Scientist on Trial for Teaching Physics

After waiting patiently for the noise to subside, one of the male Red Guards turned to the victim. “Ye Zhetai, you are an expert in mechanics. You should see how strong the great unified force you’re resisting is. To remain so stubborn will lead only to your death! Today, we will continue the agenda from the last time. There’s no need to waste words. Answer the following question without your typical deceit: Between the years of 1962 and 1965, did you not decide on your own to add relat...

 Intellectual Exploration as Geographical Exploration

My own field of physics is passing today through a phase of exuberant freedom, a phase of passionate prodigality. Sometimes as I listen to the conversation of my young colleagues at Princeton, I feel as if I am lost in a rain forest, with insects and birds and flowers growing all around me in intricate profusion, growing too abundantly for my sixty-year-old brain to comprehend. But the young people are at home in the rain forest and walk confidently along trails which to me are almost invisib...

 Astronomers Inventing Planets Based on Circumstantial Evi...

It happened three times in the past that theoretical astronomers invented a new planet on the basis of indirect and circumstantial evidence. The first time was in 1845 when Adams and Leverrier independently deduced the existence of the planet Neptune from the perturbations which it had produced in the motion of Uranus. One year later, Neptune was duly discovered in the predicted region of the sky. The successful prediction of the presence of an unseen planet was one {31} of the great events...

 Gravity Travels at the Speed of Light

Here's the rub. In Newton's theory of gravity, one body exerts a gravitational pull on another with a strength determined solely by the mass of the objects involved and the magnitude of their separation. The strength has nothing to do with how long the objects have been in each other's presence. This means that if their mass or their separation should change, the objects will, according to Newton, immediately feel a change in their mutual gravitational attraction. For instance, Newton's theor...

 Natural Laws are Universal

...the order of the Universe is not an assumption; it's an observed fact. We detect the light from distant quasars only because the laws of electromagnetism are the same ten billion light years away as here. The spectra of those quasars are recognizable only because the same chemical elements are present there as here, and because the same laws of quantum mechanics apply. The motion of galaxies around one another follows familiar Newtonian gravity. Gravitational lenses and binary pulsar spin-...

 Science is the Knot Tying it all together

The creation was a concept—a connected set of concepts. There was the concept of a universal gravitation-reaching beyond the tree tops and the air to the ends of space. There was the concept of other universal forces in space, which ti to pull the moon away as a whirling stone pulls away fro: its string. And there was the concept which put an end to the four elements of Aristotle: the concept of mass, alike in t apple and the earth and the moon, in all earthly and heavenly bodies.** All t...