Best 538 quotes in «physics quotes» category

For decades, new-energy researchers talked about the possibility of treating a magnet so that its magnetic field would continuously shake or vibrate. On rare occasions, Sweet saw this effect, called self-oscillation, occur in electric transformers. He felt it could be coaxed into doing something useful, such as producing energy. Sweet thought that if he could find the precise way to shake or disturb a magnet's force field, the field would continue to shake by itself. It would be similar to striking a bell and having the bell keep on ringing. Sweet - who said his ideas came to him in dreams - turned for inspiration to his expertise in magnets. He knew magnets could be used to produce electricity, and wanted to see if he could get power out of a magnet by something other than the standard induction process. What Sweet wanted to do was to keep the magnet still and just shake its magnetic field. This shaking, in turn, would create an electric current. One new-energy researcher compares self-oscillation to a leaf on a tree waving in a gentle breeze. While the breeze itself isn't moving back and forth, it sets the leaf into that kind of motion. Sweet thought that if cosmic energy could be captured to serve as the breeze, then the magnetic field would serve as the leaf. Sweet would just have to supply a small amount of energy to set the magnetic field in motion, and space energy would keep it moving.

For every action, there is an equal and opposite reaction.

… for it is very probable, that the motion of gravity worketh weakly, both far from the earth, and also within the earth: the former because the appetite of union of dense bodies with the earth, in respect of the distance, is more dull: the latter, because the body hath in part attained its nature when it is some depth in the earth. {Foreshadowing Isaac Newton's Universal Law of Gravitation (1687)}

For me, the most beautiful aspects of physics are not the complicated math equations or even the ability of predicting how things will happen. What attracts me to physics is what it teaches us about the bigger picture. The general philosophical lessons that are embedded in physical laws are what excite me. For example, the fact that all particles and forces get unified within string theory teaches us about the unity underlying our universe. The amazingly vast collection of solutions to equations of string theory suggests that there may be many universes besides ours. What happened before the big bang, or was there a time before big bang? The “duality symmetry” in string theory, which exchanges small spaces with large spaces, suggests that perhaps as we go back in time the universe was effectively getting bigger instead of smaller. This suggests we came from other universes. Physics teaches us deep facts about our universe and our place in it. I hope I can add a little to this beautiful story. That is my goal.

For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountain of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries.

For the moment we might very well can them DUNNOS (for Dark Unknown Nonreflective Nondetectable Objects Somewhere).

For [Wolfgang] Pauli the central problem of electrodynamics was the field concept and the existence of an elementary charge which is expressible by the fine-structure constant ... 1/137. This fundamental pure number had greatly fascinated Pauli, .... For Pauli the explanation of the number 137 was the test of a successful field theory, a test which no theory has passed up to now.

Frederick Douglass told in his Narrative how his condition as a slave became worse when his master underwent a religious conversion that allowed him to justify slavery as the punishment of the children of Ham. Mark Twain described his mother as a genuinely good person, whose soft heart pitied even Satan, but who had no doubt about the legitimacy of slavery, because in years of living in antebellum Missouri she had never heard any sermon opposing slavery, but only countless sermons preaching that slavery was God's will. With or without religion, good people can behave well and bad people can do evil; but for good people to do evil — that takes religion.

From a philosophical point of view, Leibniz's most interesting argument was that absolute space conflicted with what he called the principle of the identity of indiscernibles (PII). PII says that if two objects are indiscernible, then they are identical, i.e. they are really one and the same object. What does it mean to call two objects indiscernible? It means that no difference at all can be found between them--they have exactly the same attributes. So if PII is true, then any two genuinely distinct objects must differ in at least one of their attributes--otherwise they would be one, not two. PII is intuitively quite compelling. It certainly is not easy to find an example of two distinct objects that share all their attributes. Even two mass-produced factory goods will normally differ in innumerable ways, even if the differences cannot be detected with the naked eye. Leibniz asks us to imagine two different universes, both containing exactly the same objects. In Universe One, each object occupies a particular location in absolute space.In Universe Two, each object has been shifted to a different location in absolute space, two miles to the east (for example). There would be no way of telling these two universes apart. For we cannot observe the position of an object in absolute space, as Newton himself admitted. All we can observe are the positions of objects relative to each other, and these would remain unchanged--for all objects are shifted by the same amount. No observations or experiments could ever reveal whether we lived in universe One or Two.

From the age of 13, I was attracted to physics and mathematics. My interest in these subjects derived mostly from popular science books that I read avidly. Early on I was fascinated by theoretical physics and determined to become a theoretical physicist. I had no real idea what that meant, but it seemed incredibly exciting to spend one's life attempting to find the secrets of the universe by using one's mind.

General relativity and quantum mechanics are in the end not as incompatible as they seemed. On closer inspection, they shake hands and engage in a beautiful dialogue. The spatial relations that weave Einstein's curved space are the very interactions weaving the relations between the systems of quantum mechanics. The two become compatible and conjoined, two sides of the same coin, as soon as it is recognized that space and time are aspects of a quantum field, and quantum fields can exist without being grounded in an external space.

George Malcolm: half white, half black, with messy tousled hair, rumpled and tugged between kind of curly and extremely curly. Once, a year or so before, he'd been at our house and he'd pulled out a lock of his hair and used it to teach me about eddies and helixes. It's a circular current into a central station, he'd explained, giving me one to hold. I pulled on the spring. Nature is full of the same shapes, he said, taking me to the bathroom sink and spinning on the top and pointing out the way the water swirled down the drain. Taking me to the bookshelf and flipping open a book on weather and showing me a cyclone. Then a spiral galaxy. Pulling me back to the bathroom sink, to my glass jar of collected seashells, and pointing out the same curl in a miniature conch. See? he said, holding the seashell up to his hair. Yes! I clapped. His eyes were warm with teaching pleasure. It's galactic hair, he said, smiling. At school, George was legendary already. He was so natural at physics that one afternoon the eighth-grade science teacher had asked him to do a preview of the basics of relativity, really fast, for the class. George had stood up and done such a fine job, using a paperweight and a yardstick and the standard-issue school clock, that the teacher had pulled a twenty-dollar bill from his wallet. I'd like to be the first person to pay you for your clarity of mind, the teacher had said. George used the cash to order pizza for the class. Double pepperoni, he told me later, when I'd asked.

God is a pure mathematician!' declared British astronomer Sir James Jeans. The physical Universe does seem to be organised around elegant mathematical relationships. And one number above all others has exercised an enduring fascination for physicists: 137.0359991.... It is known as the fine-structure constant and is denoted by the Greek letter alpha (α).

Here the attention of the research workers is primarily directed to the problem of reconciling the claims of the special relativity theory with those of the quantum theory. The extraordinary advances made in this field by Dirac ... leave open the question whether it will be possible to satisfy the claims of the two theories without at the same time determining the Sommerfeld fine-structure constant.

He (Comings) has in the past performed successful energy-converting experiments, creating a ringing resonance by injecting certain frequencies into piezo-electric crystals. When the crystal was in resonance with the plenum of space, the power output rose significantly higher than the input. He concluded that, if allowed politically, such discoveries could guide humankind in building a completely clean energy infrastructure -- resonant technologies that allow us to live in harmony with the universal energy field and the Earth.

Heisenberg's uncertainty relation measures the amount by which the complementary descriptions of the electron, or other fundamental entities, overlap. Position is very much a particle property - particles can be located precisely. Waves, on the other hand, have no precise location, but they do have momentum. The more you know about the wave aspect of reality, the less you know about the particle, and vice versa. Experiments designed to detect particles always detect particles; experiments designed to detect waves always detect waves. No experiment shows the electron behaving like a wave and a particle at the same time.

He needs "space" and "time," as if this were physics and not a human relationship.

I am more often wrong than right.

Highly complex numbers like the Comma of Pythagoras, Pi and Phi (sometimes called the Golden Proportion), are known as irrational numbers. They lie deep in the structure of the physical universe, and were seen by the Egyptians as the principles controlling creation, the principles by which matter is precipitated from the cosmic mind. Today scientists recognize the Comma of Pythagoras, Pi and the Golden Proportion as well as the closely related Fibonacci sequence are universal constants that describe complex patterns in astronomy, music and physics. ... To the Egyptians these numbers were also the secret harmonies of the cosmos and they incorporated them as rhythms and proportions in the construction of their pyramids and temples.

His laws changed all of physics and astronomy. His laws made it possible to calculate the mass of the sun and planets. The way it's done is immensely beautiful. If you know the orbital period of any planet, say, Jupiter or the Earth and you know its distance to the Sun; you can calculate the mass of the Sun. Doesn't this sound like magic? We can carry this one step further - if you know the orbital period of one of Jupiter's bright moons, discovered by Galileo in 1609, and you know the distance between Jupiter and that moon, you can calculate the mass of Jupiter. Therefore, if you know the orbital period of the moon around the Earth (it's 27.32 days), and you know the mean distance between the Earth and the moon (it's about 200,039 miles), then you can calculate to a high degree of accuracy the mass of the Earth. … But Newton's laws reach far beyond our solar system. They dictate and explain the motion of stars, binary stars, star clusters, galaxies and even clusters of galaxies. And Newton's laws deserve credit for the 20th century discovery of what we call dark matter. His laws are beautiful. Breathtakingly simple and incredibly powerful at the same time. They explain so much and the range of phenomena they clarify is mind boggling. By bringing together the physics of motion, of interaction between objects and of planetary movements, Newton brought a new kind of order to astronomical measurements, showing how, what had been a jumble of confused observations made through the centuries were all interconnected.

I am an atheist.

...I am not, however, militant in my atheism. The great English theoretical physicist Paul Dirac is a militant atheist. I suppose he is interested in arguing about the existence of God. I am not. It was once quipped that there is no God and Dirac is his prophet.

I am supposed to be helping her prepare for the GRE. Instead, we spend most of the time talking about color. The color of my clothes and shoes. The color of other people's clothes and shoes. The color of the sky when the sun has dipped just low enough to cause red light to bend the most and then, voilà, a sunset.

I am not religious in any sense; in fact, I consider myself an atheist.

I believe that this Nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to earth.

Ich selbst spiele nie Billard, [...],aber ich weiß, dass man den Ball hoch oder tief, rechts oder links nehmen kann; man kann den zweiten Ball voll treffen oder streifen; man kann stark oder schwach stoßen; die Fälsche stärker oder schwächer wählen; und sicher gibt es noch viele solcher Möglichkeiten. Ich kann mir nun jedes dieser Elemente beliebig abgestuft denken, so gibt es also nahezu unendlich viele Kombinationsmöglichkeiten. Wollte ich sie theoretisch ermitteln, so müßte ich außer den Gesetzen der Mathematik und der Mechanik starrer Körper auch die der Elastizitätslehre berücksichtigen; ich müßte die Koeffizienten des Materials kennen; den Temperatureinfluß; ich müßte die feinsten Maßmethoden für die Koordination und Abstufung meiner motorischen Impulse besitzen; meine Distanzschätzung müßte genau wie ein Nonius sein; mein kombinatorisches Vermögen schneller und sicherer als ein Rechenschieber; zu schweigen von der Fehlerrechnung, die Streungsbreite und dem Umstand, daß das zu erreichende Ziel der richtigen Koinzidenz der beiden Bälle selbst kein eindeutiges ist, sondern eine um einen Mittelwert gelagerte Gruppe von eben noch genügenden Tatbeständen darstellt.

If and when all the laws governing physical phenomena are finally discovered, and all the empirical constants occurring in these laws are finally expressed through the four independent basic constants, we will be able to say that physical science has reached its end, that no excitement is left in further explorations, and that all that remains to a physicist is either tedious work on minor details or the self-educational study and adoration of the magnificence of the completed system. At that stage physical science will enter from the epoch of Columbus and Magellan into the epoch of the National Geographic Magazine!

If all astronomical processes cease, how will the passage of time manifest itself? It is doubtful if vacuum fluctuations can provide a clock for the recording of time. Will time itself come to a stop? Is this a meaningful question? Such questions are difficult to answer.

If antimatter and matter make contact, both are destroyed instantly. Physicists call the process ‘annihilation.

I don't believe any scientific field to be superior to another.

I find the idea quite intolerable that an electron exposed to radiation should choose of its own free will not only its moment to jump off but its direction. In that case I would rather be a cobbler, or even an employee in a gaming house, than a physicist.

I forget if it was the Mathematician of Alexandria who said that geometry is beauty laid bare or the Father of Relativity who made the claim for physics,” Darger said. “She is, in either case, ravishing.

If magic violates the fundamental laws of nature, they clearly weren't all that fundamental.

If the deep logic of what determines the value of the fine-structure constant also played a significant role in our understanding of all the physical processes in which the fine-structure constant enters, then we would be stymied. Fortunately, we do not need to know everything before we can know something.

If someone tells you that something is impossible and you believe them, you should probably not be a researcher.

I have led an extraordinary life on this planet, while at the same time travelling across the universe by using my mind and the laws of physics. I have been to the furthest reaches of our galaxy, travelled into a black hole and gone back to the beginning of time. On Earth, I have experienced highs and lows, turbulence and peace, success and suffering. I have been rich and poor, I have been able-bodied and disabled. I have been praised and criticised, but never ignored. I have been enormously privileged, through my work, in being able to contribute to our understanding of the universe. But it would be an empty universe indeed if it were not for the people I love, and who love me. Without them, the wonder of it all would be lost on me. And at the end of all this, the fact that we humans, who are ourselves mere collections of fundamental particles of nature, have been able to come to an understanding of the laws governing us, and our universe, is a great triumph. I want to share my excitement about these big questions and my enthusiasm about this quest.

If these d'Herelle bodies were really genes, fundamentally like our chromosome genes, they would give us an utterly new angle from which to attack the gene problem. They are filterable, to some extent isolable, can be handled in test-tubes, and their properties, as shown by their effects on the bacteria, can then be studied after treatment. It would be very rash to call these bodies genes, and yet at present we must confess that there is no distinction known between the genes and them. Hence we can not categorically deny that perhaps we may be able to grind genes in a mortar and cook them in a beaker after all. Must we geneticists become bacteriologists, physiological chemists and physicists, simultaneously with being zoologists and botanists? Let us hope so.

If we ascribe the ejection of the proton to a Compton recoil from a quantum of 52 x 106 electron volts, then the nitrogen recoil atom arising by a similar process should have an energy not greater than about 400,000 volts, should produce not more than about 10,000 ions, and have a range in the air at N.T.P. of about 1-3mm. Actually, some of the recoil atoms in nitrogen produce at least 30,000 ions. In collaboration with Dr. Feather, I have observed the recoil atoms in an expansion chamber, and their range, estimated visually, was sometimes as much as 3mm. at N.T.P. These results, and others I have obtained in the course of the work, are very difficult to explain on the assumption that the radiation from beryllium is a quantum radiation, if energy and momentum are to be conserved in the collisions. The difficulties disappear, however, if it be assumed that the radiation consists of particles of mass 1 and charge 0, or neutrons. The capture of the a-particle by the Be9 nucleus may be supposed to result in the formation of a C12 nucleus and the emission of the neutron. From the energy relations of this process the velocity of the neutron emitted in the forward direction may well be about 3 x 109 cm. per sec. The collisions of this neutron with the atoms through which it passes give rise to the recoil atoms, and the observed energies of the recoil atoms are in fair agreement with this view. Moreover, I have observed that the protons ejected from hydrogen by the radiation emitted in the opposite direction to that of the exciting a-particle appear to have a much smaller range than those ejected by the forward radiation. This again receives a simple explanation on the neutron hypothesis.

If you see an antimatter version of yourself running towards you, think twice before embracing.

If you want to win this argument with Dad, look in chapter two of the first book of the Feynman Lectures on Physics. There's a quote there about how philosophers say a great deal about what science absolutely requires, and it is all wrong, because the only rule in science is that the final arbiter is observation - that you just have to look at the world and report what you see. Um... off the top of my head I can't think of where to find something about how it's an ideal of science to settle things by experiment instead of arguments -

I have been able to solve a few problems of mathematical physics on which the greatest mathematicians since Euler have struggled in vain ... But the pride I might have held in my conclusions was perceptibly lessened by the fact that I knew that the solution of these problems had almost always come to me as the gradual generalization of favorable examples, by a series of fortunate conjectures, after many errors. I am fain to compare myself with a wanderer on the mountains who, not knowing the path, climbs slowly and painfully upwards and often has to retrace his steps because he can go no further—then, whether by taking thought or from luck, discovers a new track that leads him on a little till at length when he reaches the summit he finds to his shame that there is a royal road by which he might have ascended, had he only the wits to find the right approach to it. In my works, I naturally said nothing about my mistake to the reader, but only described the made track by which he may now reach the same heights without difficulty.

I introduce the subject of fine structure with a mini-calendar of events. ... Winter 1914-15. Sommerfeld computes relativistic orbits for hydrogen-like atoms. Pashcen, aware of these studies, carefully investigates fine structures, .... January 6, 1916. Sommerfeld announces his fine structure formula, citing results to be published by Paschen in support of his answer. February 1916. Einstein to Sommerfeld: "A revelation!" March 1916. Bohr to Sommerfeld: "I do not believe ever to have read anything with more joy than your beautiful work." September 1916. Paschen publishes his work, acknowledging Sommerfeld's "indefatigable efforts.

If the universe is movement, it will not be in one direction only. We think of our lives as linear but it is the spin of the earth that allows us to observe time. Walk with me.

If you can fathom quantum mechanics without getting dizzy, you don't get it Et kvantebitte spring nærmere supercomputeren

If you were standing in the path of the beam, you would obviously die pretty quickly. You wouldn't really die of anything, in the traditional sense. You would just stop being biology and start being physics.

I could use the fresh air. I think that put my brain to sleep.” She pointed at the text as if it was a piece of rotten meat. “Physics?” I said. “You must need a more advanced text.” “No, it’s just boring.” I picked the book up and double checked the title, to make sure I hadn’t misidentified the subject. “Boring?” I said. “How can physics be …?” I looked up to see she’d already left the room. Simon pointed at the text, grinned and faked a yawn. “Hold on,” I said, striding after her. “Physics is not boring. Maybe you just need me to explain it better. Chloe? Chloe!

I'll never understand. Advanced physics is about describing things you can't know intuitively, so you describe it in numbers, but I've got it in front of me." He was looking around the room rather than at her. He seemed to like it, and since coming in, had eased closer to the burners. "It's like listening to blind people with no sense of touch prove atom by atom the existence and possible features of an elephant when I'm not even very interested in elephants.

In a nice little house in Atro City there lived a man called Doktor Gleichstein. He was a kind of scientist, and he was very good at his job, which is why he always worked from home. He looked a little funny because he kept losing his eyebrows. Quantum Physics, is sort of like ordinary Physics, only you tend to spend a lot more time looking for the cat. He worked in the sitting room because he’d blown the garage up once already. Apparently a lot of things happened by accident in Quantum Physics.

[In high school] my interests outside my academic work were debating, tennis, and to a lesser extent, acting. I became intensely interested in astronomy and devoured the popular works of astronomers such as Sir Arthur Eddington and Sir James Jeans, from which I learnt that a knowledge of mathematics and physics was essential to the pursuit of astronomy. This increased my fondness for those subjects.

In conclusion, I return to Einstein. If we find a planet in the Alpha Centauri system, its image, captured by a camera travelling at a fifth of light speed, will be slightly distorted due to the effects of special relativity. It would be the first time a spacecraft has flown fast enough to see such effects. In fact, Einstein’s theory is central to the whole mission. Without it we would have neither lasers nor the ability to perform the calculations necessary for guidance, imaging and data transmission over twenty-five trillion miles at a fifth of light speed. We can see a pathway between that sixteen-year-old boy dreaming of riding on a light beam and our own dream, which we are planning to turn into a reality, of riding our own light beam to the stars. We are standing at the threshold of a new era. Human colonisation on other planets is no longer science fiction. It can be science fact. The human race has existed as a separate species for about two million years. Civilisation began about 10,000 years ago, and the rate of development has been steadily increasing. If humanity is to continue for another million years, our future lies in boldly going where no one else has gone before. I hope for the best. I have to. We have no other option.