P. Ulmschneider, Intelligent Life in the Universe, Adv. Astrobiol. Biogeophys. John Ball () and Carl Sagan (), it explains the lack of contact with .. aracer.mobi Wilde, S.A. . PDF | The radio and optical SETI programmes have yet to pick up a definite intelligent Intelligent life on Earth occu- The late Carl Sagan referred to our. PDF | We analize the cooperation betwen Joseph Shklovsky and Carl Sagan for the publication of the seminal book ”Intelligent Life in the.
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Collaboration between famous American Carl Sagan and world/famous Russian Müslüm Yıldız Just type "Intelligent Life in the Universe pdf" in Google search. gation for the Seattle Power Squadron. Is anybody out there? INTELLIGENT LIFE IN THE UNI-. VERSE. By I. S. Shklovskii, Carl. Sagan. Russian portion trans, by. Is intelligent life exceptional or abundant in the Universe? ▻ Arthur C. Clarke . It was designed by Carl Sagan, who shows it here. Piet van der.
So, life is favored in large-mass galaxies, and we could take MMW as a fiducial value. Stars can be constrained by type, since continually habitable zones i.
Of these, we must include only the fraction bearing planetary systems. Current searches for exoplanets indicate that this fraction can be substantial.
Perhaps surprisingly, even binary star systems may contribute. I will leave the notion of a galactic habitable zone aside. Once there are high metallicity stars and planetary disks sprinkled with the chemical elements needed for life the Chemical Age can begin. Indeed, it is likely that life on Earth took advantage of both local synthesis and delivery.
Apart from water, other simple molecules are also supposed to be present, although the specifics may differ CH4 , CO2 , NH As indicated by Miller-type experiments , to produce amino acids in situ there is also a need for a reducing atmosphere.
Planetary platforms with volcanism have a clear advantage . Taking the age of the Earth to be 4. For example, Davies and Lineweaver conjectured that there may have been several early life experiments, which were reset by intense environmental disturbances .
Given that such considerations somewhat blur the line between the chemical and biological ages, we adopt a working hypothesis that the chemical age is characterized by the prebiotic chemical processes that led to the first successful life experiment, irrespective as to when it happened. Clearly, by 3. Thus, the fundamental open question that lies at the boundary of the two ages is precisely the transition form nonliving to living matter, or abiogenesis. If we adopt the working and necessarily oversimplistic definition of life as a self-sustaining network of chemical reactions capable of exchanging energy with the environment and of Darwinian reproduction, prebiotic chemistry addresses the emergence of such a network of reactions.
Life is a very complex manifestation of this urge, an imbalance that recreates itself : it is not matter, but a process that happens to matter. Although the uniformity of life on Earth suggests that all extant organisms descended from a last universal common ancestor LUCA , we know little of the abiotic ingredients and prebiotic chemistries present on the primitive Earth from which the LUCA evolved . Coupled to the question of abiogenesis is the origin of homochirality, or why biomolecules display a near perfect spatial asymmetry [42, 43].
These fatty droplets, according to Oparin, would have made a nice protective environment allowing molecules accidentally trapped in their interior to react with each other with reduced external interference [34, 35]. Occasionally, certain reactions would produce more chemicals and grow in complexity. As opposed to reproduction in a more organized genetic framework, reproduction here would initially happen at random, as turbulent external conditions would force some droplets to split.
Shaking salad dressing shows this. In rare cases, the daughters would contain the right chemicals to also maintain self-sustaining reactions and a population of somewhat similar protocells would start to develop. Doron Lancet and collaborators at the Weitzman Institute have developed computer simulations of such lipid world scenarios, showing that when a parent cell can produce more than one self-catalyzing daughter a chain reaction may occur, leading to a kind of primitive life .
We should expect that protocells containing molecules that reproduced more efficiently and that could better extract and metabolize energy from the outside environment had an advantage over others and slowly came to dominate the population .
The countering position is that genetics came first: duplication preceded metabolism. Unlike DNA, it can function as an enzyme, so it is able to catalyze its own polymerization that is, the chaining of smaller pieces into longer molecules like pearls in a necklace and duplication. If we assume, quite reasonably, that life started simple, a self-sufficient replicator is one way to go. As Tom Fenchel remarked in Origin and Early Evolution of Life , the real advantage of the RNA-first scenario is that it allows for extensive laboratory-based studies.
After eons of trial and error, a symbiotic fusion of the two eventually developed, creating a cell with optimized replication capability. In any case, this discussion illuminates the point made learner that the boundaries between the chemical and biological ages are quite blurry.
We may thus assume that, at some point between 3.
Of course, it may have started eons before in another planetary platform in this or other galaxy. In any case, the transition from nonliving to living matter would have happen there as well—unless life was delivered ready-made from space. However, even if one accepts the panspermia hypothesis [50, 51] this author, in particular, finds it quite far-fetched , abiogenesis had to happen at least once in the universe.
The simplest autonomous living entity is a cell. There is, of course, an enormous and ill-understood jump in complexity from coacervates with some kind of duplicating software to the simplest cells known to us, prokaryotes. Blue-green algae and many bacteria are prokaryotes, primitive cells where DNA is bundled into a coil without a membrane separating it from the rest of the cell.
In eukaryotes, the more sophisticated cells like the ones in our body, an isolated nucleus houses the genetic material. As we look into the history of life on Earth, we discover that single-celled organisms were by far its most enduring inhabitants.
The numbers are remarkable: from around 3. That is, for roughly 2. Eukaryotes appeared close to the end of this period, thanks to collective efforts of the photosynthetic blue-green algae, when oxygen became more abundant in the atmosphere. This fact should give us pause. The stars are the prokaryotes. The crucial transition from single-celled to multi-celled organisms, from our amoeba-like ancestors to sponges, happened for a number of improbable factors: most importantly, the increase in atmospheric oxygen between 2.
A consequence of this increase is the parallel production of ozone due to the action of UV sunlight on oxygen. This ozone created a protective layer between organisms and the same nasty UV radiation from the Sun, allowing more complex life forms to evolve.
When we consider the possibility of life elsewhere in the cosmos these factors and many more are crucial. If life forms are well-adapted to the environment, that is, if there is little or no environmental pressure, mutations will hardly be beneficial. Thus, different environmental pressure will lead to different demands on adaptability and hence on the phenotype of successful life forms .
From the perspective of astrobiology, both the study of life on Earth from its origins to present-day extremophiles  and the possibility of detecting the signature of life in exoplanets  have been the focus of much activity and the basis for the planning of future exploratory missions and telescopic design .
See, e. Although it can be argued that bonobos, chimpanzees, dolphins and other mammals display a high level of self-awareness, emotional depth, and crude tool manipulation, I am defining the dawn of the cognitive age to coincide with the dawn of the first modern humans, the only species we know of capable of creating complex 5 technology based on the assembly of different materials and of creating art, that is, the only species that has both functionality and aesthetic considerations during the act of creation extending beyond mere survival needs.
Given the plurality of worlds and the abundance of organic chemicals in the interstellar and circumstellar medium for example, the recently-found polycyclic aromatic hydrocarbons  , added to the remarkable resilience of terrestrial extremophiles, it is hard to support the idea that life has only found its way on our planet.
On the other hand, when thinking about life in the universe one must distinguish between simple, one-celled life and complex, multicellular life. And even here, we must be careful to distinguish between multicellular and intelligent life. Taking Earth as our only illustration thus far, life was single-celled for about 3 billion out of 3. Intelligence, very broadly defined as the ability to fashion tools for a definite purpose, only for the past million years or so with Homo Abilis, although more complex tool making, the interest and ability to bury the dead, and the advent of art— three characteristics of the cognitive age— probably came only much more recently.
However, we must still wonder whether intelligence is a reproducible feature of life, that is, whether life elsewhere can be intelligent, capable of art and technology.
And, if so, whether it is widespread in the cosmos. In their courageous Rare Earth: Why Complex Life Is Uncommon in the Universe, Peter Ward and Donald Brownlee argued very convincingly that life may not be uncommon in the Universe but it likely exists elsewhere only in its simplest form: alien Earth-like planets may support alien microorganisms but not much more than that .
Complex, multicellular life relies on too many planetary factors—even after clearing all the chemical roadblocks—to be common. For example, a large moon to stabilize the planetary axis tilt and hence the seasons, a magnetic field to shield off radiation, plate tectonics to remix surface and ocean chemistry that helps regulate CO2 levels, etc. Since it is difficult to imagine how intelligence—here or anywhere else—could have emerged without millions of years of evolving multicellular creatures, the discovery of multicellular aliens would be a great boost to the possibility that there are other smart creatures out there.
Even so, it is important to keep in mind that human intelligence appeared as a by-product of random cosmic and evolutionary accidents: intelligence is not the end-goal of evolution, as one hundred and fifty million years of dinosaurs demonstrate .
If we take the possibility of alien intelligent life seriously, we must ponder a few questions. If we imagine that life evolved in another stellar system even as little as a few million years earlier than it did here, and that it reached a stage in its evolution where complex creatures became intelligent, then it follows that some of these aliens would have had plenty of time to reach amazingly advanced levels of technological sophistication.
Considering what we have achieved with only four hundred years of modern science, their technology would be like magic to us. If, like humans, they suffer from wanderlust, they would have had the means and plenty of time to explore the galaxy many times over.
Traveling at 0. So, where is everybody? Fifty possible resolutions, some amusing and others quite serious, can be found in Ref. Floating away, carried on the waves again, he saw that his shell had been wrapped up in some sort of plant fiber, and was cradled by a soft square of a similar fiber. He sniffed. More accurately, Noa had made him a nest. He smelled her all over it.
Ever so gently, he flexed his claws. It was a nice nest, he could tell that, despite his pain. It was almost as soft as the one made by Third of ptery scales and her belly fluff. The fire was a nice touch; bigger than he would ever light on a cold night, but he supposed that the nearly naked Newcomers might need more to ward off the chill.
And now that he studied it, he realized it was well contained. In spite of himself, he felt sympathy for her. How difficult would it be to raise a litter with only two adults?
How would Third ever have managed without First and Second to hunt and protect her, Hsissh, Shissh, and their brothers and sisters? There was no swell of poison. He hunched into the nest, feeling violated. You have to be gentle, Noa. Whatever for? But of course, the Newcomers were wave-ignorant—like Third had been at the end. A male of the species, also tan skin with dark brown hair, who smelled like Noa, but not like Mom. Perhaps the other parent?
The round metal plate in the side of her skull glinted dully in the light. At the center of it was an opening … and then darkness. Hsissh could smell no blood, bone, or other gore from the gaping hole. These creatures die in cages; it would be wrong to keep him. They probably need to be with their own kind to remain healthy. He could go months without contact with his kind. But it was a well-considered hypothesis.
Another smaller, though still enormous, Newcomer came over and gazed down at Hsissh. He smelled like Noa, Mom, and Dad—a blood kin. His skin was tan, with dark brown fur on top of his head, like Mom and Dad, and his eyes were light in color. He idly played with the metal disk in the side of his head with the long, slender appendage of a paw. In point of fact the werfles had males, females, and females that had matured to Thirds, nursing adults who passed on genetic information through their milk.
The Newcomers had curiously ineffectual claws; they were short, stubby, and thin. However, Hsissh was discovering they were perfect for grooming without the worry of shedding blood. Or maybe it was the color of her skin. It was the same rich brown as the bark of a healthy red nut tree, and twice as smooth. It was against the rules of The One to communicate with the Newcomers, lest they know they were being scrutinized. Like sub-atomic particles whose behavior changed when observed, research subjects behaved differently when they knew they were being watched.
But suddenly he wanted her to know. He concentrated and tugged at the waves that coursed between Noa, Kenji, and himself. Hsissh squeaked in joy and wonder. The Newcomers were truly an intelligent species! She nodded.
His stomach was filled with fresh rat, and his mouth was still flavored with its blood. Exalting in the feeling of all being right with the world, he rolled onto his back … and all was not right anymore. The attic was made of wood slats that were hard and had splinters that poked through his fur.
Rolling back over, he scanned the room. The box was filled with faux fur humans used for colder temperatures. Rats enjoyed nesting in it; perhaps he would, too? Trundling over, he slid inside, kneaded the soft material with his claws, and curled into a ball.
It was very comfortable and, as a plus, smelled like his favorite prey. He closed his eyes. Rain was pattering on the roof and the single attic window. A loud clacking almost woke him.
And then he realized the clacking was coming from the wave. It was Shissh, snapping two pincers at the front of her carapace, sending her consciousness to interrupt his nap and heckle him for not slipping out of his body.
He almost woke up just to spite her; but seeing her, even in this new form, caused his body to release a flood of bonding hormones. He purred with familial love. Did she still feel the bond in that hard, cold shell? Did she still think of Third—the only member of their three parents whose werfle body had been inhabited by The One? Shissh spoke into his mind. He never should have told her that name. Go away and let me sleep. Shissh clicked her pincers and waved her eye stalks.
Hsissh sent his thoughts into The Gathering before Shissh had finished. It was held in a cavern with an opening directly above that let in the sparkle of the stars—but not the glow of the time gate or human satellites. The cavern had been destroyed thousands of cycles ago, and this was only the memory of a memory that The One all shared.
It was crowded with dream versions of The One. Most were in the form of werfles, but there were exotic creatures from several dozen worlds scattered among them. It was Misch.
Introduce the Fourth Plague before it happens here! He had seen orphaned human children too weak to defend themselves from rats feasting on their flesh. Hopping up and down with the excitement of his own recent epiphany, Hsissh explained. Every human with the metal implant has nanos—tiny machines—in their brains. They are awakened in later adolescence. Hsissh rushed on. They know that all matter is made of waves. Nor were the creatures we eradicated at the end of the last Epoch. There was a collective silence from The One.
And then a thought, so soft he almost missed it, entered his consciousness. Ish stood on his back four hind limbs and waved his paws. Misch swished his tail. The ones here were seeking enlightenment and to escape the material, non-wave focused cultures of Earth. Ish clasped his top two claw pairs behind his back and strode through the Gathering Place on his back four legs. His middle pair of paws waved.
That is the waves from which all matter is derived, obviously. The universe is predator and prey. At last, the tide began to subside, and a chorus rose in the cavern. The One were of one mind after the chorus … One hundred cycles around the sun … certainly in that time humans would evolve to feel waves, if they were already on the verge?
One by one, all the consciousnesses began slipping away into other dreams, and Hsissh found himself alone with Ish, Misch, and Shissh. They are debauched and lazy.
Ish turned to Hsissh. Only Hsissh and his luminescent, crustacean once-kin were left. He felt a lump in his stomach; at the same time, he felt a warmth in his hearts. Shissh had chosen the crustacean form because it was not social, and did not mourn the departure of others of its kind. Still, because she had stayed, Hsissh felt that she must still care about him.
Whenever they had a species that became too problematic, it was easy enough to cull or eradicate them with a specially mutated pathogen. Shissh had told him this much before. Since the species I inhabit does not travel, I think there may have been other wave riding species that have brought their stories with them.
She dreamed aloud of traveling to distant moons when she snuggled with Hsissh at night … He looked through the opening in the ceiling. It was close to her bedtime now. He found himself shivering despite the faux furs and bolted from the box. Shissh was right, he was too attached to Noa and her family. He had originally stayed for the rats in the attic, the beds, and out of curiosity; but he liked them, and they would die.
Instead of darting down the trapdoor that led to the hallway, he skittered over to the window. The latch gave, the window opened, and he slithered out into the rainy night. Sliding down the slope of the roof, he swung over the edge and jumped into the ivy that grew up the side of the house.
He was halfway down when he heard a creak of a window opening. He slunk into the low, alien vegetation around the home that was lit by electric spotlights. Bowing his head, Hsissh wove through the plants toward the forest beyond.
He increased his speed. The bipedal steps hesitated. The cold mud beneath him seemed to wrap around his claws and hold him immobilized. An enormous drop of frigid water fell from a tree and landed squarely on his nose.
Hsissh turned around and slid through the underbrush.
She should have gone home, but instead she was crying his name. Noa was trying to save him—again. It was foolish. She could suffer hypothermia, or get lost and injured. He crawled out of the undergrowth. Scooping him up, she touched her nose to his.
Instead, she went through the front door, into the foyer, and then into the front room where her parents were reading. Teeth still clacking, she carried Hsissh back to her room and set him down on her bed. As she slipped into dry pajamas, Hsissh made a show of prowling under the covers for rats.
Her body was still trembling, and she pulled him close. Hsissh curled himself into a ball. Her body was around his, much like how Third had coiled around Hsissh and Shissh as hatchlings and then kits. Noa was prone to misadventures, and Hsissh could see that begging her to be safe was like screaming into the void.
It made him think of being with Third after her mind had been stripped by the wasting disease. Hsissh had begged her to slip into the wave, to stay with him. He kept pleading even after all hope was lost. He should have checked on her more frequently, in the waves and in the flesh. In the end, he found himself wishing for just a few more breaths of time to be with her, even just to have her nuzzle him in her wave-ignorant, mind-degenerated state. For a moment, they were airborne, and Hsissh braced his achy muscles for the inevitable reunion with the ground.
She stroked his sore back with warm, gentle hands, and he gingerly curled into a ball. His old rib injury hurt, and this body was getting old, period. Kenji was quiet, his eyes focused on the window. Read it in the late 70s, in the original hardcover edition from apparently not even listed here at Goodreads , as background while preparing a review of Carl Sagan's popular-science book, Broca's Brain.
This collaboration with Soviet astrophysicist Iosif Shklovsky, which was a revised, extended, and retitled version of a book Shklovsky had published in , struck me when I read it—and still does—as scientifically much more serious and focused than what I was reviewing. And yet I can Read it in the late 70s, in the original hardcover edition from apparently not even listed here at Goodreads , as background while preparing a review of Carl Sagan's popular-science book, Broca's Brain.
And yet I can see now a similarity: Among other subjects, Broca's Brain presented some of what Sagan had managed to glean from a field not his own, neuroscience, and from there ventured upon some guesses. Though it had its virtues, the book also advanced a romanticized view of the nature of scientific work.
Likewise, Intelligent Life in the Universe first broadly surveyed much of what was known about biology, astrophysics, et al. As its title reveals, smart aliens were among the possibilities.
In science, which is never complete, somebody somewhere must always speculate. Some parts of the book's survey of astrophysics remain with me still: Mostly lost in the mists are its thoughts about life elsewhere in the universe. My middling rating therefore is based mainly on not remembering the book in much detail. Some reviewers here have called the book dated. In science, work done yesterday may be dated today. What matters is whether it was in any way fruitful or useful.
Wikipedia's entry on Shklovsky assesses Intelligent Life in the Universe as "the first comprehensive discussion of this field" without attributing it which such entries aren't supposed to do. My guess is that the book occupies a particular place—though I can't say exactly what it is—in the history of what we now call exobiology. In a recent glance through the endnotes of an upcoming book on the subject, Five Billion Years of Solitude: The Search for Life Among the Stars , I noticed a reference to this work, so I'm not the only one to see it as old but not forgotten.
View 2 comments. This book was a good friend for a long time. Sep 25, Ushan rated it liked it Shelves: The first part of this book is a popular introduction to astronomy and cosmology; as far as I can tell, it is accurate but dated: Also, a lot of what we know about the Solar system was found by robot explorers such as the Voyagers, which then just began to fly. The book speculates that dinosaurs became extinct at the end of t The first part of this book is a popular introduction to astronomy and cosmology; as far as I can tell, it is accurate but dated: The book speculates that dinosaurs became extinct at the end of the Cretaceous period because a nearby supernova explosion bathed Earth in mutagenic radiation; nowadays it is thought that it was an asteroid impact.
The second part briefly defines life and speculates on its origin; for a more modern and interesting treatment, see Life's Solution by Simon Conway Morris, though take it with a grain of salt because the author is a creationist.
It then speculates on life in the Solar system with a particular emphasis on Mars, life on Earth as seen by hypothetical Martian astronomers, and life in other solar systems. It discusses vision in alien animals without mentioning echolocation, a perfectly good substitute used by Earth bats and whales. The third part discusses radio and laser contact with extraterrestrial civilizations, and speculates on whether the satellites of Mars are of artificial origin; we now know that they aren't: It's a little bit more complicated than the average book for beginners, so I wouldn't recommend it as a starting book for Astronomy, but the concepts are easy to understand by any common person like me with no degree who [I can't find the english version of this on Goodreads the title is "The Universe".
It's a little bit more complicated than the average book for beginners, so I wouldn't recommend it as a starting book for Astronomy, but the concepts are easy to understand by any common person like me with no degree who has just read a bunch of stuff about the subject. Jun 25, Elisabeth rated it liked it Shelves: Well written, highly readable, but far too dated to be useful or even terribly interesting.
It must have been fascinating in the late 60s, but I was left wondering how much of what they said has turned out in the long run to be even close to true. Some of the description of methodology has been interesting, though. View 1 comment. Jul 31, Joy added it. Aug 02, Thomas rated it really liked it Shelves: A little dense for the casual reader.
But a really wonderful resource nonetheless. Apr 14, Jay is currently reading it. The best book on the subject. It covers a lot of ground in fine style. Feb 24, Noel marked it as to-read.
Jan 06, Terry rated it it was amazing. Delighted and dazzled me when I read this in high school late 60's. Out of date now. Fun for a stubborn 8th grade geek. Oct 03, Daniel Clark rated it it was amazing.
I thought this book was important, and interesting to me. David Massey rated it liked it Nov 09, Avi Smila rated it it was amazing Mar 28,