Value Quotes - page 94
E = mc2 really applies only to isolated bodies at rest. In general, when you have moving bodies, or interacting bodies, energy and mass aren't proportional. E = mc2 simply doesn't apply. ...For moving bodies, the correct mass-energy equation is
E=\frac {mc^2} {\sqrt{1-\frac{v^2} {c^2}}}
where v is the velocity. For a body at rest (v=0), this becomes E = mc2. ...we must consider the special case of particles with zero mass... examples include photons, color gluons, and gravitons. If we attempt to put m = 0 and v = c in our general mass-energy equation, both the numerator and denominator on the right-hand-side vanish, and we get the nonsensical relation E = 0/0. The correct result is that the energy of a photon can take any value. ...The energy E of a photon is proportional to the frequency f of the light it represents. ...they are related by the Planck-Einstein-Schrödinger equation E = hf, where h is Plank's constant.
Frank Wilczek
The world of books is the most remarkable creation of man. Nothing else that he builds ever lasts. Monuments fall; nations perish; civilizations grow old and die out; and, after an era of darkness, new races build others. But in the world of books are volumes that have seen this happen again and again, and yet live on, still young, still as fresh as the day they were written, still telling men's hearts of the hearts of men centuries dead.
And even the books that do not last long, penetrate their own times at least, sailing farther than Ulysses even dreamed of, like ships on the seas. It is the author's part to call into being their cargoes and passengers,-living thoughts and rich bales of study and jeweled ideas. And as for the publishers, it is they who build the fleet, plan the voyage, and sail on, facing wreck, till they find every possible harbor that will value their burden.
Clarence Day