Cosmic Connection (8 page)

These realizations of the Copernican and Darwinian revolutions are profound–and, to some, disturbing. But they bring with them compensatory insights. We realize our deep connectedness with other life forms, both simple and complex. We know that the atoms that make us up were synthesized in the interiors of previous generations of dying stars. We are aware of our deep connection, both in form and in matter, with the rest of the universe. The cosmos revealed to us by the new advances in astronomy and biology is far grander and more awesome than the tidy world of our ancestors. And we are becoming a part of it, the cosmos as it is, not the cosmos of our desires.

Mankind now stands at several historical branching points. We are on the threshold of a preliminary reconnaissance of the cosmos. For the first time in his history, Man is capable of sending his instruments and himself from his home planet to explore the universe around him.

But the exploration of space has been defended largely in terms of narrow considerations of national prestige, both in the United States and in the Soviet Union; in terms of the development of technological capabilities, in an age when many people are finding the development of technology for its own sake to have disastrous consequences; in terms of technological “spinoff” when the space program costs very much more than the cost of direct development of the spinoff; and in terms of a quite tenuous argument for military advantage, in a time when people the world over long for a demilitarization of society.

Under these circumstances, it is not surprising that hard questions are being asked about expenditures in space, when there are visible and urgent needs for funds to correct injustices and improve society and the quality of life on Earth. These questions are entirely appropriate. If scientists cannot give to the man on the street a satisfactory explanation of expenditures in the exploration of space, it is not obvious that public funds should be allocated for such ventures.

The interest of an individual scientist in space exploration is likely to be very personal–something puzzles him, intrigues him, has implications that excite him. But we cannot ask the public to spend large sums just to satisfy the scientist’s curiosity. When we probe more deeply into the professional interests of individual scientists, however, we often find a focus of concern that largely overlaps the public interest.

A fundamental area of common interest is the problem of perspective. The exploration of space permits us to see our planet and ourselves in a new light. We are like linguists on an isolated island where only one language is spoken. We can construct general theories of language, but we have only one example to examine. It is unlikely that our understanding of language will have the generality that a mature science of human linguistics requires.

There are many branches of science where our knowledge is similarly provincial and parochial, restricted to a single example among a vast multitude of possible cases. Only by examining the range of cases available elsewhere can a broad and general science be devised.

The science that has by far the most to gain from planetary exploration is biology. In a very fundamental sense, biologists have been studying only one form of life on Earth. Despite the apparent diversity of terrestrial life forms, they are identical in the deepest sense. Beagles and begonias, bacteria and baleen whales all use nucleic acids for storage and transmission of hereditary information. They all use proteins for catalysis and control. All organisms on Earth, so far as we know, use the same genetic code. The cross-sectional structures of human sperm cells are almost identical with those of the cilia of paramecia. Chlorophyll and hemoglobin and the substances responsible for the coloring of many animals are all essentially the same molecule.

It is difficult to escape the conclusion–which, in a sense, is implicit in Darwinian natural selection–that all life on Earth has evolved from a single instance of the origin of life. If this is true, there is an important sense in which the biologist cannot distinguish the necessary from the contingent, that is, distinguish those aspects of life that any organism anywhere in the universe must have simply in order to be alive, from those aspects of life that are the results of the tortuous evolution by small opportunistic adaptations.

The production of simple organic (carbon-based) molecules under simulated primitive planetary conditions is now subject to active laboratory investigation. As we saw earlier, the molecules of which we are made can be produced rather easily, in the absence of life, under quite general primitive planetary conditions. But it is not practicable to perform laboratory experiments on even the early stages of biological evolution: The time scales are too long. It is only by examining living systems elsewhere that biologists can determine what other possibilities there are.

It is for this reason that the discovery of even an extremely simple organism on Mars would have profound biological significance. On the other hand, if Mars proves to be lifeless, a natural experiment has been performed for us: Two planets, in many respects similar; but on one life has evolved, on the other it has not. By comparing the experimental with the control planet, much may be discovered about the origin of life. Similarly, the search for prebiological organic chemicals on the Moon, on Mars, or on Jupiter is of great importance in understanding the steps leading to the origin of life.

As another example of the perspective provided by planetary studies, consider meteorology. The problems of turbulent flow and fluid dynamics are among the most difficult in all of physics. Some insights into the Earth’s weather have been obtained by standing back and examining, by photography from meteorological satellites, the circulation of the Earth’s atmosphere. Still, meteorological theory for the Earth is today capable of long-range weather predictions, but only over very large geographical areas, for a range of simplifying assumptions, and for only a little time into the future. Laboratory studies of atmospheric circulation have a limited scope; classically, they are performed in modified dishpans.

It would be nice to do a “Joshua” experiment, stopping the Earth from turning for a while. The change in circulation would provide insights into the role of the Earth’s rotation (particularly through Coriolis forces) in determining the circulation. But such an experiment is technologically very difficult. It also has undesirable side-effects. On the other hand, the planet Venus, with approximately the same mass and radius as Earth, has a rotation rate 240 times slower–so slow that Coriolis forces will be minor. The atmosphere is much thicker on Venus than on Earth. Nature has arranged a natural experiment for the meteorologists.

Jupiter rotates about once every ten hours; here is an enormous planet that turns faster than Earth does. The effects of rotation should be much more important than on Earth, and, indeed, Jupiter gives the impression of having a seething, roiling, turbulent atmosphere; its prominent atmospheric bands and belts are almost certainly related to the rapid rotation. Nature has arranged two comparison experiments–two planets with massive atmospheres, one rotating slowly, the other rapidly. An understanding of the circulation of the massive atmospheres of Venus and Jupiter will improve our understanding of oceanic, as well as atmospheric, circulation on Earth.

Or consider the planet Mars. Here is a planet with–quite remarkably–the same period of rotation and the same inclination of its axis of rotation to its orbital plane as Earth. But its atmosphere is only 1 percent of ours, and it has no oceans and no liquid water. Mars is a control experiment on the influence of oceans and liquid water on atmospheric circulation.

Until recently, the geologist has been restricted to one object of study, the Earth. He was unable to decide which properties of the Earth are fundamental to all planetary surfaces and which are peculiar to the unique circumstances of Earth. For example, seismographic observations of earthquakes have revealed the interior structure of Earth and its division into crust, mantle, liquid metal core, and solid inner core. But the reason Earth is so divided remains largely obscure. Was Earth’s crust exuded from the mantle through geological time? Did it fall from the skies in an early catastrophic event? Has Earth’s core formed gradually through geological time by the sinking of iron through the mantle? Or did it form discontinuously, perhaps in a molten Earth at the time of the origin of our planet? Such questions can be examined by performing seismometric observations on the surfaces of other planets; they could be relatively inexpensive experiments performed automatically by existing instrumentation.

There is now reasonably convincing evidence of continental drift. The motion of Africa and South America away from each other is the best-known example. In some theories, the driving force of continental drift and of the evolution of the interior of our planet are connected–for example, through convection currents circulating slowly between core and crust in the mantle. Such connections between surface geology and planetary interiors are just beginning to emerge in the study of other planets. We test our understanding of such connections by testing whether they apply elsewhere.

The perspectives gained in studies like these have a range of practical consequences. A generalization of the science of meteorology may lead to great improvements in weather forecasting. It may even lead to weather modification. The study of the atmosphere of Venus has already led to the theory that a runaway “greenhouse” effect has occurred there–an unstable equilibrium in which an increase in temperature leads to an increase in the atmospheric water vapor content, leading through infrared absorption of thermal radiation from the planet to a yet further increase in surface temperature, and so on. Had Earth started out only slightly closer to the Sun than it did, preliminary theoretical estimates indicate that we might have ended up as a searing hot Venus. But we live in a time when the atmosphere of Earth is being strongly modified by the activities of Man. It is of the first importance to understand precisely what happened on Venus so that an accidental recapitulation on Earth of the runaway Venus greenhouse can be avoided.

The studies of the surfaces and interiors of the planets may be of great practical benefit in earthquake prediction and in remote geological prospecting for minerals of value on Earth.

The revolution in biology that the discovery of indigenous life elsewhere would surely bring may have a range of unsuspected practical benefits, particularly to the extent that research in cancer and aging is now limited by ideas rather than money.

The study of the highly condensed matter in neutron stars and the enormous energy productions in the centers of galaxies and in quasars has already led to suggestions about possible modifications of the laws of physics, laws that have been deduced on Earth to explain phenomena observed on Earth.
The exploration of space will inevitably provide a wealth of practical benefits. But the history of science suggests that the most important of these will be unexpected–benefits we are today not wise enough to anticipate.

D
irect scientific interest in space exploration and the practical consequences that can be imagined flowing from them are not the principal or even the most general interests that space exploration holds for the layman. There is today–in a time when old beliefs are withering–a kind of philosophical hunger, a need to know who we are and how we got here. There is an ongoing search, often unconscious, for a cosmic perspective for humanity. This can be seen in innumerable ways, but most clearly on the college campus. There, an enormous interest is apparent in a range of pseudoscientific or borderline-scientific topics–astrology, Scientology, the study of unidentified flying objects, investigation of the works of Immanuel Velikovsky, and even science-fiction superheroes–all of which represent an attempt, overwhelmingly unsuccessful in my view, to provide a cosmic perspective for mankind. Professor George Wald, of Harvard, is thinking of this longing for a cosmic perspective when he writes: “We have desperately to find our way back to human values. I would even say to religion. There is nothing supernatural, in my mind. Nature is my religion, and it’s enough for me… What I mean is: We need some widely shared view of the place of Man in the Universe.”

The most widely sold book in college communities from Cambridge, Massachusetts, to Berkeley, California, in recent years was called
The Whole Earth Catalog
, which viewed itself as providing access to tools for the creation of cultural alternatives. What was striking was the number of works displayed in the
Catalog
that related to a scientific cosmic perspective. They ranged from the Hubble
Atlas of Galaxies
to flags and posters of Earth photography near full phase. The title of
The Whole Earth Catalog
derives from its founder’s urge to see a photograph of our planet as a whole. The Fall 1970 issue expanded this perspective, showing a photograph of the whole Milky Way Galaxy.