Humanity is Fortunate to Have a Variety of Energy Sources...

Humanity is fortunate in having such a variety of energy resources at its disposal. In the very long run we shall need energy that is unpolluting; we shall have sunlight. In the fairly long run we shall need energy that is inexhaustible and moderately clean; we shall have deuterium. In the short run we shall need energy that is readily usable and abundant; we shall have uranium. Right now we need energy that is cheap and convenient; we have coal and oil. Nature has been kinder to us than we h...

 The Cosmic Perspective

The cosmic perspective comes from the frontiers of science, yet it's not solely the province of the scientist. The cosmic perspective belongs to everyone. The cosmic perspective is humble. The cosmic perspective is spiritual—even redemptive—but not religious. The cosmic perspective enables us to grasp, in the same thought, the large and the small. The cosmic perspective opens our minds to extraordinary ideas but does not leave them so open that our brains spill out, making us suscepti...

 Galileo and the Altar Lamp Pendulum

IN 1583 Galileo Galilei (1564–1642), a youth of nineteen attending prayers in the baptistery of the Cathedral of Pisa, was, according to tradition, distracted by the swinging of the altar lamp. No matter how wide the swing of the lamp, it seemed that the time it took the lamp to move from one end to the other was the same. Of course Galileo had no watch, but he checked the intervals of the swing by his own pulse. This curious everyday puzzle, he said, enticed him away from the study of medi...

 Einstein's "Biggest Blunder"

For much of the modern era, scientists followed Nicolaus Copernicus, Galileo Galilei, and Isaac Newton in believing the cosmos to be eternal and unchanging. But in 1917, when Albert Einstein applied his theory of relativity to space-time as a whole, his equations implied that the universe could not be static; it must be either expanding or contracting. This struck Einstein as grotesque, so he added to his theory a fiddle factor called the "cosmological constant" that eliminated the implicatio...