Perhaps one reason that Piero did not legitimate Leonardo was that he hoped to have as his heir a son who would follow family tradition and become a notary, and it was already clear, by the time Leonardo turned twelve, that he was not so inclined.
So Einstein rejected the emission theory in favor of postulating that the speed of a light beam was constant no matter how fast its source was moving. “I came to the conviction that all light should be defined by frequency and intensity alone, completely independently of whether it comes from a moving or from a stationary light source,” he told Ehrenfest.
Now Einstein had two postulates: “the principle of relativity” and this new one, which he called “the light postulate.” He defined it carefully: “Light always propagates in empty space with a definite velocity V that is independent of the state of motion of the emitting body.”38 For example, when you measure the velocity of light coming from the headlight of a train, it will always be a constant 186,000 miles per second, even if the train is rushing toward you or backing away from you.
Just as inertial mass and gravitational mass are equivalent, so too there is an equivalence, he realized, between all inertial effects, such as resistance to acceleration, and gravitational effects, such as weight. His insight was that they are both manifestations of the same structure, which we now sometimes call the inertio-gravitational field.
With his finely honed ability to see both beauty and ugliness, Leonardo was able to create a satirical combination in his grotesques. As he wrote in his notes for his treatise on painting, “If the painter wishes to see beauties that charm him, it lies within his power to create them; and if he wishes to see monstrosities that are frightful, buffoonish, or ridiculous, or pitiable, he can be lord thereof.” 20.
Take a note of them with slight strokes in a little book which you should always carry with you,” he wrote. “The positions of the people are so infinite that the memory is incapable of retaining them, which is why you should keep these sketches as your guides.” 22.
But by 1912, Einstein had come to appreciate that math could be a tool for discovering – and not merely describing – nature’s laws. Math was nature’s playbook. “The central idea of general relativity is that gravity arises from the curvature of spacetime,” says physicist James Hartle. “Gravity is geometry.
The paintings and objects were not signed; they were not intended to be works of individual expression. Most were collaborative efforts, including many of the paintings commonly attributed to Verrocchio himself. The goal was to produce a constant flow of marketable art and artifacts rather than nurture creative geniuses yearning to find outlets for their originality.20.
Europe in the fifteenth century and become such a nuisance in Milan that they were banished by a decree in 1493. In his notebooks, Leonardo mentioned a portrayal of a gypsy in a list of his drawings, and he also recorded spending 6 soldi for a fortune-teller. All of this is speculative, and that is one of the many things that make Leonardo’s works, including those with a bit of mystery, so wonderful: his fantasia is infectious.
A Benjamin Franklin Reader Benjamin Franklin: An American Life Kissinger: A Biography.
This phenomenon, called time dilation, leads to what is known as the twin paradox.
He also speculated, correctly, that summer breezes do not by themselves cool people; instead, the cooling effect comes from the increased evaporation of human perspiration caused by the breeze.
She felt at home in the lab. It was a quiet temple for individual persistence and contemplation. She could be creative and independent as she pursued a path toward her own discoveries.
His usual pragmatic instincts fell prey to sentiments he had once tried to train himself to avoid, such as bitterness, wounded pride, emotionalism, and political fervor.
But even if merely designed to amuse his patrons, they hint at something deeper, providing a glimpse into the psychological torments swirling in the psyche of the artist playing the entertainer. 39.
In addition to such topics of debate, Franklin laid out a guide for the type of conversational contributions each member could usefully make. There were twenty-four in all, and because their practicality is so revealing of Franklin’s purposeful approach, they are worth excerpting at length:.
I wish it need not have happened in my time,” said Frodo. “So do I,” said Gandalf, “and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us.
Industry and frugality,” he wrote in describing the theme of Poor Richard’s almanacs, are “the means of procuring wealth and thereby securing virtue.
Over the ensuing years, researchers would discover new forces in nature, besides electromagnetism and gravity, and also new particles. These would make Einstein’s attempts at unification all the more complex. But he would find himself less familiar with the latest data in experimental physics, and he thus would no longer have the same intuitive feel for how to wrest from nature her fundamental principles.
She had succeeded where the other technician had failed. “It was an incredible moment, and it made me think I could do science.