[This] may prove to be the beginning of some embracing generalization, which will throw light, not only on radioactive processes, but on elements in general and the Periodic Law.... Chemical homogeneity is no longer a guarantee that any supposed element is not a mixture of several of different atomic weights, or that any atomic weight is not merely a mean number.

[We are] a fragile species, still new to the earth, … here only a few moments as evolutionary time is measured, … in real danger at the moment of leaving behind only a thin layer of of our fossils, radioactive at that.

By the 18th century science had been so successful in laying bare the laws of nature that many thought there was nothing left to discover. Immutable laws prescribed the motion of every particle in the universe, exactly and forever: the task of the scientist was to elucidate the implications of those laws for any particular phenomenon of interest. Chaos gave way to a clockwork world. But the world moved on ...Today even our clocks are not made of clockwork. ... With the advent of quantum mechanics, the clockwork world has become a lottery. Fundamental events, such as the decay of a radioactive atom, are held to be determined by chance, not law.

From the aspect of energy, renewed by radio-active phenomena, material corpuscles may now be treated as transient reservoirs of concentrated power. Though never found in a state of purity, but always more or less granulated (even in light) energy nowadays represents for science the most primitive form of universal stuff.

Human civilization is but a few thousand years long. Imagine having the audacity to think that we can devise a program to store lethal radioactive materials for a period of time that is longer than all of human culture to date.

I have satisfied myself that the [cosmic] rays are not generated by the formation of new matter in space, a process which would be like water running up a hill. Nor do they come to any appreciable amount from the stars. According to my investigations the sun emits a radiation of such penetrative power that it is virtually impossible to absorb it in lead or other substances. ... This ray, which I call the primary solar ray, gives rise to a secondary radiation by impact against the cosmic dust scattered through space. It is the secondary radiation which now is commonly called the cosmic ray, and comes, of course, equally from all directions in space. [The article continues: The phenomena of radioactivity are not the result of forces within the radioactive substances but are caused by this ray emitted by the sun. If radium could be screened effectively against this ray it would cease to be radioactive, he said.]

I like people. I like animals, too—whales and quail, dinosaurs and dodos. But I like human beings especially, and I am unhappy that the pool of human germ plasm, which determines the nature of the human race, is deteriorating.
[Stating his alarm for the effect of radioactive fallout on human heredity. The article containing the quote was published three days after he was awarded the 1962 Nobel Peace Prize.]

If the world has begun with a single quantum, the notions of space and would altogether fail to have any meaning at the beginning; they would only begin to have a sensible meaning when the original quantum had been divided into a sufficient number of quanta. If this suggestion is correct, the beginning of the world happened a little before the beginning of space and time. I think that such a beginning of the world is far enough from the present order of Nature to be not at all repugnant. It may be difficult to follow up the idea in detail as we are not yet able to count the quantum packets in every case. For example, it may be that an atomic nucleus must be counted as a unique quantum, the atomic number acting as a kind of quantum number. If the future development of quantum theory happens to turn in that direction, we could conceive the beginning of the universe in the form of a unique atom, the atomic weight of which is the total mass of the universe. This highly unstable atom would divide in smaller and smaller atoms by a kind of super-radioactive process.

In Melvin Calvin’s office there were four photographs: Michael Polanyi, Joel Hildebrand, Gilbert N. Lewis, and Ernest O. Lawrence. These scientists were his mentors: Polanyi for introducing him to the chemistry of phthalocyanine; Hildebrand for bringing him to Berkeley; Lewis, perhaps his most influential teacher; and Lawrence, who provided him the opportunity to work with the new scientific tool of radioactive carbon, which enabled the search for the path of carbon in photosynthesis to be successful.

Is no one inspired by our present picture of the universe? This value of science remains unsung by singers: you are reduced to hearing not a song or poem, but an evening lecture about it. This is not yet a scientific age.
Perhaps one of the reasons for this silence is that you have to know how to read music. For instance, the scientific article may say, “The radioactive phosphorus content of the cerebrum of the rat decreases to one-half in a period of two weeks.” Now what does that mean?
It means that phosphorus that is in the brain of a rat—and also in mine, and yours—is not the same phosphorus as it was two weeks ago. It means the atoms that are in the brain are being replaced: the ones that were there before have gone away.
So what is this mind of ours: what are these atoms with consciousness? Last week’s potatoes! They now can remember what was going on in my mind a year ago—a mind which has long ago been replaced. To note that the thing I call my individuality is only a pattern or dance, that is what it means when one discovers how long it takes for the atoms of the brain to be replaced by other atoms. The atoms come into my brain, dance a dance, and then go out—there are always new atoms, but always doing the same dance, remembering what the dance was yesterday.

It was my good fortune to be linked with Mme. Curie through twenty years of sublime and unclouded friendship. I came to admire her human grandeur to an ever growing degree. Her strength, her purity of will, her austerity toward herself, her objectivity, her incorruptible judgement—all these were of a kind seldom found joined in a single individual… The greatest scientific deed of her life—proving the existence of radioactive elements and isolating them—owes its accomplishment not merely to bold intuition but to a devotion and tenacity in execution under the most extreme hardships imaginable, such as the history of experimental science has not often witnessed.

May every young scientist remember … and not fail to keep his eyes open for the possibility that an irritating failure of his apparatus to give consistent results may once or twice in a lifetime conceal an important discovery.
Commenting on the discovery of thoron gas because one of Rutherford’s students had found his measurements of the ionizing property of thorium were variable. His results even seemed to relate to whether the laboratory door was closed or open. After considering the problem, Rutherford realized a radioactive gas was emitted by thorium, which hovered close to the metal sample, adding to its radioactivity—unless it was dissipated by air drafts from an open door. (Thoron was later found to be argon.)

My experiments proved that the radiation of uranium compounds ... is an atomic property of the element of uranium. Its intensity is proportional to the quantity of uranium contained in the compound, and depends neither on conditions of chemical combination, nor on external circumstances, such as light or temperature.
... The radiation of thorium has an intensity of the same order as that of uranium, and is, as in the case of uranium, an atomic property of the element.
It was necessary at this point to find a new term to define this new property of matter manifested by the elements of uranium and thorium. I proposed the word radioactivity which has since become generally adopted; the radioactive elements have been called radio elements.

No other animals have ever lighted fires as far as we can tell. In field archeology, a charcoal deposit found in such a location that it could not have been made by a forest fire is taken as conclusive evidence of man. A circular dark disk in the soil five or six feet in diameter is such a find. … With … modern radioactive dating methods, we can trace man’s history.

One of the striking things about places heavily contaminated by radioactive nuclides is the richness of their wildlife. This is true of the land around Chernobyl, the bomb test sites of the Pacific, and areas near the United States’ Savannah River nuclear weapons plant of the Second World War. Wild plants and animals do not perceive radiation as dangerous, and any slight reduction it may cause in their lifespans is far less a hazard than is the presence of people and their pets.

Radioactive cats have 14 half lives.

Some months ago we discovered that certain light elements emit positrons under the action of alpha particles. Our latest experiments have shown a very striking fact: when an aluminium foil is irradiated on a polonium preparation [alpha ray emitter], the emission of positrons does not cease immediately when the active preparation is removed: the foil remains radioactive and the emission of radiation decays exponentially as for an ordinary radio-element. We observed the same phenomenon with boron and magnesium.
[Co-author with Irène Joliot-Curie. This one-page paper reported their discovery of artificial radioactivity for which they were awarded the 1935 Nobel Prize for Chemistry.]

Suddenly there was an enormous explosion, like a violent volcano. The nuclear reactions had led to overheating in the underground burial grounds. The explosion poured radioactive dust and materials high up into the sky. It was just the wrong weather for such a tragedy. Strong winds blew the radioactive clouds hundreds of miles away. It was difficult to gauge the extent of the disaster immediately, and no evacuation plan was put into operation right away. Many villages and towns were only ordered to evacuate when the symptoms of radiation sickness were already quite apparent. Tens of thousands of people were affected, hundreds dying, though the real figures have never been made public. The large area, where the accident happened, is still considered dangerous and is closed to the public.

That radioactive elements created by us are found in nature is an astounding event in the history of the earth. And of the Human race. To fail to consider its importance and its consequences would be a folly for which humanity would have to pay a terrible price. When public opinion has been created in the countries concerned and among all the nations, an opinion informed of the dangers involved in going on with the tests and led by the reason which this information imposes, then the statesmen may reach an agreement to stop the experiments.

The age of the earth was thus increased from a mere score of millions [of years] to a thousand millions and more, and the geologist who had before been bankrupt in time now found himself suddenly transformed into a capitalist with more millions in the bank than he knew how to dispose of … More cautious people, like myself, too cautious, perhaps, are anxious first of all to make sure that the new [radioactive] clock is not as much too fast as Lord Kelvin’s was too slow.

The century of biology upon which we are now well embarked is no matter of trivialities. It is a movement of really heroic dimensions, one of the great episodes in man’s intellectual history. The scientists who are carrying the movement forward talk in terms of nucleo-proteins, of ultracentrifuges, of biochemical genetics, of electrophoresis, of the electron microscope, of molecular morphology, of radioactive isotopes. But do not be misled by these horrendous terms, and above all do not be fooled into thinking this is mere gadgetry. This is the dependable way to seek a solution of the cancer and polio problems, the problems of rheumatism and of the heart. This is the knowledge on which we must base our solution of the population and food problems. This is the understanding of life.

The Himalayas are the crowning achievement of the Indo-Australian plate. India in the Oligocene crashed head on into Tibet, hit so hard that it not only folded and buckled the plate boundaries but also plowed into the newly created Tibetan plateau and drove the Himalayas five and a half miles into the sky. The mountains are in some trouble. India has not stopped pushing them, and they are still going up. Their height and volume are already so great they are beginning to melt in their own self-generated radioactive heat. When the climbers in 1953 planted their flags on the highest mountain, they set them in snow over the skeletons of creatures that had lived in a warm clear ocean that India, moving north, blanked out. Possibly as much as 20,000 feet below the sea floor, the skeletal remains had turned into rock. This one fact is a treatise in itself on the movements of the surface of the earth.
If by some fiat, I had to restrict all this writing to one sentence; this is the one I would choose: the summit of Mount Everest is marine limestone.

When one studies strongly radioactive substances special precautions must be taken if one wishes to be able to take delicate measurements. The various objects used in a chemical laboratory and those used in a chemical laboratory, and those which serve for experiments in physics, become radioactive in a short time and act upon photographic plates through black paper. Dust, the air of the room, and one’s clothes all become radioactive.

With an interest almost amounting to anxiety, geologists will watch the development of researches which may result in timing the strata and the phases of evolutionary advance; and may even-going still further back—give us reason to see in the discrepancy between denudative and radioactive methods, glimpses of past aeons, beyond that day of regeneration which at once ushered in our era of life, and, for all that went before, was 'a sleep and a forgetting'.