Broca's Brain - Carl Sagan [19]
One of the foundations of special relativity is the precept that no material object can travel as fast as light. This light barrier has proved annoying to many people who wish there to be no constraints on what human beings might ultimately do. But the light limit permits us to understand much of the world that was previously mysterious in a simple and elegant way. However, where Einstein taketh away, he also giveth. There are several consequences of special relativity that seem counterintuitive, contrary to our everyday experience, but that emerge in a detectable fashion when we travel close to the speed of light—a regime of velocity in which common sense has had little experience (Chapter 2). One of these consequences is that as we travel sufficiently close to the speed of light, time slows down—our wristwatches, our atomic clocks, our biological aging. Thus a space vehicle traveling very close to the speed of light could travel between any two places, no matter how distant, in any conveniently short period of time—as measured on board the spacecraft, but not as measured on the launch planets. We might therefore one day travel to the center of the Milky Way Galaxy and return in a time of a few decades measured on board the ship—although, as measured back on Earth, the elapsed time would be sixty thousand years, and very few of the friends who saw us off would be around to commemorate our return. A vague recognition of this time dilation was made in the motion picture Close Encounters of the Third Kind, although a gratuitous opinion was then injected that Einstein was probably an extraterrestrial. His insights were stunning, to be sure, but he was very human, and his life stands as an example of what, if they are sufficiently talented and courageous, human beings can accomplish.
EINSTEIN’S LAST public act was to join with Bertrand Russell and many other scientists and scholars in an unsuccessful attempt to bring about a ban on the development of nuclear weapons. He argued that nuclear weapons had changed everything except our way of thinking. In a world divided into hostile states he viewed nuclear energy as the greatest menace to the survival of the human race. “We have the choice,” he said, “to outlaw nuclear weapons or face general annihilation.… Nationalism is an infantile disease. It is the measles of mankind … Our schoolbooks glorify war and hide its horrors. They inculcate hatred in the veins of children. I would teach peace rather than war. I would inculcate love rather than hate.”
At age sixty-seven, nine years before his death in 1955, Einstein described his lifelong quest: “Out yonder there was this huge world, which exists independently of us human beings and which stands before us like a great, eternal riddle, at least partially accessible to our inspection and thinking. The contemplation of this world beckoned like a liberation … The road to this paradise was not so comfortable and alluring as the road to the religious paradise; but it has proved itself as trustworthy, and I have never regretted having chosen it.”
CHAPTER 4
IN PRAISE
OF SCIENCE AND
TECHNOLOGY
The cultivation of the mind is a kind of food
supplied for the soul of man.
MARCUS TULLIUS CICERO,
De Finibus Bonorum et Malorum,
Vol. 19 (45–44 B.C.)
To one, science is an exalted goddess;
to another it is a cow which provides him
with butter.
FRIEDRICH VON SCHILLER,
Xenien (1796)
IN THE MIDDLE of the nineteenth century, the largely self-educated British physicist Michael Faraday was visited by his monarch, Queen Victoria. Among Faraday’s many celebrated discoveries, some of obvious and immediate practical benefit, were more arcane findings in electricity and magnetism, then little more than laboratory curiosities. In the traditional dialogue between heads of state and heads of laboratories,