Nov. 24 - Clifford Will knows what it takes to put across abstruse science: a challenge. Facing a group of easily bored science writers, the articulate physicist from Washington University in St. Louis dared to prove that he could demonstrate why general relativity is important in our daily lives.
"OK," we thought, "show us." What could be more irrelevant to most people than Einstein's arcane theory of gravity as a warping of time and space?
But as Dr. Will was quick to point out, if the United States Air Force didn't take strict account of that theory in running the Global Positioning (navigation) System (GPS), the lives of air travelers, the security of nations, and to some extent the flow of world commerce would be at risk.
He summed up his talk by saying, "to know there is a practical use of relativity theory is music to my ears."
Practical use of revolutionary concepts - that idea is the hallmark of science and engineering that have shaped so much of our century's character.
This thought force (as it might be called) of creative scientists and engineers has propelled discoveries that changed forever our concept of the universe. It led to technologies that changed - mostly for the good - the lives of people everywhere.
Thoughtlessly or deliberately misused, however, these discoveries brought tragedy. They also magnified human impact on the environment to such a degree that we now are forced to take charge of our planet's well being. We can no longer leave it to the natural processes that, until this century, maintained a livable environment.
The late Karl Compton - a chairman of the Massachusetts Institute of Technology in Cambridge, Mass. - foresaw these trends in an interview with The Christian Science Monitor nearly 50 years ago. He noted then that the sciences have brought mankind within reach of prizes richer than it ever dared dream. But these are matched by the awful consequences of social failure. The prizes, he said, will go to those who can answer the challenge of today, and that challenge is a spiritual one.
Dr. Compton explained that, in his view, the 20th century will not be known as the age of the atom. Instead, it will be known as the age when the kinship of people and the desire to provide a higher standard of living for all first emerged as a worldwide ideal. This has emerged because of modern communications, rapid transportation, and the interdependence of resources.
"It is a fact that puts a heavy responsibility on the morality and character of everyone," he said. Compton then added a mid-century insight that is relevant to a world on the brink of a new century: "Whatever may be the scientific facts of immortality, still unknown, one thing is certain - every person is immortal in the sense that his influence continues forever, in the form of his achievements and the effects of his ideas and attitudes."
Certainly, that has been true of Isaac Newton and Albert Einstein. Few outside the physics community knew how far Newton's famous mechanics had fallen from grace as this century opened. It was bad enough that, by the mid-19th century, physicists had learned that Newton's dynamics of particles and forces didn't jibe with Clark Maxwell's laws of electrodynamics. Now it couldn't cope with discoveries about the behavior of atoms and the emission and absorption of light. It couldn't even calculate the orbit of the planet Mercury.
Einstein corrected some of those flaws by extending the science of mechanics into realms where Newton had not thought to tread - such as the effect of gravity and relative motion on our perception of space and time.
So here we are at the end of the 20th century, becoming increasingly dependent on the GPS navigational network that, in turn, depends on the intellectual achievements of those two scientific giants.
The GPS was originally installed for military purposes, but now it's the basis of a multibillion-dollar industry. The military uses it to guide ships, aircraft, cruise missiles, and troops. Civilians use it for precision guidance of aircraft, ships, trucks, and for many other purposes. Hikers can buy small GPS units for wilderness trekking. Geophysicists use it for precision field measurements.
The system uses a network of 24 satellites, each carrying an atomic clock, which beam signals detected by GPS receivers. Using signals from several satellites, a receiver performs a kind of electronic triangulation to locate your position - accurate within 15 meters. Newton's gravitational theory is good enough for guiding the satellites on orbit.
But, as Will points out, the key to navigational performance is precision measurement of time. GPS receivers must know the time recorded by those atomic clocks to within 50 billionths of a second.
Up where the satellites roam, gravity is weaker than it is here at Earth's surface, and the satellites are moving fast relative to Earth-bound observers. The relativistic time warp is 800 times larger than the system's margin for error. Will says the GPS would fail in 20 minutes if it did not take relativity into account. Our century is rich with examples of scientific concepts being translated into practical benefits.
Classical physics needed one other major fix, and it has been provided this century by quantum theory. Classical science can't deal with many submicroscopic effects. Now, strict predictability of cause and effect has yielded to the realization that predictability of subatomic phenomena is statistical. Only the probability of individual interactions can be calculated.
Quantum theory even holds that, as a matter of fundamental principle, there is inherent uncertainty in the measurement of such submicroscopic events. Physicists call the theory counter-intuitive, even weird. Most people find it incomprehensible. Yet its practical consequences are everywhere. The microchips in the computer on which this was typed depend on quantum phenomena. So, too, do modern telephone systems, electric power plants, factories, cars, and you name it.
Other fields have witnessed the same transition from abstract theory to practical implications For example, at the century's beginning, Charles Darwin's and Alfred Wallace's theory of biological evolution was widely accepted - but the genetic mechanisms through which it operates remained a mystery.
Now, scientists understand those mechanisms well enough to redesign organisms - including, perhaps, humans. This raises previously unthinkable ethical and moral questions of how far to go in tinkering with organic life.
Answering those questions will challenge people to think hard about their concept of life itself, of how far life can be reduced to a property of matter. Commenting on the possibility of creating organic life in the laboratory, the late Loren Eiseley, a prominent American paleontologist of the mid-century, observed:
"I do not think, if someone finally twists the key successfully in the tiniest and most humble house of life, that many of [the basic] questions will be answered.
"Rather, I would say that if dead matter has reared up this curious landscape of fiddling crickets, song sparrows, and wondering men, it must be plain to the most devoted materialist that the matter of which he speaks contains amazing, if not dreadful, powers and may not impossibly be, as [Thomas] Hardy suggested, but one mask of many worn by the Great Face behind." In this era of cloned sheep and of mice that produce elephant eggs, Loren Eiseley's perception still stands.
Biology - particularly human biology - has advanced from a crude grasp of anatomy and function to an ever-deepening understanding of biochemistry and genetics. This has changed medicine from a hopeful art to a science. Knowledge of the importance of clean air and water, wholesome food, and other science-based public health measures have banished many former scourges. Knowledge of how cells and microorganisms function and of how genetics direct biological action allow medical scientists to design treatments targeted at specific disease mechanisms. Scientists still have much to learn. Today's "advanced" knowledge will likely seem crude in 2098.
Evolution itself, meanwhile, presents a different challenge. For today's scientists, the legacy of Darwin and Wallace is an imperative to develop new overarching insights that can guide wise stewardship of our planet.
The Darwin-Wallace concept is a process, not a fundamental law. It doesn't predict how a living system undergoing evolution will end up. Paleontologists see nothing inevitable in the evolution of humanity - or even of simple microbes.
However, evolution through natural selection is an overarching concept that enables biologists to make sense of the fossil record. Yet that insight into past life forms does little to reveal how the world is evolving today under the pressure of unplanned, unnatural selection imposed by human activity, such as overfishing or global warming.
This is literally a life or death matter for species threatened by those pressures. In the long run, it could even be a capital issue for humanity if mankind inadvertently trashes the naturally evolved biological system.
Already, the ecological point of no return has passed. Even if humans curb their nature-bashing ways, we cannot return to the days when, by and large, we could safely let evolution take its course. We must learn to manage the planet's living system in a sustainable manner. Our impact on the Earth is such that we can't undo it, only control it. If we are to prosper in the long term, we will need a deep understanding of the biosphere and its relation to the geophysical system with which it interacts.
In considering the scientific legacy of the 20th century, one might quote an Old Testament biblical verse (Deuteronomy 30:19): "I call heaven and earth to record this day against you, that I have set before you life and death, blessing and cursing: therefore choose life, that both thou and thy seed may live."
For 90 years, this newspaper has given editorial support to the progress of the sciences in the expectation that free exploration of the natural world will help humanity choose life.
* Robert C. Cowen has written on the natural sciences for the Monitor since 1950.