Category: Science

Tetman Callis 0 Comments 7:20 am

“Mammals and dinosaurs diverged from a common ancestor about 260 million years ago. Dinosaurs subsequently evolved to fill every possible ecological niche, from which they ruled the earth for 160 million years and became the most successful vertebrates in the history of the planet. During all that time we mammals managed to evolve into nothing larger than a cat.” – Elizabeth Marshall Thomas, “First Fine Careless Raptor”

Tetman Callis 0 Comments 7:31 am

“It seems clear that untreated trauma arising from abuse during childhood constitutes a major risk factor for a variety of mental health and social problems later in life. The implications of this relationship are substantial. They suggest that some significant proportion of the psychological and psychosocial difficulties of adolescents and adults are directly attributable to childhood maltreatment.” – John M. Briere, Child Abuse Trauma: Theory and Treatment of the Lasting Effects

Tetman Callis 0 Comments 7:01 am

“We were proved right. It didn’t seem to matter.” – Dr. Kate Marvel, “I’m a Climate Scientist. I’m not Screaming Into the Void Anymore”

Tetman Callis 0 Comments 7:56 am

“Extreme poverty and homelessness exemplify ways in which American society fails to provide minimal support for many of its citizens and, as a result, indirectly maltreats large numbers of children.” – John M. Briere, Child Abuse Trauma: Theory and Treatment of the Lasting Effects

Tetman Callis 0 Comments 8:17 am

“You would, at first sight, think that a low-energy electron would have great difficulty passing through a solid crystal. The atoms are packed together with their centers only a few angstroms apart, and the effective diameter of the atom for electron scattering is roughly an angstrom or so. That is, the atoms are large, relative to their spacing, so that you would expect the mean free path between collisions to be of the order of a few angstroms—which is practically nothing. You would expect the electron to bump into one atom or another almost immediately. Nevertheless, it is a ubiquitous phenomenon of nature that if the lattice is perfect, the electrons are able to travel through the crystal smoothly and easily—almost as if they were in a vacuum. This strange fact is what lets metals conduct electricity so easily; it has also permitted the development of many practical devices. It is, for instance, what makes it possible for a transistor to imitate the radio tube. In a radio tube electrons move freely through a vacuum, while in the transistor they move freely through a crystal lattice.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. III

Tetman Callis 0 Comments 8:17 am

“If you were to throw 10 billion photons at a polarizing filter, and the average probability of each one going through is, say, 3/4, you would expect 3/4 of 10 billion would get through. Likewise, the energy that they would carry would be 3/4 of the energy that you attempted to put through. Classical theory says nothing about the statistics of the thing—it simply says that the energy that comes through will be precisely 3/4 of the energy which you were sending in. That is, of course, impossible if there is only one photon. There is no such thing as 3/4 of a photon. It is either all there, or it isn’t there at all. Quantum mechanics tells us it is all there 3/4 of the time.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. III

Tetman Callis 0 Comments 7:47 am

“Quantum mechanics is a different kind of a theory to represent the world. . . . Nature knows the quantum mechanics, and the classical mechanics is only an approximation; so there is no mystery in the fact that in classical mechanics there is some shadow of quantum mechanical laws—which are truly the ones underneath. To reconstruct the original object from the shadow is not possible in any direct way, but the shadow does help you to remember what the object looks like. . . . We must always go back to the real world and discover the correct quantum mechanical equations. When they come out looking like something in classical physics, we are in luck.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. III

Tetman Callis 0 Comments 8:03 am

“If you think technology is going to solve your problems, you don’t understand technology, and you don’t understand your problems.” – Laurie Anderson (interviewed by Anderson Cooper)

Tetman Callis 0 Comments 7:31 am

“We speak with remarkable laxness and imprecision and yet manage to express ourselves with wondrous subtlety—and simply breathtaking speed. In normal conversation we speak at a rate of about 300 syllables a minute. To do this we force air up through the larynx—or supralaryngeal vocal tract, to be technical about it—and, by variously pursing our lips and flapping our tongues around in our mouth rather in the manner of a freshly landed fish, we shape each passing puff of air into a series of loosely differentiated plosives, fricatives, gutturals, and other minor atmospheric disturbances. These emerge as a more or less continuous blur of sound. People don’t talk like this, theytalklikethis. Syllables, words, and sentences run together like a watercolor left in the rain. To understand what anyone is saying to us we must separate these noises into words and the words into sentences so that we might in our turn issue a string of mixed sounds in response. If what we say is suitably apt and amusing, the listener will show his delight by emitting a series of uncontrolled high-pitched noises, accompanied by sharp intakes of breath of the sort normally associated with a seizure or heart failure. And by these means we converse. Talking, when you think about it, is a very strange business indeed.” – Bill Bryson, The Mother Tongue: English and How It Got That Way

Tetman Callis 0 Comments 7:16 am

“The trouble with quantum mechanics is not only in solving the equations but in understanding what the solutions mean.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. III

Tetman Callis 0 Comments 9:11 am

“If a tree falls in a forest and there is nobody there to hear it, does it make a noise? A real tree falling in a real forest makes a sound, of course, even if nobody is there. Even if no one is present to hear it, there are other traces left. The sound will shake some leaves, and if we were careful enough we might find somewhere that some thorn had rubbed against a leaf and made a tiny scratch that could not be explained unless we assumed the leaf were vibrating. So in a certain sense we would have to admit that there is a sound made. We might ask: was there a sensation of sound? No, sensations have to do, presumably, with consciousness. And whether ants are conscious and whether there were ants in the forest, or whether the tree was conscious, we do not know.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. III (emphases in original)

Tetman Callis 0 Comments 7:45 am

“It turns out—although it is not at all self-evident—that in all circumstances where it has been experimentally checked, the velocity of a fluid is exactly zero at the surface of a solid. You have noticed, no doubt, that the blade of a fan will collect a thin layer of dust—and that it is still there after the fan has been churning up the air. You can see the same effect even on the great fan of a wind tunnel. Why isn’t the dust blown off by the air? In spite of the fact that the fan blade is moving at high speed through the air, the speed of the air relative to the fan blade goes to zero right at the surface. So the very smallest dust particles are not disturbed.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 7:49 am

“To imagine a man perfectly free and not subject to the law of inevitability, we must imagine him all alone, beyond space, beyond time, and free from dependence on cause.” – Leo Tolstoy, War and Peace (trans. Louise and Aylmer Maude)(emphases in original)

Tetman Callis 0 Comments 7:31 am

“Absolute continuity of motion is not comprehensible to the human mind. Laws of motion of any kind become comprehensible to man only when he examines arbitrarily selected elements of that motion; but at the same time, a large proportion of human error comes from the arbitrary division of continuous motion into discontinuous elements. There is a well known, so-called sophism of the ancients consisting in this, that Achilles could never catch up with a tortoise he was following, in spite of the fact that he traveled ten times as fast as the tortoise. By the time Achilles has covered the distance that separated him from the tortoise, the tortoise has covered one tenth of that distance ahead of him: when Achilles has covered that tenth, the tortoise has covered another one hundredth, and so on forever. This problem seemed to the ancients insoluble. The absurd answer (that Achilles could never overtake the tortoise) resulted from this: that motion was arbitrarily divided into discontinuous elements, whereas the motion both of Achilles and of the tortoise was continuous. By adopting smaller and smaller elements of motion we only approach a solution of the problem, but never reach it. Only when we have admitted the conception of the infinitely small, and the resulting geometrical progression with a common ratio of one tenth, and have found the sum of this progression to infinity, do we reach a solution of the problem. A modern branch of mathematics having achieved the art of dealing with the infinitely small can now yield solutions in other more complex problems of motion which used to appear insoluble. This modern branch of mathematics, unknown to the ancients, when dealing with problems of motion admits the conception of the infinitely small, and so conforms to the chief condition of motion (absolute continuity) and thereby corrects the inevitable error which the human mind cannot avoid when it deals with separate elements of motion instead of examining continuous motion. In seeking the laws of historical movement just the same thing happens. The movement of humanity, arising as it does from innumerable arbitrary human wills, is continuous. To understand the laws of this continuous movement is the aim of history. But to arrive at these laws, resulting from the sum of all those human wills, man’s mind postulates arbitrary and disconnected units. The first method of history is to take an arbitrarily selected series of continuous events and examine it apart from others, though there is and can be no beginning to any event, for one event always flows uninterruptedly from another. The second method is to consider the actions of some one man—a king or a commander—as equivalent to the sum of many individual wills; whereas the sum of individual wills is never expressed by the activity of a single historic personage. Historical science in its endeavor to draw nearer to truth continually takes smaller and smaller units for examination. But however small the units it takes, we feel that to take any unit disconnected from others, or to assume a beginning of any phenomenon, or to say that the will of many men is expressed by the actions of any one historic personage, is in itself false. It needs no critical exertion to reduce utterly to dust any deductions drawn from history. It is merely necessary to select some larger or smaller unit as the subject of observation—as criticism has every right to do, seeing that whatever unit history observes must always be arbitrarily selected. Only by taking infinitesimally small units for observation (the differential of history, that is, the individual tendencies of men) and attaining to the art of integrating them (that is, finding the sum of these infinitesimals) can we hope to arrive at the laws of history.” – Leo Tolstoy, War and Peace (trans. Louise and Aylmer Maude)(emphases in original)

Tetman Callis 0 Comments 5:51 am

“In quantum mechanics the angular momentum of a thing does not have an arbitrary direction, but its component along a given axis can take on only certain equally spaced, discrete values. It is a shocking and peculiar thing. . . . There isn’t any descriptive way of making it intelligible that isn’t so subtle and advanced in its own form that it is more complicated than the thing you were trying to explain. The behavior of matter on a small scale is different from anything that you are used to and is very strange indeed. . . . It is a good idea to try to get a growing acquaintance with the behavior of things on a small scale, at first as a kind of experience without any deep understanding. Understanding of these matters comes very slowly, if at all. Of course, one does get better able to know what is going to happen in a quantum-mechanical situation—if that is what understanding means—but one never gets a comfortable feeling that these quantum-mechanical rules are ‘natural’ . . . . It would be dishonest to describe the magnetic properties of materials without mentioning the fact that the classical description of magnetism—of angular momentum and magnetic moments—is incorrect.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 7:50 am

“If you watch videos of falling cats, you will see that a lot of them use their tails to turn over. But we also know that cats without tails can turn over just fine. So from a physics point of view, the problem has reached a level where the details depend on the specific cat. People will still argue about it. I think a lot of physicists don’t realize how complicated the problem is, and they’re often just looking for a single simple solution. Physicists have an instinct to look for simple solutions, but nature’s always looking for the most effective solution. And those two approaches are not always the same.” – Greg Gbur, “The Surprisingly Complicated Physics of Why Cats Always Land on Their Feet” (interview by Jennifer Ouellette in Ars Technica, December 25, 2019)

Tetman Callis 0 Comments 7:10 am

“Balancing involves making a correction for what is going wrong. And this is not possible, in general, if there are several things going wrong at once.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 7:49 am

“The total charge in the world is always constant—there is never any net gain or loss of charge.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 6:25 am

“Human sciences dissect everything to comprehend it, and kill everything to examine it.” – Leo Tolstoy, War and Peace (trans. Louise and Aylmer Maude)

Tetman Callis 0 Comments 7:00 am

“Whenever you see a sweeping statement that a tremendous amount can come from a very small number of assumptions, you always find that it is false. There are usually a large number of implied assumptions that are far from obvious if you think about them sufficiently carefully.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 6:17 am

“What we call the stars are only inferences, inferences drawn from the only physical reality we have yet gotten from them—from a careful study of the unendingly complex undulations of the electric and magnetic fields reaching us on earth.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 7:27 am

“By experiments with charges and currents we find a number c2 which turns out to be the square of the velocity of propagation of electromagnetic influences. From static measurements—by measuring the forces between two unit charges and between two unit currents—we find that c=3.00×108 meters/sec. When [James Clerk] Maxwell first made this calculation with his equations, he said that bundles of electric and magnetic fields should be propagated at this speed. He also remarked on the mysterious coincidence that this was the same as the speed of light. ‘We can scarcely avoid the inference,’ said Maxwell, ‘that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena.’ Maxwell had made one of the great unifications of physics. Before his time, there was light, and there was electricity and magnetism. The latter two had been unified by the experimental work of Faraday, Oersted, and Ampère. Then, all of a sudden, light was no longer ‘something else,’ but was only electricity and magnetism in this new form—little pieces of electric and magnetic fields which propagate through space on their own.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 6:34 am

“One of the basic laws of physics is that electric charge is indestructible; it is never lost or created. Electric charges can move from place to place but never appear from nowhere. We say that charge is conserved.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II (emphases in original)

Tetman Callis 0 Comments 7:17 am

“The total amount of information which has been acquired about the physical world since the beginning of scientific progress is enormous, and it seems almost impossible that any one person could know a reasonable fraction of it. But it is actually quite possible for a physicist to retain a broad knowledge of the physical world rather than to become a specialist in some narrow area. The reasons for this are threefold: First, there are great principles which apply to all the different kinds of phenomena—such as the principles of the conservation of energy and of angular momentum. A thorough understanding of such principles gives an understanding of a great deal all at once. Second, there is the fact that many complicated phenomena, such as the behavior of solids under compression, really basically depend on electrical and quantum-mechanical forces, so that if one understands the fundamental laws of electricity and quantum mechanics, there is at least some possibility of understanding many of the phenomena that occur in complex situations. Finally, there is a most remarkable coincidence: The equations for many different physical situations have exactly the same appearance. Of course, the symbols may be different—one letter is substituted for another—but the mathematical form of the equations is the same. This means that having studied one subject, we immediately have a great deal of direct and precise knowledge about the solutions of the equations of another.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 6:36 am

“Whenever one is trying to understand a new phenomenon it is a good idea to take a somewhat oversimplified model; then, having understood the problem with that model, one is better able to proceed to tackle the more exact calculation.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 6:42 am

“The more clearly you picture the history of life as an unbroken series of ecosystems, and not just a line of related species, the more clearly you understand the tragedy of what we’re doing to Earth, the consequences of depleting the planet we like to claim we’ve inherited.” – Verlyn Klinkenborg, “What Were Dinosaurs For?”

Tetman Callis 0 Comments 7:12 am

“From a long view of the history of mankind—seen from, say, ten thousand years from now—there can be little doubt that the most significant event of the 19th century will be judged as Maxwell’s discovery of the laws of electrodynamics. The American Civil War will pale into provincial insignificance in comparison with this important scientific event of the same decade.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. II

Tetman Callis 0 Comments 6:10 am

“The retina is, in fact, the brain: in the development of the embryo, a piece of the brain comes out in front, and long fibers grow back, connecting the eyes to the brain. The retina is organized in just the way the brain is organized and, as someone has beautifully put it, ‘The brain has developed a way to look out upon the world.’ The eye is a piece of brain that is touching light, so to speak, on the outside.” – Richard P. Feynman, The Feynman Lectures on Physics, Vol. I