Terry Pratchett quote: “Cats gravitate to kitchens like rocks gravitate to gravity.”

“The Golden Rule works like gravitation.”

Charles Fletcher Dole (1845–1927) Unitarian minister, speaker, and writer

Cleveland Address, reported in Bartlett's Familiar Quotations, 10th ed. 1919.

“A positive pressure produces an attractive gravitational field… Positive pressures are just sort of normal pressures and attractive gravity is normal gravity, so normal pressures produce normal gravity, but it is possible to have negative pressures, and negative pressures produce repulsive gravity, and that's the secret of what makes inflation possible.”

Alan Guth (1947) American theoretical physicist and cosmologist

Lecture 1: Inflationary Cosmology: Is Our Universe Part of a Multiverse? Part I.
The Early Universe (2012)

“It turns out that the energy of a gravitational field—any gravitational field—is negative. During inflation, as the universe gets bigger and bigger and more and more matter is created, the total energy of matter goes upward by an enormous amount. Meanwhile, however, the energy of gravity becomes more and more negative. The negative gravitational energy cancels the energy in matter, so the total energy of the system remains whatever it was when inflation started—presumably something very small. …This capability for producing matter in the universe is one crucial difference between the inflationary model and the previous model.”

Alan Guth (1947) American theoretical physicist and cosmologist

"A Universe in Your Backyard," in Third Culture: Beyond the Scientific Revolution (1996) ed. John Brockman, p. 279.

“Gradually, during the eighteenth century, physicists and philosophers had become so accustomed to Newton's law of gravitation, and to the equality of gravitational and inertial mass, that the miraculousness of it was forgotten and only an acute mind like Bessel's perceived the necessity of repeating those experiments. By the experiments of Bessel about 1830 and of Eötvös in 1909 the equality of gravitational and inertial mass has become one of the best ascertained empirical facts in physics.”

Willem de Sitter (1872–1934) Dutch cosmologist

Kosmos (1932), Above is Beginning Quote of the Last Chapter: Relativity and Modern Theories of the Universe -->

“To consult the rules of composition before making a picture is a little like consulting the law of gravitation before going for a walk.”

Edward Weston (1886–1958) American photographer

“The Gordon Equation is as close as being a physical law, like gravitation or planetary motion, as we will ever encounter in finance.”

William J. Bernstein (1948) economist

Source: The Four Pillars of Investing (2002), Chapter 2, Measuring The Beast, p. 54.

William Crookes (1832–1919) British chemist and physicist

Address to the Society for Psychical Research (1897)
Context: Popular imagination presupposes spiritual beings to be utterly independent of gravitation, while retaining shapes and proportions which gravitation originally determined, and only gravitation seems likely to maintain.
When and if spiritual beings make themselves visible either to our bodily eyes or to our inward vision, their object would be thwarted were they not to appear in a recognizable form; so that their appearance would take the shape of the body and clothing to which we have been accustomed. Materiality, form, and space, I am constrained to believe, are temporary conditions of our present existence. It is difficult to conceive the idea of a spiritual being having a body like ours, conditioned by the exact gravitating force exerted by the earth, and with organs which presuppose the need for food and necessity for the removal of waste products. It is equally difficult, hemmed in and bound round as we are by materialistic ideas, to think of intelligence, thought, and will existing without form or matter and untrammeled by gravitation or space.

“Gravitation is not only similar to inertia in its generality, it is also measured by the same number… the mass. The inertial mass is what Newton calls the "quantity of matter": it is a measure for the resistance offered by a body to a force trying to alter its state of motion. It might be called the "passive mass." The gravitational mass, on the other hand, is a measure of the force exerted by the body in attracting other bodies. We might call it the "active" mass. The equality of active and passive, or gravitational and inertial, mass was in Newton's system a most remarkable accidental co-incidence, something like a miracle. Newton himself decidedly felt it as such, and made experiments to verify it, by swinging a pendulum with a hollow bob which could be filled with different materials. The force acting on the pendulum is proportional to its gravitational mass, the inertia to its inertial mass: the period of its swing thus depends on the ratio between these two masses. The fact that the period is always the same therefore proves that the gravitational and inertial masses are equal.”

Willem de Sitter (1872–1934) Dutch cosmologist

Kosmos (1932), Above is Beginning Quote of the Last Chapter: Relativity and Modern Theories of the Universe -->

“They banish us to the kitchen, there to tell stories to the cat.”

Giovanni Boccaccio book The Decameron

Ci cacciano in cucina a dir delle favole colla gatta.
Fifth Day, Tenth Story (tr. J. M. Rigg)
The Decameron (c. 1350)

“We can deduce, often, from one part of physics like the law of gravitation, a principle which turns out to be much more valid than the derivation.”

Richard Feynman book The Character of Physical Law

Source: The Character of Physical Law (1965), chapter 2, “ The Relation of Mathematics to Physics http://www.youtube.com/watch?v=M9ZYEb0Vf8U” referring to the law of conservation of angular momentum
Context: Now we have a problem. We can deduce, often, from one part of physics like the law of gravitation, a principle which turns out to be much more valid than the derivation. This doesn't happen in mathematics, that the theorems come out in places where they're not supposed to be!

“Cats gravitate to kitchens like rocks gravitate to gravity.”

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