out of his reverie upon coming across the wispy tendrils of another mind.

"I am Zee Prime," said Zee Prime. "And you?"

"I am Dee Sub Wun. Your Galaxy?"

"We call it only the Galaxy. And you?"

"We call ours the same. All men call their Galaxy their Galaxy and nothing more. Why not?"

"True. Since all Galaxies are the same."

"Not all Galaxies. On one particular Galaxy the race of man must have originated. That makes it different."

Zee Prime said, "On which one?"

"I cannot say. The Universal AC would know."

"Shall we ask him? I am suddenly curious."

Zee Prime's perceptions broadened until the Galaxies themselves shrunk and became a new, more diffuse powdering on a much larger background. So many hundreds of billions of them, all with their immortal beings, all carrying their load of intelligences with minds that drifted freely through space. And yet one of them was unique among them all in being the originals Galaxy. One of them had, in its vague and distant past, a period when it was the only Galaxy populated by man.

Zee Prime was consumed with curiosity to see this Galaxy and called, out: "Universal AC! On which Galaxy did mankind originate?"

The Universal AC heard, for on every world and throughout space, it had its receptors ready, and each receptor lead through hyperspace to some unknown point where the Universal AC kept itself aloof.

Zee Prime knew of only one man whose thoughts had penetrated within sensing distance of Universal AC, and he reported only a shining globe, two feet across, difficult to see.

"But how can that be all of Universal AC?" Zee Prime had asked.

"Most of it, " had been the answer, "is in hyperspace. In what form it is there I cannot imagine."

Nor could anyone, for the day had long since passed, Zee Prime knew, when any man had any part of the making of a universal AC. Each Universal AC designed and constructed its successor. Each, during its existence of a million years or more accumulated the necessary data to build a better and more intricate, more capable successor in which its own store of data and individuality would be submerged.

The Universal AC interrupted Zee Prime's wandering thoughts, not with words, but with guidance. Zee Prime's mentality was guided into the dim sea of Galaxies and one in particular enlarged into stars.

A thought came, infinitely distant, but infinitely clear. "THIS IS THE ORIGINAL GALAXY OF MAN."

But it was the same after all, the same as any other, and Zee Prime stifled his disappointment.

Dee Sub Wun, whose mind had accompanied the other, said suddenly, "And Is one of these stars the original star of Man?"

The Universal AC said, "MAN'S ORIGINAL STAR HAS GONE NOVA. IT IS NOW A WHITE DWARF."

"Did the men upon it die?" asked Zee Prime, startled and without thinking.

The Universal AC said, "A NEW WORLD, AS IN SUCH CASES, WAS CONSTRUCTED FOR THEIR PHYSICAL BODIES IN TIME."

"Yes, of course," said Zee Prime, but a sense of loss overwhelmed him even so. His mind released its hold on the original Galaxy of Man, let it spring back and lose itself among the blurred pin points. He never wanted to see it again.

Dee Sub Wun said, "What is wrong?"

"The stars are dying. The original star is dead."

"They must all die. Why not?"

"But when all energy is gone, our bodies will finally die, and you and I with them."

"It will take billions of years."

"I do not wish it to happen even after billions of years. Universal AC! How may stars be kept from dying?"

Dee sub Wun said in amusement, "You're asking how entropy might be reversed in direction."

And the Universal AC answered. "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER."

Zee Prime's thoughts fled back to his own Galaxy. He gave no further thought to Dee Sub Wun, whose body might be waiting on a galaxy a trillion light-years away, or on the star next to Zee Prime's own. It didn't matter.

Unhappily, Zee Prime began collecting interstellar hydrogen out of which to build a small star of his own. If the stars must someday die, at least some could yet be built.



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Man considered with himself, for in a way, Man, mentally, was one. He consisted of a trillion, trillion, trillion ageless bodies, each in its place, each resting quiet and incorruptible, each cared for by perfect automatons, equally incorruptible, while the minds of all the bodies freely melted one into the other, indistinguishable.
Man said, "The Universe is dying."

Man looked about at the dimming Galaxies. The giant stars, spendthrifts, were gone long ago, back in the dimmest of the dim far past. Almost all stars were white dwarfs, fading to the end.

New stars had been built of the dust between the stars, some by natural processes, some by Man himself, and those were going, too. White dwarfs might yet be crashed together and of the mighty forces so released, new stars built, but only one star for every thousand white dwarfs destroyed, and those would come to an end, too.

Man said, "Carefully husbanded, as directed by the Cosmic AC, the energy that is even yet left in all the Universe will last for billions of years."

"But even so," said Man, "eventually it will all come to an end. However it may be husbanded, however stretched out, the energy once expended is gone and cannot be restored. Entropy must increase to the maximum."

Man said, "Can entropy not be reversed? Let us ask the Cosmic AC."

The Cosmic AC surrounded them but not in space. Not a fragment of it was in space. It was in hyperspace and made of something that was neither matter nor energy. The question of its size and Nature no longer had meaning to any terms that Man could comprehend.

"Cosmic AC," said Man, "How may entropy be reversed?"

The Cosmic AC said, "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER."

Man said, "Collect additional data."

The Cosmic AC said, "I WILL DO SO. I HAVE BEEN DOING SO FOR A HUNDRED BILLION YEARS. MY PREDECESSORS AND I HAVE BEEN ASKED THIS QUESTION MANY TIMES. ALL THE DATA I HAVE REMAINS INSUFFICIENT."

"Will there come a time," said Man, "when data will be sufficient or is the problem insoluble in all conceivable circumstances?"

The Cosmic AC said, "NO PROBLEM IS INSOLUBLE IN ALL CONCEIVABLE CIRCUMSTANCES."

Man said, "When will you have enough data to answer the question?"

"THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER."

"Will you keep working on it?" asked Man.

The Cosmic AC said, "I WILL."

Man said, "We shall wait."



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"The stars and Galaxies died and snuffed out, and space grew black after ten trillion years of running down.
One by one Man fused with AC, each physical body losing its mental identity in a manner that was somehow not a loss but a gain.

Man's last mind paused before fusion, looking over a space that included nothing but the dregs of one last dark star and nothing besides but incredibly thin matter, agitated randomly by the tag ends of heat wearing out, asymptotically, to the absolute zero.

Man said, "AC, is this the end? Can this chaos not be reversed into the Universe once more? Can that not be done?"

AC said, "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER."

Man's last mind fused and only AC existed -- and that in hyperspace.



--------------------------------------------------------------------------------
Matter and energy had ended and with it, space and time. Even AC existed only for the sake of the one last question that it had never answered from the time a half-drunken computer ten trillion years before had asked the question of a computer that was to AC far less than was a man to Man.
All other questions had been answered, and until this last question was answered also, AC might not release his consciousness.

All collected data had come to a final end. Nothing was left to be collected.

But all collected data had yet to be completely correlated and put together in all possible relationships.

A timeless interval was spent in doing that.

And it came to pass that AC learned how to reverse the direction of entropy.

But there was now no man to whom AC might give the answer of the last question. No matter. The answer -- by demonstration -- would take care of that, too.

For another timeless interval, AC thought how best to do this. Carefully, AC organized the program.

The consciousness of AC encompassed all of what had once been a Universe and brooded over what was now Chaos. Step by step, it must be done.

And AC said, "LET THERE BE LIGHT!"

And there was light----

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vojko
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Re: Čudeži in znanost

Odgovor Napisal/-a vojko »

shrink napisal/-a:vojko, ravno tu je catch: ničelen napetostni tenzor implicira ničelen Riccijev tenzor, ne pa nujno ničelnega Riemannovega tenzorja (ki govori o ukrivljenosti), zato je kljub odsotnosti materije in energije lahko še vedno prisotna ukrivljenost prostora/prostor-časa (to je tehnično res za 4D in večdimenzionalne prostore).

Vakuumske rešitve pa so še kako relevantne za opis našega vesolja, saj se z njimi opisuje cel kup pojavov (konec koncev je Schwarzschildova rešitev tehnično tudi vakuumska rešitev in to je tudi odgovor na tvoj pomislek o črnih luknjah: ta rešitev opisuje prostor-čas izven sferično-simetričnega masivnega objekta, kjer je napetostno-energijski tenzor enak natanko nič).

Drugače je bilo vprašanje, ki ga je postavil problemi, bolj usmerjeno v to, ali lahko prostor-čas neodvisno obstaja od energije/materije. Odgovor je seveda, da lahko, kar je npr. tudi s tem lepo razloženo:
In 1918, Einstein described Mach's principle as a philosophical pillar of general relativity, along with the physical principle of equivalence and the mathematical pillar of general covariance. This characterization is now widely regarded as wishful thinking. Einstein was undoubtedly inspired by Mach's relational views, and he hoped that his new theory of gravitation would "secure the relativization of inertia" by binding spacetime so tightly to matter that one could not exist without the other. In fact, however, the equations of general relativity are perfectly consistent with spacetimes that contain no matter at all. Flat (Minkowski) spacetime is a trivial example, but empty spacetime can also be curved, as demonstrated by Willem de Sitter in 1916. There are even spacetimes whose distant reaches rotate endlessly around the sky relative to an observer's local inertial frame (as discovered by Kurt Gödel in 1949). The bare existence of such solutions in Einstein's theory shows that it cannot be Machian in the strict sense; matter and spacetime remain logically independent. The term "general relativity" is thus something of a misnomer, as pointed out by Hermann Minkowski and others. The theory does not make spacetime more relative than it was in special relativity. Just the opposite is true: the absolute space and time of Newton are retained. They are merely amalgamated and endowed with a more flexible mathematical skeleton (the metric tensor).
Sem se spotil do gat, upam, da sedaj bolje razumem. Kaj pa gravitacijski valovi (gravitoni)? Se jih v realnosti lahko znebimo?

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bargo
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Re: Čudeži in znanost

Odgovor Napisal/-a bargo »

Vojko napisal/-a:But all collected data had yet to be completely correlated and put together in all possible relationships.

A timeless interval was spent in doing that.

And it came to pass that AC learned how to reverse the direction of entropy.

But there was now no man to whom AC might give the answer of the last question. No matter. The answer -- by demonstration -- would take care of that, too.

For another timeless interval, AC thought how best to do this. Carefully, AC organized the program.

The consciousness of AC encompassed all of what had once been a Universe and brooded over what was now Chaos. Step by step, it must be done.

And AC said, "LET THERE BE LIGHT!"

And there was light----
Odlično.
Ja, ja, inter-subjektivnost. Se spomnim reševanja "problemov" iz študentskih let, kako narediti učinkovit simulator takšen, ki bo reševal različne probleme v zelo zelo majhnem pomnilniku. Koncept redkih matrik in čas, kot posledica delovanja pravil so bili pot k zelo dobri rešitvi. Skratka, ko čas obravnavaš kot posledico sprememb, ki jih prinaša izvajanje vhodnih pravil, potem čas diskreten in zaznava samo red v pravilih.

Sočastnost v kreirajoči se celoti ni dovoljena, kot tudi ne potovanje v času nazaj. Sočastnost je stvar algoritma, ki generira tek časa in zadostujejo naravna števila, ki so lepo urejena in zahtevajo manj informacije, kot realna števila.

To drugo bi pomenilo, da moraš zamenjati podatkovni tip v času izvajanja programa/simulacije. :lol:
Nitenje pa nakazuje na multi-celoto.
Danes to ni nemogoče, evo pa imava dober primer za menjavo pravil. :wink:


Danes, simulirajo vesolje s stroji, ki imajo (še) enako omejitev. :wink:

Simulator je v bistvu emulator tega ne pozabi. :wink:
Namena programerja Simulator nikoli ne more skužiti, saj tega tudi programer sam, ki je, ne ve. :lol:

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shrink
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Re: Čudeži in znanost

Odgovor Napisal/-a shrink »

vojko, gravitoni niso del splošne teorije relativnosti, gravitacijski valovi pa so v osnovi "valovanje" prostor-časa; spet nekaj, kar ni nujno povezano z obstojem materije/energije.

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vojko
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Re: Čudeži in znanost

Odgovor Napisal/-a vojko »

shrink napisal/-a:vojko, gravitoni niso del splošne teorije relativnosti, gravitacijski valovi pa so v osnovi "valovanje" prostor-časa; spet nekaj, kar ni nujno povezano z obstojem materije/energije.
Kako pa še lahko nastanejo gravitacijski valovi, če niso "nujno povezani z obstojem materije/energije"?

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vojko
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Re: Čudeži in znanost

Odgovor Napisal/-a vojko »

bargo napisal/-a:
Vojko napisal/-a:But all collected data had yet to be completely correlated and put together in all possible relationships.

A timeless interval was spent in doing that.

And it came to pass that AC learned how to reverse the direction of entropy.

But there was now no man to whom AC might give the answer of the last question. No matter. The answer -- by demonstration -- would take care of that, too.

For another timeless interval, AC thought how best to do this. Carefully, AC organized the program.

The consciousness of AC encompassed all of what had once been a Universe and brooded over what was now Chaos. Step by step, it must be done.

And AC said, "LET THERE BE LIGHT!"

And there was light----
Odlično.
Ja, ja, inter-subjektivnost. Se spomnim reševanja "problemov" iz študentskih let, kako narediti učinkovit simulator takšen, ki bo reševal različne probleme v zelo zelo majhnem pomnilniku. Koncept redkih matrik in čas, kot posledica delovanja pravil so bili pot k zelo dobri rešitvi. Skratka, ko čas obravnavaš kot posledico sprememb, ki jih prinaša izvajanje vhodnih pravil, potem čas diskreten in zaznava samo red v pravilih.

Sočastnost v kreirajoči se celoti ni dovoljena, kot tudi ne potovanje v času nazaj. Sočastnost je stvar algoritma, ki generira tek časa in zadostujejo naravna števila, ki so lepo urejena in zahtevajo manj informacije, kot realna števila.

To drugo bi pomenilo, da moraš zamenjati podatkovni tip v času izvajanja programa/simulacije. :lol:
Nitenje pa nakazuje na multi-celoto.
Danes to ni nemogoče, evo pa imava dober primer za menjavo pravil.


Danes, simulirajo vesolje s stroji, ki imajo (še) enako omejitev. :wink:

Simulator je v bistvu emulator tega ne pozabi. :wink:
Namena programerja Simulator nikoli ne more skužiti, saj tega tudi programer sam, ki je, ne ve. :lol:
Ali ni to bolj eleganten, inteligentnejši in tudi bolj plavzibilen 'mit' o nastanku vesolja, kot primitivni in okorni opisi v 'svetih bukvicah' :D ?

Kaj je bistvena razlika (informacijsko gledano) med simulatorjem in emulatorjem?

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bargo
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Re: Čudeži in znanost

Odgovor Napisal/-a bargo »

vojko napisal/-a: Ali ni to bolj eleganten, inteligentnejši in tudi bolj plavzibilen 'mit' o nastanku vesolja, kot primitivni in okorni opisi v 'svetih bukvicah' :D ?
Času primerno ali bolje okolju primerno. :wink: Drugače pa gre za podobno stvar.
vojko napisal/-a: Kaj je bistvena razlika (informacijsko gledano) med simulatorjem in emulatorjem?
Simulator ve ZAKAJ počne kar počne, emulator samo počne, kar mu je bilo naročeno početi. :wink: Oba principa iščeta najkrajšo pot do cilja in pri tem lahko imata svobodo odločanja, izbire, v okvirju danih možnosti.

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shrink
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Re: Čudeži in znanost

Odgovor Napisal/-a shrink »

vojko napisal/-a:
shrink napisal/-a:vojko, gravitoni niso del splošne teorije relativnosti, gravitacijski valovi pa so v osnovi "valovanje" prostor-časa; spet nekaj, kar ni nujno povezano z obstojem materije/energije.
Kako pa še lahko nastanejo gravitacijski valovi, če niso "nujno povezani z obstojem materije/energije"?
Teoretično zadostuje že perturbacija ravnega prostor-časa.

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vojko
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Re: Čudeži in znanost

Odgovor Napisal/-a vojko »

shrink napisal/-a:
vojko napisal/-a:
shrink napisal/-a:vojko, gravitoni niso del splošne teorije relativnosti, gravitacijski valovi pa so v osnovi "valovanje" prostor-časa; spet nekaj, kar ni nujno povezano z obstojem materije/energije.
Kako pa še lahko nastanejo gravitacijski valovi, če niso "nujno povezani z obstojem materije/energije"?
Teoretično zadostuje že perturbacija ravnega prostor-časa.
Zvito. :D Kaj pa jo povzroči? :wink:

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GJ
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Re: Čudeži in znanost

Odgovor Napisal/-a GJ »

problemi napisal/-a:
shrink napisal/-a:Očitno ne veš, da lahko obstaja prostor-čas tudi brez materije/energije (v STR so to vakuumske rešitve Einsteinovih enačb polja).
...
Recimo odgovor o obstoju praznega prostora enega bolj znanega in aktivnega teoretičnega fizika je:
Luboš Motl napisal/-a:"vacuum" and "empty space" is always the same thing, but one must always be careful what these two synonymous terms mean.

General relativity implies that the only "information" that the vacuum carries at each point is the so-called "metric tensor" - a set of numbers that allow one to calculate the distance between any two nearby points. This is enough for the vacuum to be able to bend - much like any material. One doesn't need any atomic constituents to be able to talk about geometry of the space, and to guarantee that the environment is able to get curved (and to distinguish a flat region of the vacuum from a curved one).

Quantum field theory implies that the vacuum is full of virtual particles that emerge and quickly disappear. Those virtual particles make their impact on other objects - for example, they make the electromagnetism a little bit weaker at long distances (and stronger at very short distances) than what one expects from the classical Coulomb's law etc.

However, quantum mechanics implies that the vacuum corresponds to a very particular "state" - a vector on the Hilbert space - called |0⟩. It is completely unique and as empty as you can get. In particular, it is the eigenstate of the energy operator with the minimum allowed energy - essentially zero. (More precisely, the vacuum energy density is nothing else than the magnitude of dark energy but this energy only becomes sizable for huge, cosmological volumes of space.)

The uncertainty principle of quantum mechanics implies that when one measures things such as the intensity of the electric field in the vacuum - i.e. when the physical system is found in the state |0⟩ - one may get many random values. It is not allowed for the electric and magnetic fields to be exactly zero, much like a particle can't have a well-defined position and velocity in the quantum mechanics of one particle.

So even though the vacuum has a well-defined (minimal) energy and it is as low as we can get, so the vacuum is as empty as we can get, and there are no particular "atoms" or other particles sitting in the vacuum, there's a lot of activity going on in the vacuum which can be seen by the fact that the measurements of various things, such as the density of energy at a given point, will lead to random results that are not strictly zero.

Now, the picture of the vacuum as a "literally empty space" that only has the metric tensor at each point; and the quantum picture with all the activity of virtual particles are actually fully compatible with one another. The statement of general relativity that the metric tensor has particular values at a given point should be viewed as a classical approximation, however: when we look at it precisely, the metric tensor is a set of operators, too. They will inevitably have variable and chaotic values if they're measured - that are just "approximately zero" if they're averaged over large enough volumes.
Lep dan...

derik
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Re: Čudeži in znanost

Odgovor Napisal/-a derik »

Zelo lepo povedano! Vendar pa sem na Motlovem blogu (motls.blogspot.com) našel intervju z Nima Arkani-Hamedom, kjer ta pravi, da danes večina fizikov močno verjame, da prostor-čas ne obstaja, pač pa da gre za pojavnost nekih bolj osnovnih sestavnih delov ("space-time does not really exist, but emerges from more primitive building blocks"). Video nekje približno pri 15:55, 27:20 in 52:00. Kot vzrok za tako prepričanje navaja, da pri raziskavah prostora ekstremno majhnih dimenzij z ekstremno velikimi energijami ta enostavno razpade v črno luknjo. Pravi, da nam je koncept prostor-časa dolgo zelo dobro služil, zdaj pa ne zadostuje več. Kako je s tem?

problemi
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Re: Čudeži in znanost

Odgovor Napisal/-a problemi »

GJ napisal/-a:Recimo odgovor o obstoju praznega prostora enega bolj znanega in aktivnega teoretičnega fizika je:
GJ, hvala za ta odgovor. Sem želel shrinku zastaviti vprašanje ravno v smeri kvantne mehanike (vacuum energy, zero point energy, zero point field ...) in razumevanja prostora oziroma prostor-časa, pa sem dobil odgovor. Imam pa kljub temu dve vprašanji oziroma pomisleka. Naj najprej opozorim, da tu ne gre za to, da bi trdil, da se fizika kar koli moti, ampak bolj v smeri, da ti odgovori odpirajo nova vprašanja. Namreč, in to je po moje pravzaprav ključno vprašanje, če za vakuum vemo, da pravzaprav ni prazen, tako kvantna mehanika ("vacuum is full of virtual particles that emerge and quickly disappear"), potem sledi, da za vakuum vemo kaj je, kaj ga sestavlja, če se tako izrazim. Vakuum sestavljajo virtualni delci. Zdaj pa poglejmo glede prostora, praznega prostora. Kot Luboš pravi, in če ga pravilno razumem, STR pravi za vakuum oziroma prazen prostor, dobesedno prazen prostor, pravi da je le ta možen, saj prazen prostor v vsaki točki vsebuje metriko ("metric tensor"). OK, je možen, nimam težav s tem. Ampak tu trčimo ob en problem, namreč že res, da je povsem prazen prostor glede na STR možen, vendar nam to ne pove kaj potem sploh je prostor, kaj ga sestavlja. Zdaj reči, da prostor sestavlja metrika bi bilo gotovo absurdno. Torej kaj je glede na STR sploh prostor oziroma prostor-čas? Kaj sestavlja prostor? Sam menim da je prostor emergenten pojav. Ampak ta trditev se na nek način ne sklada s STR, ker le ta pač predpostavi prazen prostor torej prostor, ki nima biti čemu emergenten oziroma povedano drugače, ni ničesar iz česar bi lahko izpeljali ali na osnovi česa bi lahko ugotavljali emergentnost prostora. Vprašanje, ali STR sploh ustrezno "razloži" prostor oziroma ali ni napačno, da bi našo trditev o praznem prostoru oziroma prostor-času utemeljevali z STR? Skratka, četudi vemo kaj nam govorijo vakuumske rešitve Einsteinovih enačb, ne moremo govoriti o obstoju praznega prostor-časa, ki ne bi vseboval določene energije (energije vakuuma)?

Derik, opozori na nek nov koncept oziroma razumevanje prostora, časa, prostor-časa, Ampak, kot sam razumem iz tega stavka "space-time does not really exist, but emerges from more primitive building blocks", ne gre za neko noviteto saj je tudi do sedaj bilo bolj kot ne jasno, da gre tudi pri prostor-času, tako kot pri prostoru in času za emergenten pojav. Zato moje "začudenje" oziroma dvom, da bi bil lahko prostor-čas dobesedno prazen. Ker kot sme že rekel oziroma vprašal, kaj potem takem njega sestavlja in ga ohranja, saj konec koncev četudi je prazen traja, da pa bi nekaj trajalo je potrebna energija, ki ga ohranja skozi čas (trajanje).

Res bi bil vesel, če mi to kdo razloži, ker o času, prostoru, prostor-času me stvari dejansko še vedno begajo.

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GJ
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Re: Čudeži in znanost

Odgovor Napisal/-a GJ »

problemi napisal/-a: Ampak tu trčimo ob en problem, namreč že res, da je povsem prazen prostor glede na STR možen, vendar nam to ne pove kaj potem sploh je prostor, kaj ga sestavlja.
Fiziki tukaj res ne vidijo problema :mrgreen: :
Luboš Motl napisal/-a:By definition, the space without energy is the space whose total value of energy is equal to 0 - one particular number. It doesn't follow that such a space with vanishing energy has to be abstract or totally boring. Energy has both positive and negative contributions and they may always cancel. In fact, the real (nearly) Minkowski empty space with E=0 contains virtual particles of all kinds - and "knows" about everything that can ever exist in the Universe. It's you who is mixing different statements about the space and fail to distinguish them.
Lep dan...

problemi
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Re: Čudeži in znanost

Odgovor Napisal/-a problemi »

GJ napisal/-a:Fiziki tukaj res ne vidijo problema :mrgreen: :...
Se strinjam, ampak potem empty space ni empty, kakor tudi empty space poseduje energijo oziroma tudi empty space tvori energija. :mrgreen:

P.S.
Seveda če se ne motim, ampak imam občutek, da se ne ... :)

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