Cosmic Connection (24 page)

Astrology has not attempted to keep pace with the times. Even the calculations of planetary motions and positions performed by most astrologers are usually inaccurate.

No study shows a statistically significant success rate in predicting through their horoscopes the futures or the personality traits of newborn children. There is no field of radio-astrology or X-ray astrology or gamma-ray astrology, taking account of the energetic new astronomical sources discovered in recent years.

Nevertheless, astrology remains immensely popular everywhere. There are at least ten times more astrologers than astronomers. A large number, perhaps a majority, of newspapers in the United States have daily columns on astrology.

Many bright and socially committed young people have more than a passing interest in astrology. It satisfies an almost unspoken need to feel a significance for human beings in a vast and awesome cosmos, to believe that we are in some way hooked up with the universe–an ideal of many drug and religious experiences, the
samadhi
of some Eastern religions.

The great insights of modern astronomy have shown that, in some senses quite different from those imagined by the earlier astrologers, we
are
connected up with the universe.

The first scientists and philosophers–Aristotle, for example–imagined that the heavens were made of a different sort of material than the Earth, a special kind of celestial stuff, pure and undefiled. We now know that this is not the case. Pieces of the asteroid belt called meteorites; samples of the Moon returned by Apollo astronauts and Soviet unmanned spacecraft; the solar wind, which expands outward past our planet from the Sun; and the cosmic rays, which are probably generated from exploding stars and their remnants–all show the presence of the same atoms we know here on Earth. Astronomical spectroscopy is able to determine the chemical composition of collections of stars billions of light-years away. The entire universe is made of familiar stuff. The same atoms and molecules occur at enormous distances from Earth as occur here within our Solar System.

These studies have yielded a remarkable conclusion. Not only is the universe made everywhere of the same atoms, but the atoms, roughly speaking, are present everywhere in approximately the same proportions.

Almost all the stuff of the stars and the interstellar matter between the stars is hydrogen and helium, the two simplest atoms. All other atoms are impurities, trace constituents. This is also true for the massive outer planets of our Solar System, like Jupiter. But it is not true for the comparatively tiny hunks of rock and metal in the inner part of the Solar System, like our planet Earth. This is because the small terrestrial planets have gravities too weak to hold their original hydrogen and helium atmospheres, which have slowly leaked away to space.

The next most abundant atoms in the universe turn out to be oxygen, carbon, nitrogen, and neon. These are atoms everyone has heard of. Why are the cosmically most abundant elements those that are reasonably common on Earth–rather than, say, yttrium or praseodymium?

The theory of the evolution of stars is sufficiently advanced that astronomers are able to understand the various kinds of stars and their relations–how a star is born from the interstellar gas and dust, how it shines and evolves by thermonuclear reactions in its hot interior, and how it dies. These thermonuclear reactions are of the same sort as the reactions that underlie thermonuclear weapons (hydrogen bombs): The conversion of four atoms of hydrogen into one of helium.

But in the later stages of stellar evolution, higher temperatures are reached in the insides of stars, and elements heavier than helium are generated by thermonuclear processes. Nuclear astrophysics indicates that the most abundant atoms produced in such hot red giant stars are precisely the most abundant atoms on Earth and elsewhere in the universe. The heavy atoms generated in the insides of red giants are spewed out into the interstellar medium, by slow leakage from the star’s atmosphere like our own solar wind, or by mighty stellar explosions, some of which can make a star a billion times brighter than our Sun.

Recent infrared spectroscopy of hot stars has discovered that they are blowing off silicates into space–rock powder spewed out into the interstellar medium. Carbon stars probably expel graphite particles into surrounding cosmic space. Other stars shed ice. In their early histories, stars like the Sun probably propelled large quantities’ of organic compounds into interstellar space; indeed, simple organic molecules are found by radio astronomical methods to be filling the space between the stars. The brightest planetary nebula known (a planetary nebula is an expanding cloud usually surrounding an exploding star called a nova) seems to contain particles of magnesium carbonate: Dolomite, the stuff of the European mountains of the same name, expelled by a star into interstellar space.

These heavy atoms–carbon, nitrogen, oxygen, silicon, and the rest–then float about in the interstellar medium until, at some later time, a local gravitational condensation occurs and a new sun and new planets are formed. This secondgeneration solar system is enriched in heavy elements.

The fate of individual human beings may not now be connected in a deep way with the rest of the universe, but the matter out of which each of us is made is intimately tied to processes that occurred immense intervals of time and enormous distances in space away from us. Our Sun is a second- or thirdgeneration star. All of the rocky and metallic material we stand on, the iron in our blood, the calcium in our teeth, the carbon in our genes were produced billions of years ago in the interior of a red giant star. We are made of star-stuff.

Our atomic and molecular connection with the rest of the universe is a real and unfanciful cosmic hookup. As we explore our surroundings by telescope and space vehicle, other hookups may emerge. There may be a network of intercommunicating extraterrestrial civilizations to which we may link up tomorrow, for all we know. The undelivered promise of astrology–that the stars impel our individual characters–will not be satisfied by modern astronomy. But the deep human need to seek and understand our connection with the universe is a goal well within our grasp.

T
housands of years ago, the idea that the planets were populated by intelligent beings was uncommon. The idea was that the planets themselves were intelligent beings. Mars was the god of war, Venus was the goddess of beauty, Jupiter was the king of the gods.

In early Roman times a few writers, for example Lucian of Samasota, conceived that at least the Moon was a place that was populated as the Earth was. His science-fiction story describing travel to the Moon was called the “True History.” It was, of course, false.

The idea of the planets as an elegant celestial clockwork created by the Deity for the amazement and utility of men emerged in the Renaissance. In the year 1600 Giordano Bruno was burned to death at the stake, in part for uttering and publishing the heresy that there were other worlds and other beings inhabiting them.

The pendulum swung far in the other direction in subsequent centuries. Writers such as Bernard de Fontenelle, Emanuel Swedenborg, and even Immanuel Kant and Johannes Kepler could safely imagine that perhaps all the planets were inhabited. Indeed, the idea was expressed that the name of the planet gave some hint to the character of its inhabitants. The denizens of Venus were amorous; those of Mars, warlike or martial; the inhabitants of Mercury, fickle or mercurial; those of Jupiter, jolly or jovial. And so on. The great British astronomer William Herschel even supposed that the Sun was inhabited.

But as the extremes of the physical environments in the Solar System became clearer and the exquisite adaptation to the environment of organisms on Earth became more apparent, skeptics arose. Perhaps Mars and Venus were inhabited, but surely not Mercury, not the Moon, not Jupiter. And so on.

In the last few decades of the nineteenth century the observations of the planet Mars by Giovanni Schiaparelli and Percival Lowell quickened public excitement about the possibility of intelligence on our planetary neighbor. Lowell’s passion for the idea of intelligent beings on Mars, his articulateness, and the wide publication of his books did much to bring this idea to the public attention, as did sciencefiction writers who followed the Lowellian scenario.

But as the evidence for intelligent life on Mars withered, and as the environment of Mars was perceived to be more and more inclement by terrestrial standards, popular enthusiasm for the idea waned.

By then, scientific interest in extraterrestrial life had reached a nadir. The very enthusiasm with which Lowell pursued the idea of intelligent beings on Mars and the attention that these ideas received from the man in the street repelled many scientists. In addition, a new astronomical field, astrophysics, the application of physics to the surfaces and interiors of stars, had achieved phenomenal success, and the brightest and most enthusiastic young astronomers went into stellar astronomy rather than planetary studies. The pendulum had swung so far that in the period just after the Second World War, there was–in all of the United States–only one astronomer doing serious physical investigations of the planets, G. P. Kuiper, then of the University of Chicago. Not only had astronomers been turned off extraterrestrial life, they had been turned off planetary studies in general.

Since 1950, the situation has slowly reversed again; the pendulum is once more swinging. The development of new measuring instruments (a by-product of World War II), at first ground-based and then, more important, space-borne, has produced a massive infusion of basic new knowledge about the physical environments of the Moon and planets. Young scientists have again been attracted to planetary studies, not only astronomers, but also geologists, chemists, physicists, and biologists. The discipline needs them all.

We now know that the building blocks for the origin of life are in the cards of physics and chemistry; whenever standard primitive atmospheres are exposed to common energy sources, the building blocks of life on Earth drop out of the atmosphere in times of days or weeks. Organic compounds have been found in meteorites and in interstellar space. Small quantities have been found even in such an inhospitable environment as the Moon. They are suspected to exist in Jupiter, in the outer planets of the Solar System, as well as on Titan, the largest moon of Saturn. Both theory and observation now suggest that planets are a common, if not invariable, accompaniment of stars, rather than an exceedingly rare occurrence, as was fashionable to believe in the first decades of this century (see pages 192 and 193).

We now have, for the first time, the tools to make contact with civilizations on planets of other stars. It is an astonishing fact that the great one-thousand-footdiameter radio telescope of the National Astronomy and Ionosphere Center, run by Cornell University in Arecibo, Puerto Rico, would be able to communicate with an identical copy of itself anywhere in the Milky Way Galaxy. We have at our command the means to communicate not merely over distances of hundreds or thousands of light-years; we can communicate over tens of thousands of lightyears, into a volume containing hundreds of billions of stars. The hypothesis that advanced technical civilizations exist on planets of other stars is amenable to experimental testing. It has been removed from the arena of pure speculation. It is now in the arena of experiment.

Our first attempt to listen to broadcasts from extraterrestrial societies was Project Ozma. Organized by Frank Drake in 1960 at the National Radio Astronomy Observatory (NRAO), it looked at two stars at one frequency for two weeks. The results were negative. Slightly more ambitious projects are, at the time of writing, being performed at the Gorky Radiophysical Institute in the Soviet Union and at NRAO in the United States. All in all, perhaps a few hundred nearby stars will be examined at one or two frequencies. But even the most optimistic calculations on the distances to the nearest stars suggest that hundreds of thousands to millions of stars must be examined before an intelligible signal from one of them will be received. This requires a large effort covering a sizable period of time. But it is well within our resources, our abilities, and our interests.