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Bulgaroctonus
15 Jan 06,, 03:23
This is a good book review from the New York Times . It reviews the The Cosmic Landscape by Leonard Susskind, a theoretical physics professor at Stanford University who is widely considered to be one of the most entertaining mavericks in the field of string theory.

Susskind addresses the scientific version of intelligent design known as the Anthropic Principle.

http://www.nytimes.com/2006/01/15/books/review/15powell.html


January 15, 2006
'The Cosmic Landscape,' by Leonard Susskind
Across the Megaverse
Review by COREY S. POWELL

Physicists are not like ordinary people, and string theorists are not like ordinary physicists. Even compared with their peers, crafters of the arcane model of reality that is string theory think in terms of sweeping explanations of nature's design. Leonard Susskind, a founder of the theory and one of its leading practitioners, brazenly lays out this no-boundaries attitude on the first page of his new book. His research, he declares, "touches not only on current paradigm shifts in physics and cosmology, but also on the profound cultural questions that are rocking our social and political landscape: can science explain the extraordinary fact that the universe appears to be uncannily, nay, spectacularly, well designed for our own existence?"

What troubles Susskind is an intelligent design argument considerably more vexing than the anti-evolution grumblings recently on trial in Dover, Pa. Biologists can point to unambiguous evidence that evolution truly does happen and that it can account for many otherwise inexplicable aspects of how organisms function. For those who take a more cosmic perspective, however, the appearance of design is not so simply refuted. If gravity were slightly stronger than it is, for instance, stars would burn out quickly and collapse into black holes; if gravity were a touch weaker, stars would never have formed in the first place. The same holds true for pretty much every fundamental property of the forces and particles that make up the universe. Change any one of them and life would not be possible. To the creationist, this cosmic comity is evidence of the glory of God. To the scientist, it is an embarrassing reminder of our ignorance about the origin of physical law.

Until recently, most physicists took it on faith that as they refined their theories and upgraded their experiments they would eventually expose a set of underlying rules requiring the universe to be this way and this way only. In "A Brief History of Time," Stephen Hawking recalled Albert Einstein's question "How much choice did God have in constructing the universe?" before replying that, judging from the latest ideas in physics, God "had no freedom at all." Like many leading physicists at the time, Hawking believed that scientists were closing in on nature's essential rules - the ones that even God must obey - and that string theory was leading them on a likely path to enlightenment.

Although string theory resists translation into ordinary language, its central conceit boils down to this: All the different particles and forces in the universe are composed of wriggling strands of energy whose properties depend solely on the mode of their vibration. Understand the properties of those strands, the thinking once went, and you will understand why the universe is the way it is. Recent work, most notably by Joseph Polchinski of the University of California, Santa Barbara, has dashed that hope. The latest version of string theory (now rechristened M-theory for reasons that even the founder of M-theory cannot explain) does not yield a single model of physics. Rather, it yields a gargantuan number of models: about 10500, give or take a few trillion.

Not one to despair over lemons, Susskind finds lemonade in that insane-sounding result. He proposes that those 10500 possibilities represent not a flaw in string theory but a profound insight into the nature of reality. Each potential model, he suggests, corresponds to an actual place - another universe as real as our own. In the spirit of kooky science and good science fiction, he coins new names to go with these new possibilities. He calls the enormous range of environments governed by all the possible laws of physics the "Landscape." The near-infinite collection of pocket universes described by those various laws becomes the "megaverse."

Susskind eagerly embraces the megaverse interpretation because it offers a way to blow right through the intelligent design challenge. If every type of universe exists, there is no need to invoke God (or an unknown master theory of physics) to explain why one of them ended up like ours. Furthermore, it is inevitable that we would find ourselves in a universe well suited to life, since life can arise only in those types of universes. This circular-sounding argument - that the universe we inhabit is fine-tuned for human biology because otherwise we would not be here to see it - is known as the Anthropic Principle and is reviled by many cosmologists as a piece of vacuous sophistry. But if ours is just one of a near-infinite variety of universes, the Anthropic Principle starts to sound more reasonable, akin to saying that we find ourselves on Earth rather than on Jupiter because Earth has the mild temperatures and liquid water needed for our kind of life.

Although Susskind's title and central motivation are drawn from this fascinating debate over design, most of "The Cosmic Landscape" is structured not around philosophy but around the nuts-and-bolts concepts of modern particle physics. Here Susskind's long years as a theorist and lecturer at Stanford University prove a mixed blessing. He is a good-humored and enthusiastic tour guide but he clearly does not know how baffling he sounds much of the time. He coaxes the reader along with rhetorical questions and charmingly corny allegories. Still, this isn't much help when it comes to material like "Let's suppose that the Calabi Yau manifold has a topology that is rich enough to allow 500 distinct doughnut holes through which the fluxes wind. The flux through each hole must be an integer, so a string of 500 integers has to be specified." Um, is this going to be on the exam?

Susskind's insider perspective also lends an air of smugness to the whole affair. He falls prey to the common error of Whig history: interpreting past events as if they were inevitable stepping stones to the present. He allows remarkably little doubt about string theory considering that it has, as yet, not a whit of observational support. "As much as I would very much like to balance things by explaining the opposing side, I simply can't find that other side," he writes in his concluding chapter.

Such braggadocio begs for an anthropic question of its own. Humans have been around in more or less their present form for about 150,000 years; detailed stories of the origin of the world run as far back as the first written languages and surely existed in oral form much earlier still. How likely is it that this generation, right now, is the lucky one that has discovered the final answer?

I'm not a physicist, but if I were putting money on the table, I wouldn't take those odds.

Corey S. Powell is a senior editor at Discover magazine and author of "God in the Equation: How Einstein Transformed Religion."

The following is an excerpt from Leonard Susskind's new book The Cosmic Landscape (2006).

Unfortunately, the New York Times cut off the excerpt rather abruptly, so that Professor Susskind couldn't get his point across. However, his main point, as given by the book review above, is that the universe appears to be inexplicably favorable to intelligent life (i.e. designed) only because such life will only develop in a favorable system.

For example, the fact that Earth is has just the right orbital radius from the sun is not the product of cosmic benefactor. Instead, it simply reflects the fact that if the Earth were too close or too far from the Sun, life would not exist to ponder its situation.

I haven't purchased or read the book yet, but I suspect it is a good one. After I read it, I'll let the Board know.

Without further ado: http://www.nytimes.com/2006/01/15/books/chapters/0115-1st-sussk.html?pagewanted=1


January 15, 2006
First Chapter
'The Cosmic Landscape'

By LEONARD SUSSKIND

The air is very cold and still: except for the sound of my own breathing, the silence is absolute. The dry, powdery snow crackles whenever my boot touches down. Its perfect whiteness, lit by starlight, gives the terrain a luminous, eerie brilliance, while the stars fade into a continuous glow across the black celestial dome. The night is brighter on this desolate planet than on my own home world. Beauty, but of a cold and lifeless kind: a place for metaphysical contemplation if ever there was one.

Alone, I'd left the safety of the base, to think about the day's events and to watch the sky for meteors. But it was impossible to think of anything other than the sheer enormousness and impersonal nature of the universe. The pinwheeling of galaxies, the endless expansion of the universe, the infinite coldness of space, the heat of stars being born, and their final death throes as red giants: surely this must be the point of existence.

Man-life in general-seems irrelevant to the workings of the universe: a mere smudge of water, grease, and carbon on a pinpoint planet circling a star of no special consequence.

Earlier, during the short stingy sunlight hours, Curt, Kip, and I had hiked about a mile to the Russian compound to see if we could find some Ivans to talk to. Stephen had wanted to come with us but his wheelchair could not navigate the snowdrifts. The derelict compound, just a few low rusted corrugated-metal buildings, looked deserted. We banged on the doors, but no life appeared. I cracked open the door and peered into the spooky interior darkness, then decided to brave entry and have a look around. As cold inside as it was outside, the compound was completely abandoned. The hundred or so dormitory rooms were unlocked but deserted. How did a hundred men disappear so completely? In silence we hiked back to our own base.

At the bar, we found our Russian, drinking and laughing-Victor. Victor, it seems, was one of the last three Russians left on the planet. Supplies from Russia had ceased more than a year ago. They would have starved but for the fact that our own people adopted them. We never saw the other two Russians, but Victor assured us they were alive. Victor insisted on buying me a drink, "for the cold," and asked, "How do you like this %#&*^ place?" I told him in all my travels only once had I seen the night sky even remotely as beautiful as here. Ironically, that other alien planet was so hot that the rocks would fry anything that touched them.

Of course we were not really on another planet. It only seemed that way. Antarctica is truly alien. Stephen Hawking, Curt Callan, Kip Thorne, Stan Deser, Claudio Teitelboim, myself, our wives, and a few other theoretical physicists were there for fun-as a lark-a reward for coming to Chile for a conference on black holes. Claudio, an eminent Chilean physicist, had arranged for the Chilean Air Force to fly us in one of its giant Hercules cargo planes to their Antarctic base for a couple of days.

It was August 1997-winter in the southern hemisphere-and we were expecting the worst. The coldest I had ever experienced was 20 below zero Fahrenheit, and I was worried about how well I would handle the 60 below that can grip the base in midwinter. When the plane landed, we anxiously zipped up the heavy Arctic gear that the military had provided and prepared for the fearful cold.

Then the cargo hold opened, and Curt's wife, Chantal, bounded out of the plane, threw up her arms, and joyously yelled back, "It's about as cold as a winter day in New Jersey." And so it was. It stayed that way for the whole day while we frolicked in the snow.

Sometime during that night the beast awoke. By morning Antarctica had unleashed its fury. I went outside for a couple of minutes to get a taste of what Shackleton and his shipwrecked men had endured. Why hadn't they all perished? Not a single member of the expedition was lost. Freezing cold and soaking wet for more than a year, why didn't they all die of pneumonia? Out there in the blast of the storm, I knew the answer: nothing survives-not even the microbes that give men colds.

The other alien "planet" I'd mentioned to Victor was Death Valley- another lifeless place. No, not quite lifeless. But I wondered how much hotter it would have to get to fry all protoplasm. What Antarctica has in common with Death Valley is extreme dryness. It's too cold for much water vapor to be suspended in the air-that and the complete lack of light pollution make it possible, in both extremes, to see the stars in a way that modern man rarely can. Standing there in the Antarctic starlight, it occurred to me how lucky we humans are. Life is fragile: it thrives only in a narrow range of temperatures between freezing and boiling. How lucky that our planet is just the right distance from the sun: a little farther, and the death of the perpetual Antarctic winter-or worse-would prevail; a little closer, and the surface would truly fry anything that touched it. Victor, being Russian, took a spiritual view of the question. "Was it not," he asked, "God's infinite kindness and love that permitted our existence?" My own "mindless" explanation will become clear in good time.

In fact we have much more to be thankful for than just the earth's temperature. Without the right amount of carbon, oxygen, nitrogen, and other elements, a temperate climate would be wasted. If the sun at the center of our solar system were replaced by the more common binary star system, planetary orbits would be too chaotic and unstable for life to have evolved. There are endless dangers of this kind. But on top of all these are the laws of nature themselves. All it takes is a small change in Newton's laws, or the rules of atomic physics, and poof-life would either be instantly extinguished or would never have formed. It seems that our guardian angel not only provided us with a very benign planet to live on but also made the rules of existence-the laws of physics and cosmology-just right for us. This is one of the greatest mysteries of nature. Is it luck? Is it intelligent and benevolent design? Is it at all a topic for science-for metaphysics-for religion?

This book is about a debate that is stirring the passions of physicists and cosmologists but is also part of a broader controversy, especially in the United States, where it has entered the partisan political discourse. On one side are the people who are convinced that the world must have been created or designed by an intelligent agent with a benevolent purpose. On the other side are the hard-nosed, scientific types who feel certain that the universe is the product of impersonal, disinterested laws of physics, mathematics, and probability-a world without a purpose, so to speak. By the first group, I don't mean the biblical literalists who believe the world was created six thousand years ago and are ready to fight about it. I am talking about thoughtful, intelligent people who look around at the world and have a hard time believing that it was just dumb luck that made the world so accommodating to human beings. I don't think these people are being stupid; they have a real point.

The advocates of intelligent design generally argue that it is incredible that anything as complex as the human visual system could have evolved by purely random processes. It is incredible! But biologists are armed with a very powerful tool-the Principle of Natural Selection- whose explanatory power is so great that almost all biologists believe the weight of evidence is strongly in favor of Darwin. The miracle of the eye is only an apparent miracle.

I think the design enthusiasts are on better ground when it comes to physics and cosmology. Biology is only part of the story of creation. The Laws of Physics and the origin of the universe are the other part, and here again, incredible miracles appear to abound. It seems hopelessly improbable that any particular rules accidentally led to the miracle of intelligent life. Nevertheless, this is exactly what most physicists have believed: intelligent life is a purely serendipitous consequence of physical principles that have nothing to do with our own existence. Here I share the skepticism of the intelligent-design crowd: I think that the dumb luck needs an explanation. But the explanation that is emerging from modern physics is every bit as different from intelligent design as Darwin's was from "Soapy" Sam Wilberforce's.

The debate that this book is concerned with is not the bitter political controversy between science and creationism. Unlike the debate between "Darwin's Bulldog" Thomas Huxley and Wilberforce, the present argument is not between religion and science but between two warring factions of science-those who believe, on the one hand, that the laws of nature are determined by mathematical relations, which by mere chance happen to allow life, and those who believe that the Laws of Physics have, in some way, been determined by the requirement that intelligent life be possible. The bitterness and rancor of the controversy have crystallized around a single phrase-the Anthropic Principle-a hypothetical principle that says that the world is fine-tuned so that we can be here to observe it! By itself I would have to say that this is a silly, half-baked notion. It makes no more sense than saying that the reason the eye evolved is so that someone can exist to read this book. But it is really shorthand for a much richer set of concepts that I will make clear in the chapters that follow.

But the controversy among scientists does have repercussions for the broader public debate. Not surprisingly, it does overflow the seminar rooms and scientific journals into the political debates about design and creationism. Christian Internet sites have leapt into the fray:

The Bible says: "From the time the world was created, people have seen the earth and the sky and all that God made. They can clearly see His invisible qualities-His eternal power and divine nature. So they have no excuse whatsoever for not knowing God."

This is as true today as it ever has been-in some ways, with the discovery of the Anthropic Principle, it is more true now than ever before. So the first kind of evidence that we have is the creation itself-a universe that carries God's signature-a universe "just right" for us to live in.

And from another religious site:

In his book "The Cosmic Blueprint," the astronomer professor Paul Davies concludes that the evidence for design is overwhelming: Professor Sir Fred Hoyle-no sympathizer with Christianity-says that it looks as if a super-intellect has monkeyed with physics as well as with chemistry and biology.

And the astronomer George Greenstein says: As we survey all the evidence, the thought insistently arises that some supernatural agency, or rather Agency, must be involved. Is it possible that suddenly, without intending to, we have stumbled upon scientific proof of the existence of a supreme being? Was it God who stepped in and so providentially created the cosmos for our benefit?

Is it any wonder that the Anthropic Principle makes many physicists very uncomfortable?

Davies and Greenstein are serious scholars, and Hoyle was one of the great scientists of the twentieth century. As they point out, the appearance of intelligent design is undeniable. Extraordinary coincidences are required for life to be possible. It will take us a few chapters to fully understand this "elephant in the room," but let's begin with a sneak preview. The world as we know it is very precarious, in a sense that is of special interest to physicists. There are many ways it could go bad-so bad that life as we know it would be totally impossible. The requirements that the world be similar enough to our own to support conventional life fall into three broad classes. The first class involves the raw materials of life: chemicals. Life is, of course, a chemical process. Something about the way atoms are constructed makes them stick together in the most bizarre combinations: the giant crazy Tinkertoy molecules of life-DNA, RNA, hundreds of proteins, and all the rest. Chemistry is really a branch of physics: the physics of the valence electrons, i.e., those that orbit the nucleus at the outer edges of the atom. It's the valence electrons hopping back and forth or being shared between atoms that gives the atoms their amazing abilities.

The Laws of Physics begin with a list of elementary particles like electrons, quarks, and photons, each with special properties such as mass and electric charge. These are the objects that everything else is built out of. No one knows why the list is what it is or why the properties of these particles are exactly what they are. An infinite number of other lists is equally possible. But a universe filled with life is by no means a generic expectation. Eliminating any of these particles (electrons, quarks, or photons), or even changing their properties a modest amount, would cause conventional chemistry to collapse. This is obviously so for the electrons and for the quarks that make up protons and neutrons. Without these there could be no atoms at all. But the importance of the photon may be less obvious. In later chapters we will learn about the origin of forces like electric and gravitational forces, but for now it's enough to know that the electric forces that hold the atom together are consequences of the photon and its special properties. If the laws of nature seem well chosen for chemistry, they are also well chosen for the second set of requirements, namely, that the evolution of the universe provided us with a comfortable home to live in. The largescale properties of the universe-its size; how fast it grows; the existence of galaxies, stars, and planets-are mainly governed by the force of gravity. It's Einstein's theory of gravity-the General Theory of Relativity- that explains how the universe expanded from the initial hot Big Bang to its present large size. The properties of gravity, especially its strength, could easily have been different. In fact it is an unexplained miracle that gravity is as weak as it is. The gravitational force between electrons and the atomic nucleus is ten thousand billion billion billion billion times weaker than the electrical attraction. Were the gravitational forces even a little stronger, the universe would have evolved so quickly that there would have been no time for intelligent life to arise. But gravity plays a very dramatic role in the unfolding of the universe. Its pull causes the material in the universe-hydrogen, helium, and the so-called dark matter-to clump, into galaxies, stars, and finally planets. However, for this to happen, the very early universe must have been a bit lumpy. If the original material of the universe had been smoothly distributed, it would have stayed that way for all time. In fact, fourteen billion years ago, the universe was just lumpy enough-a bit lumpier or a bit less lumpy, and there would have been no galaxies, stars, or planets for life to evolve on.

Finally, there is the actual chemical composition of the universe. In the beginning there were only hydrogen and helium: certainly not sufficient for the formation of life. Carbon, oxygen, and all the others came later. They were formed in the nuclear reactors in the interiors of stars. But the ability of stars to transmute hydrogen and helium into the all-important carbon nuclei was a very delicate affair. Small changes in the laws of electricity and nuclear physics could have prevented the formation of carbon.

Even if the carbon, oxygen, and other biologically important elements were formed inside stars, they had to get out in order to provide the material for planets and life. Obviously we cannot live in the intensely hot cores of stars. How did the material escape the stellar interior? The answer is that it was violently ejected in cataclysmic supernova explosions. Supernova explosions themselves are remarkable phenomena. In addition to protons, neutrons, electrons, photons, and gravity, supernovae require yet another particle-the ghostly neutrino previously mentioned. The neutrinos, as they escape from the collapsing star, create a pressure that pushes the elements in front of them. And, fortunately, the list of elementary particles happens to include neutrinos with the right properties. . . .

dalem
15 Jan 06,, 20:13
Unfortunately, the New York Times cut off the excerpt rather abruptly, so that Professor Susskind couldn't get his point across. However, his main point, as given by the book review above, is that the universe appears to be inexplicably favorable to intelligent life (i.e. designed) only because such life will only develop in a favorable system.

For example, the fact that Earth is has just the right orbital radius from the sun is not the product of cosmic benefactor. Instead, it simply reflects the fact that if the Earth were too close or too far from the Sun, life would not exist to


And isn't it a fantastic coincidence that my legs are long enough to reach the ground?

-dale

Bulgaroctonus
15 Jan 06,, 22:20
And isn't it a fantastic coincidence that my legs are long enough to reach the ground?

-dale
First, I have to apologize for that paragraph of my post ending abruptly, I did correct it to read "life would not exist to ponder its situation."

I assume you're being humorous here. On the off chance that you are not, I'll say that is not a coincidence that your legs are long enough to reach the ground. Natural selection, not an intelligent agent, has given you competent legs.

Anyway, Susskind's book doesn't deal primarily with evolutionary debates about intelligent design. He writes about the most fundamental things like sub-atomic laws. Some scientists have claimed that there must be a creator since the gravitational constant G (6.67 x 10-11 Nm2/kg2) is just right for life.

However, this is just faulty thinking. The universe appears artificially favorable because intelligent life only evolves under favorable circumstances. If the gravitational constant were 7.67 x 10-11 Nm2/kg2, there would be no life to worry about it.

Parihaka
15 Jan 06,, 22:26
And isn't it a fantastic coincidence that my legs are long enough to reach the ground?

-dale
God damn, I wade through this stuff, come up with what I consider a sufficiently cutting response and find at the end you've done it much better than I could. :mad:

Parihaka
15 Jan 06,, 22:29
. The universe appears artificially favorable because intelligent life only evolves under favorable circumstances. .
I would say that life evolves to suit the circumstances. I've seen nothing to indicate that life can't evolve and survive in almost any environment, just not life as we know it. Jim.

Bulgaroctonus
15 Jan 06,, 23:01
I would say that life evolves to suit the circumstances. I've seen nothing to indicate that life can't evolve and survive in almost any environment, just not life as we know it. Jim.
Well, if the a few physical constants were different from their actual value, life would not exist. For example, Mercury has no life on it because it is too close to the Sun. So, that's a pretty good example that life can't adapt to every situation.

Similarly, if the cosmic gravitational constant were larger, than the universe would have progressed much differently than it has. In all probabality, life would not have evolved. Susskind mentioned this example.

The adaptation you speak of is only on Earth and within a relatively small variation of temperature, pressure, radiation, and chemical environment. Life has a small window to survive in.

Parihaka
15 Jan 06,, 23:20
Well, if the a few physical constants were different from their actual value, life would not exist. For example, Mercury has no life on it because it is too close to the Sun. So, that's a pretty good example that life can't adapt to every situation. While I agree that Mercury probably has no life on it you cannot prove this. Every indicator from Earth where we can actually examine it is that life can adapt/evolve virtually anywhere and this is the only real data that we have, Geothermal vents under water for instance. Organisms that feed off the chemical discharges of these volcanoes under immense pressure and extreme heat.


Similarly, if the cosmic gravitational constant were larger, than the universe would have progressed much differently than it has. In all probabality, life would not have evolved. Susskind mentioned this example. Again, you can have no proof of this.


The adaptation you speak of is only on Earth and within a relatively small variation of temperature, pressure, radiation, and chemical environment. Life has a small window to survive in.Life as we know it yes, but the only determinant we can really prove about life on earth is that it requires energy and elements to survive. It seems that virtually any environment which we have examined requires only energy acting on basic elements for life to exist. Any claims of life not existing elsewhere is purely supposition.

Bulgaroctonus
16 Jan 06,, 00:46
While I agree that Mercury probably has no life on it you cannot prove this. Every indicator from Earth where we can actually examine it is that life can adapt/evolve virtually anywhere and this is the only real data that we have, Geothermal vents under water for instance. Organisms that feed off the chemical discharges of these volcanoes under immense pressure and extreme heat.
Surface temperatures on Mercury range from about 90-700 K (-183 C to 427 C). Meanwhile, the geothermal (actually hydrothermal if underwater) vents you mention only get as hot as 60 C, or 443 K. Therefore, even the most extreme terrestrial life is still far less extreme than the conditions of Mercury.

I think most astronomers and chemists will say that there is no life on Mercury. Requiring proof of it is not very important, since the temperatures and radiation levels are simply too inclement to allow life, according to mathematical models of life.

You can say, "Oh you can't prove that" to anything anyone says. Its not a very good objection. I'll make an argument of probability. For example, there is an extremely low probability of life occuring on Mercury.


Again, you can have no proof of this.
First remember that Susskind is talking about intelligent life. That's because he's concerned with the fallacy of cosmic intelligent design. So, if some insignificant bacterial life exists, it's no great feat.

Anyway, an alteration in the gravitational constant would have large impacts that we can show with simple mathematics. Of course, we can't empirically prove the effects of a change in gravitational constant because we cannot produce a change in the gravitational constant, precisely the reason it is 'cosmic.'

The force of gravity between two masses is given by the formula GMm/r^2. G = the gravitational constant = 6.67 x 10^-11 Nm^2/kg^2. M = one mass, m = the other mass, and r is the distance between the two objects. Similarly, the acceleration produced by a gravitational field around mass M is given by a=GM/r^2. Plug in the values for Earth's mass (5.98 x 10^24 kg) and its mean radius (6.37 x 10^6 m) and you'll find the acceleration is 9.81 m/s^2.

Now, if we shifted the gravitational constant to G = 6.67 x 10^-10, we would have a much different situation. Now, the acceleration of gravity on Earth's surface is 98.1 m/s^2. I weigh about 160 lbs, about 72 kg. Under normal gravity, I weigh about 706.32 Newtons. However, if the gravitational acceleration was ten times as large, I would weigh a crushing 7063.2 N!

This fact alone would make life on our planet very different, if not impossible. The effects of a vastly different gravitational constant would be, of course, vastly worse from our perspective.

The effects of a diffent gravitational constant would also make the universe more rapidly or less rapidly than it has. Gravity determines how fast stars form, burn through their fuel, and then die. A star is driven by fusion, this fusion is caused by the tremendous velocity of helium and hydrogen atoms, a velocity caused by gravitational force. If the gravitational force constant were greater, then stars would burn out faster. If the gravitational constant were great enough, the stars would burn out two fast for evolution of intelligent life, or life at all, to occur.

So, through simple reasoning, we can show that a different gravitational constant would produce a universe very inimical to life.


Life as we know it yes, but the only determinant we can really prove about life on earth is that it requires energy and elements to survive. It seems that virtually any environment which we have examined requires only energy acting on basic elements for life to exist. Any claims of life not existing elsewhere is purely supposition.
Life requires much more than just energy and elements. There must be just the right amount of radiation, or energy, and the right kind of elements. In a harsher universe, there would be amounts of energy and different elements that did not allow the creation of life. Simply look at Mercury again. Sure, it has energy and elements, but it is getting too much energy. In addition, it doesn't have the right elements to make life. For example, its atmosphere is basically non-existent. In addition, it has no aqueous water that is the essential ingredient of life on Earth.

In addition, there are no scientists that definitely rule out the existence of life in other places in the universe. They simply say that the statistical odds of extraterrestrial life are slim since there is such a small window for life's existence elsewhere.

Look at the rest of the solar system. Even other planets within the same solar system don't have life, and we can assume that conditions throughout the whole universe are much greater in variation.

Parihaka
16 Jan 06,, 01:20
Surface temperatures on Mercury range from about 90-700 K (-183 C to 427 C). Meanwhile, the geothermal (actually hydrothermal if underwater) vents you mention only get as hot as 60 C, or 443 K. Therefore, even the most extreme terrestrial life is still far less extreme than the conditions of Mercury.


Analyzing ash, lava and magma chemical compositions from nine representative volcanoes around the world, geologists Everett L. Shock, Ph.D., professor of earth and planetary sciences in Arts and Sciences at Washington University, and Mikhail Y. Zolotov, Ph.D., senior research scientist, describe a scenario where initial volcanic gases spewing from the Earth as hot as 1200 degrees Celsius cool down to a relatively low temperature of between 150-300 degrees C. Shock and Zolotov have shown that, in this temperature range, environmental and chemical conditions are ripe for basic hydrocarbons -- a wide range of carbon-based compounds essential for life -- to form from the hydrogen and carbon monoxide present in the volcanic gases. They say that a naturally occurring catalytic reaction, similar to a famous industrial process called Fischer-Tropsch synthesis, involves the iron compound magnetite as catalyst, and is an essential part of the process.

From here (http://www.sciencedaily.com/releases/2000/03/000328085015.htm)


I think most astronomers and chemists will say that there is no life on Mercury. Requiring proof of it is not very important, since the temperatures and radiation levels are simply too inclement to allow life, according to mathematical models of life.
While I agree that Mercury probably has no life on it you cannot prove this.


You can say, "Oh you can't prove that" to anything anyone says. Its not a very good objection. I would have assumed that the requirement of some degree of proof was essential to any form of discussion of this nature :rolleyes:


First remember that Susskind is talking about intelligent life. That's because he's concerned with the fallacy of cosmic intelligent design. So, if some insignificant bacterial life exists, it's no great feat. Really?


Anyway, an alteration in the gravitational constant would have large impacts that we can show with simple mathematics. Of course, we can't empirically prove the effects of a change in gravitational constant because we cannot produce a change in the gravitational constant, precisely the reason it is 'cosmic.'

The force of gravity between two masses is given by the formula GMm/r^2. G = the gravitational constant = 6.67 x 10^-11 Nm^2/kg^2. M = one mass, m = the other mass, and r is the distance between the two objects. Similarly, the acceleration produced by a gravitational field around mass M is given by a=GM/r^2. Plug in the values for Earth's mass (5.98 x 10^24 kg) and its mean radius (6.37 x 10^6 m) and you'll find the acceleration is 9.81 m/s^2.

Now, if we shifted the gravitational constant to G = 6.67 x 10^-10, we would have a much different situation. Now, the acceleration of gravity on Earth's surface is 98.1 m/s^2. I weigh about 160 lbs, about 72 kg. Under normal gravity, I weigh about 706.32 Newtons. However, if the gravitational acceleration was ten times as large, I would weigh a crushing 7063.2 N!

This fact alone would make life on our planet very different, if not impossible. The effects of a vastly different gravitational constant would be, of course, vastly worse from our perspective. All you are demonstrating is that life as we know it on earth would be unlikely in this scenario, not that any form of life is impossible


The effects of a diffent gravitational constant would also make the universe more rapidly or less rapidly than it has. Gravity determines how fast stars form, burn through their fuel, and then die. A star is driven by fusion, this fusion is caused by the tremendous velocity of helium and hydrogen atoms, a velocity caused by gravitational force. If the gravitational force constant were greater, then stars would burn out faster. If the gravitational constant were great enough, the stars would burn out two fast for evolution of intelligent life, or life at all, to occur.

So, through simple reasoning, we can show that a different gravitational constant would produce a universe very inimical to life. See above



Life requires much more than just energy and elements. There must be just the right amount of radiation, or energy, and the right kind of elements. In a harsher universe, there would be amounts of energy and different elements that did not allow the creation of life. Simply look at Mercury again. Sure, it has energy and elements, but it is getting too much energy. In addition, it doesn't have the right elements to make life. For example, its atmosphere is basically non-existent. In addition, it has no aqueous water that is the essential ingredient of life on Earth. See Above. As the hydrothermal vents illustrates, the conditions for life as we know it are constantly being revised. This is known. Your suppositions are not.


In addition, there are no scientists that definitely rule out the existence of life in other places in the universe. They simply say that the statistical odds of extraterrestrial life are slim since there is such a small window for life's existence elsewhere. Any actual quotes or evidence for this?


Look at the rest of the solar system. Even other planets within the same solar system don't have life, and we can assume that conditions throughout the whole universe are much greater in variation.Any evidence of this?
After all
The calculations show not only that life can arise from the gaseous crucible of present day terrestrial volcanoes, but that it was even more likely to develop billions of years ago on early Earth, Mars and Jupiter's satellite, Europa. There is a solid body of evidence that shows the temperature of magma then would have been about 200 degrees C hotter than now and that the atmosphere would have been less oxidized. The Shock/Zolotov calculations show that higher initial temperatures of spewing volcanic gases are more favorable for organic synthesis, once the gases dilute and cool to the hydrocarbon-forming zone of 150-300 degrees C.


Within three bodies of this solar system it is/was perfectly possible for life similar to ours to have begun, one definitely did and attained intelligence.
I would regard it as extremely unlikely that factors for life didn't exist in other areas of the universe that have different attributes, and therefore the life within those areas also having different attributes, which takes us back to my original point that life develops to suite the conditions.

dalem
16 Jan 06,, 01:30
However, this is just faulty thinking. The universe appears artificially favorable because intelligent life only evolves under favorable circumstances. If the gravitational constant were 7.67 x 10-11 Nm2/kg2, there would be no life to worry about it.

Why not?

-dale

Bill
16 Jan 06,, 18:23
And isn't it a fantastic coincidence that my legs are long enough to reach the ground?

-dale

They have to be. If they were too short, you'd simply fall until they did touch the ground. :)

Bulgaroctonus
17 Jan 06,, 01:03
Parihaka,

It appears you are not satisfied with my argument. Therefore, I must dredge up some sources and present a fully referenced post. This will take some time, since I must do other things. I also want to make it a good post so I can close the argument out in one fell swoop, with none of the common banter for twenty posts.

I still stand by what I've posted. I think I have my basic physics and chemistry right, but I could be making an error somewhere. I will look over my text books and materials to make sure I'm not in error.

I will also go over my organic chemistry materials to address the limitations of life that we have been writing about. I still maintain that there is a definite environmental limit to the existence of life, and I can probably find the proper chemical justification for this.

I also maintain that a significant shift in the cosmic gravitational constant could disable the evolution of life. This isn't primarily because life would be too 'heavy' but because the evolution of the universe would happen too quickly or too slowly. This is because gravity affects the burn rate of stars. Anyway, I'll elaborate on that in the next post.

I'm not making any promises as to when I will post a good reply. If I say tommorrow, then I'll probably be to busy and I'll be forced to break my word.

However, a reply will come. I want to have integrity as an amateur scientist, so I'll be as humble on this issue as possible.

I look forward to a good scientific debate.

Parihaka
17 Jan 06,, 01:19
Parihaka,

I look forward to a good scientific debate.
You're missing the point Bulgar. By all means conduct your research, but all you will achieve is to prove what I already know, that there are conditions in this universe under which life as we measure it cannot exist.
That doesn't mean that in a different universe with different conditions, that life which suits those conditions cannot develop. I am simply contending that life develops to suit the physical conditions of the theoretical universe, if you can theorise the universe, you can theorise the life which can develop in it. You cannot use the model of life within our universe as a model for life in your theoretical universe.