"Coming out of space and incident on the high atmosphere, there is a thin rain of charged particles known as the primary cosmic radiation." (Cecil Powell, "The Cosmic Radiation", [Nobel lecture] 1950)
"For the investigation of the cosmic radiation, it is necessary to solve two principal technical problems: First, to detect the radiation, to determine the masses, energy and transformation properties of the particles of which it is composed, and to study the nuclear transmutations which they produce. Second, to develop methods of making such observations throughout the atmosphere and at depths underground." (Cecil Powell, "The Cosmic Radiation", [Nobel lecture] 1950)
"Today the study of the cosmic radiation is, in essence, the study of nuclear physics of the extreme high-energy region. Although the number of in coming particles is very small in comparison with those which are produced by the great machines, most of them are much more energetic than any which we can yet generate artificially; and in nuclear collisions they produce effects which cannot be simulated in the laboratory. The study of the resulting transmutations is therefore complementary to that which can be made at lower energies with the aid of the cyclotrons and synchrotrons." (Cecil Powell, "The Cosmic Radiation", [Nobel lecture] 1950) [more quotes]
"It seemed equally obvious also at that time that a prerequisite to a success full experimental attack on the nucleus was the development of means of accelerating charged particles to high velocities - to energies measured in millions of electron volts, a task which appeared formidable indeed! Accordingly, I devoted considerable time and thought to the technical problem of ways and means of reaching millions of electron volts in the laboratory. The problem seemed to reduce itself to two parts, (a) the production of high voltages, and (b) the development of accelerating tubes capable of with standing such high voltages." (Ernest O Lawrence, "The evolution of the cyclotron", [Nobel lecture] 1951)
"I have not yet lost a feeling of wonder, and of delight, that this delicate motion should reside in all the things around us, revealing itself only to him who looks for it. I remember, in the winter of our first experiments, just seven years ago, looking on snow with new eyes. There the snow lay around my doorstep - great heaps of protons quietly precessing in the earth's magnetic field. To see the world for a moment as something rich and strange is the private reward of many a discovery. " (Edward M Purcell, [Nobel lecture] 1952)
"It is an old story in physics that higher resolving power leads to new effects. We remember that the magnetic moment of the nucleus was itself discovered through the hyperfine structure of lines in the visible spectrum. The nuclear resonance line in a liquid or gas can be remarkably narrow, as you have already seen. As soon as the reason for this was recognized, it became clear that the only practical limit on resolution was the inhomogeneity of the magnetic field applied to the specimen." (Edward M Purcell, [Nobel lecture] 1952)
"I am impressed by the great limitations of the human mind. How quick are we to learn, that is, to imitate what others have done or thought before. And how slow to understand, that is, to see the deeper connections. Slowest of all, however, are we in inventing new connections or even in applying old ideas in a new field." (Frits Zernike, "How I Discovered Phase Contrast", [Nobel lecture] 1953)
"Every object that we perceive appears in innumerable aspects. The concept of the object is the invariant of all these aspects. From this point of view, the present universally used system of concepts in which particles and waves appear simultaneously, can be completely justified. The latest research on nuclei and elementary particles has led us, however, to limits beyond which this system of concepts itself does not appear to suffice. The lesson to be learned from what I have told of the origin of quantum mechanics is that probable refinements of mathematical methods will not suffice to produce a satisfactory theory, but that somewhere in our doctrine is hidden a concept, unjustified by experience, which we must eliminate to open up the road." (Max Born, "The Statistical Interpretations of Quantum Mechanics", [Nobel lecture] 1954)
"It was through [Heisenberg’s classic paper on the Uncertainty Principle] that the revolutionary character of the new conception became clear. It showed that not only the determinism of classical physics must be abandoned, but also the naïve concept of reality which looked upon the particles of atomic physics as if they were very small grains of sand. At every instant a grain of sand has a definite position and velocity. This is not the case with an electron." (Max Born, "The Statistical Interpretations of Quantum Mechanics", [Nobel lecture] 1954)
"The human mind is conservative, and the scientist makes no exception from this rule. He will accept a new theory only if it stands the trial of many experimental tests." (Hermann Bondi, [Nobel lecture] 1955)
"Nobody, I suppose, could devote many years to the study of chemical kinetics without being deeply conscious of the fascination of time and change: this is something that goes outside science into poetry; but science, subject to the rigid necessity of always seeking closer approximations to the truth, itself contains many poetical elements." (Cyril Hinshelwood, [Nobel lecture] 1956)
"It is common knowledge today that in general a symmetry principle (or equivalently an invariance principle) generates a conservation law. For example, the invariance of physical laws under space displacement has as a consequence the conservation of momentum, the invariance under space rotation has as a consequence the conservation of angular momentum." (Chen-Ning Yang, "The Law of Parity Conservation and Other Symmetry Laws of Physics", [Nobel lecture] 1957)
"Nature possesses an order that one may aspire to comprehend."
"[...] nature seems to take advantage of the simple mathematical representations of the symmetry laws. When one pauses to consider the elegance and the beautiful perfection of the mathematical reasoning involved and contrast it with the complex and far-reaching physical consequences, a deep sense of respect for the power of the symmetry laws never fails to develop." (Chen-Ning Yang, "The Law of Parity Conservation and Other Symmetry Laws of Physics", [Nobel lecture] 1957)
"The progress of science has always been the result of a close interplay between our concepts of the universe and our observations on nature. The former can only evolve out of the latter and yet the latter is also conditioned greatly by the former. Thus, in our exploration of nature, the interplay between our concepts and our observations may sometimes lead to totally unexpected aspects among already familiar phenomena." (Tsung D Lee, "Weak Interactions and Nonconservation of Parity", [Nobel lecture] 1957)
"The progress of science has always been the result of a close interplay between our concepts of the universe and our observations on nature. The former can only evolve out of the latter and yet the latter is also conditioned greatly by the former. Thus, in our exploration of nature, the interplay between our concepts and our observations may sometimes lead to totally unexpected aspects among already familiar phenomena." (Tsung Dao Lee, [Nobel lecture] 1957)
"The quantum numbers that designate the states of a system are often identical with those that represent the symmetries of the system." (Chen-Ning Yang, "The Law of Parity Conservation and Other Symmetry Laws of Physics", [Nobel lecture] 1957)
"Whereas the continuous symmetries always lead to conservation laws in classical mechanics, a discrete symmetry does not. With the introduction of quantum mechanics, however, this difference between the discrete and continuous symmetries disappears. The law of right-left symmetry then leads also to a conservation law: the conservation of parity." (Chen-Ning Yang, "The Law of Parity Conservation and Other Symmetry Laws of Physics", [Nobel lecture] 1957)
"With the advent of special and general relativity, the symmetry laws gained new importance. Their connection with the dynamic laws of physics takes on a much more integrated and interdependent relationship than in classical mechanics, where logically the symmetry laws were only consequences of the dynamical laws that by chance possess the symmetries. Also in the relativity theories the realm of the symmetry laws was greatly enriched to include invariances that were by no means apparent from daily experience. Their validity rather was deduced from, or was later confirmed by complicated experimentation. Let me emphasize that the conceptual simplicity and intrinsic beauty of the symmetries that so evolve from complex experiments are for the physicists great sources of encouragement. One learns to hope that Nature possesses an order that one may aspire to comprehend."
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