The Principle of Mediocrity

An infinite universe filled with life-sustaining planets is one result of the revolution begun by Copernicus and developed by his contemporaries. There is another implication of Copernicanism that deserves attention in a study of extraterrestrial civilizations. This is the introduction of the so-called Copernican principle, or principle of mediocrity. The principle of mediocrity is a twentieth-century concept that grew out of the Copernican revolution of the sixteenth century. Although...

The Plurality of the Worlds Fontenelle

No one better represents the new attitude toward extraterrestrial life than Bernard le Bovier de Fontenelle (1657 1757), the author of Conversations on the Plurality of Worlds (1686). Originally written in French, Fontenelle's book went through thirty-three editions during the author's long life. It was translated into English, German, Danish, Dutch, Greek, Italian, Polish, Russian, Spanish, and Swedish. Fontenelle was not an original contributor to science. As secretary of the renowned French...

Exobiology

In his sophomore year at the University of Chicago, Carl Sagan studied chemistry with Nobel laureate Harold Urey. At about the same time, Urey's student Stanley Miller began his experiments on the origins of life. Miller mixed together hydrogen, methane, ammonia, and water vapor, the gases believed to compose the Earth's atmosphere at the emergence of life. He then simulated the effects of lightning by passing electrical discharges through this gaseous mixture. Miller, of course, did not create...

Rallying

Frank Drake to the contrary, the absence of either space probes or colonies convinced many that the basic premises of SETI were suspect. After all, the recently established American space program had already launched its version of space probes. Sagan, Drake, and others helped NASA attach messages to the Pioneer and Voyager spacecraft (1972 1977). IfNASA engineers could send spacecraft on interstellar journeys, why were technologically superior extraterrestrials unable to do likewise As...

Radio Astronomy

Once radio astronomy was established, it became another factor influencing mid-century thinking about extraterrestrial life. Ernest W Barnes (1874 1953), mathematician, Anglican bishop, and teacher of E. A. Milne, was one of the earliest scientists to propose radio communication with intelligent extraterrestrial beings. In a paper delivered before the British Association for the Advancement of Science in 1931, Bishop Barnes claimed that alien beings exist who are immeasurably beyond our mental...

The Eye of the Beholder

Lowell was not content to view Mars through a telescope. He wanted to photograph its canals. A photograph of the planet with the canals clearly displayed would provide the objective proof he needed to silence critics and win scientific approval for his views. Personal bias, bad eyesight, or poor draftsmanship can distort the human observer's interpretation of Mars. A camera, on the other hand, was a neutral recorder of reality. Unfortunately, at the end of the nineteenth century, it was...

Universal Science

As early as the sixth century b.c., Xenophanes criticized the Greeks for modeling their gods and goddesses after human beings. He satirically declared that if cows and horses had hands and could draw, they would model the bodies of their gods after themselves. And in the middle of the eighteenth century, the British philosopher David Hume observed there was a universal tendency among humans to conceive all beings like themselves, and to transfer to every object, those qualities, with which they...

Civilization

Civilization became a popular term in the eighteenth century when it defined a polished and refined state of society. Civilization was contrasted with barbarism or savagery, which possessed much lower levels of social organization, moral behavior, artistic sensibility, and knowledge. Many nineteenth-century anthropologists mistakenly believed that all human societies pass through a savage and barbaric stage before they reach the heights of civilized societies exemplified in Western Europe. By...

The Development of Planetary Astronomy

Huygens's Kosmotheoros was influenced by the models of the universe proposed by Copernicus and Descartes. However, eleven years before the appearance of Huygens's book, Sir Isaac Newton published his Principia (1687). The Newtonian universe, as outlined in his Principia, eventually displaced older models and stimulated the modern study of physics and astronomy, especially the investigation of planetary motion. The Newtonian universe is the picture of the cosmos many of us hold in our minds...

Interstellar Visits

Not everyone was content to leave the search for extraterrestrial intelligence in the hands of radio astronomers waiting for incoming alien signals. Scientists critical of an exclusive reliance upon radio astronomy proposed more dynamic ways of learning about extraterrestrial civilizations. Travel through interstellar space was an alternative but never a very popular one among scientists. As early as 1959, physicist John R. Pierce of the Bell Telephone Laboratories considered the relativistic...

Descartes Cosmic Model

Descartes Ateher

Wilkins strongly defended the Copernican system. However, the Sun-centered model of the universe was nearly a century old when Wilkins published his book, and Copernicus had been largely concerned with solving problems in mathematical astronomy. Some saw a need for a new model of the universe, one that embraced recent advances in the physical sciences, astronomy, and philosophy. In the mid-seventeenth century, the French thinker Ren Descartes (1596 1650) met the demand for a new cosmic model....

Technology

Seekers of extraterrestrial intelligence have adopted some mistaken notions about the nature of technology. They assume that technology moves progressively toward goals predetermined by the universal laws of science. The pathway of technological development culminates in interstellar communication by space ships, probes, or radio waves. The Project Cyclops report of 1971 argued that despite differences in intelligent life forms, their technologies converge. At some point in the history of...

Schiaparellis Canals

The claim that Martians had built irrigation canals on their planet originated in the observations of the famous Italian astronomer Giovanni V. Schiaparelli (1835 1910). As a young man, Schiaparelli studied civil engineering at the University of Turin, where he specialized in architectural and hydraulic engineering. Schiaparelli learned how to design and construct canals, dams, sewers, aqueducts, pipelines, flood control systems, and other structures associated with the flow of fluids. Despite...

Panspermia

Although scientists have learned much about how life may have developed from complex molecules on the primitive Earth, their work has barely begun. In 1966 Carl Sagan predicted that scientists would synthesize simple life forms in the laboratory within a decade. Thirty-three years later, a noted British paleobiologist, Simon Conway Morris, observed that despite decades of research into the origins of life, and frequent claims of a breakthrough, we are still paddling on the edges of an ocean of...

Drakes Equation

Telegraph System Using Dots And Dashes

The Space Science Board of the prestigious National Academy of Sciences responded positively to recent advances in the study of extraterrestrial life. It authorized a small conference on the subject at the National Radio Astronomy Observatory located at Green Bank, West Virginia. Notable scientists attended this meeting in November 1961. Attendees included Melvin Calvin, Giuseppe Cocconi, Frank Drake, John C. Lilly, Philip Morrison, Bernard Oliver, and Carl Sagan. John Lilly, a popular...

The Evolutionists on SETI

Three well-known evolutionary biologists Theodosius Dobzhansky, George Gaylord Simpson, and Ernst Mayr mounted strong attacks on notions of the origin and development of intelligent extraterrestrial life held by SETI investigators. Their criticism focused on four issues first, the deterministic thinking of scientists who portray evolution as a fixed process with preprogrammed goals second, the contingent nature of organic evolution mutations and unpredictable ecological changes make the...

The Maritime Analogy

The use of the maritime exploration analogy by Wilkins, Fontenelle, and Huygens may seem quaint or naive to modern readers. It is true that the analogy led seventeenth- and eighteenth-century thinkers to underestimate the difficulties involved in traveling to the Moon and the planets. However, comparisons between sea and space travel persisted and became part of the modern rhetoric of the space program in the mid-twentieth century. Proponents of the American space program revived the...

Huygenss Probable Conjectures

In 1656 the English scientific journalist and administrator Henry Oldenburg wrote to a friend, praising the latest developments in telescope design. If these improvements continue, he declared, we will soon be finding new countries in the heavens just as Columbus discovered new lands in America. Recent discoveries made by the young Dutch astronomer Christiaan Huygens 1629 1695 inspired Oldenburg's optimistic outlook. In 1655, using a telescope he designed, Huygens observed a satellite Titan...

Life on the moon Galileos Telescope

Galileo Galilei 1564 1642 , an Italian mathematician and philosopher, made the first systematic telescopic observation of the heavens in 1609 1610. Galileo used a twenty power instrument he had constructed in his workshop. He first aimed his new telescope at the Moon and then at the stars and planets. The results of his pioneering work appeared in Sidereus Nuncius Sidereal Messenger in 1610. This treatise, the earliest publication in modern observational astronomy, inspired European astronomers...

Origins of Life

The discovery of new galaxies, and the observational proof that the universe as a whole was expanding, forced astronomers to rethink the issue of extrasolar planets. During the fifteen-year period 1943 1958, astronomers became convinced that planetary systems and inhabited planets were not rare occurrences. Along with an expanding universe, new scientific studies of the origins of life influenced the acceptance of extraterrestrial life at midcentury. Questions about the origins of life moved...

Astroengineering and Supercivilizations

Freeman Dyson was among the few scientists who defended the feasibility of interstellar travel. In 1964 Dyson, a distinguished theoretical physicist and professor at the Princeton Institute for Advanced Studies, envisioned voyages by nuclear propelled spacecraft moving at slow speeds and lasting thousands of years. The crews of such spacecraft would be frozen, placed in cold storage, and revived when needed. Travel that extended over a millennium might not appeal to humans but, as Dyson said,...

Kepler and Galileo

Galileo sent a copy of Sidereus Nuncius to Johannes Kepler 1571 1630 soon after its publication. Kepler was an outstanding member of the new generation of Copernican astronomers. He had already transformed mathematical astronomy with his work on the shape of planetary orbits. For two thousand years, astronomers believed planets travelled along perfect circular orbits. Kepler used astronomical data gathered by the Danish astronomer Tycho Brahe to prove that the planetary paths were elliptical,...

Science Fact and Science Fiction

Kepler's Somnium inaugurated a new literary genre. This genre joined the findings of science with literary inventiveness to depict the life and society of intelligent extraterrestrial beings. Literary critics claim that Somnium is the earliest known example of science fiction. They show a line of influence extending from Kepler to the pioneering science fiction writer H. G. Wells. Wells read Somnium before writing The First Men in the Moon 1901 . Following Kepler's lead, he put his lunar...

The Infinitization of the Universe

The ancient Greek atomists were among the first to introduce the idea of an infinite universe. In the fifth century b.c., they claimed that tiny bits of matter atoms moved randomly in infinite empty space. Because an infinite number of atoms collide an infinite number of times in an infinite void, an infinite number of universes exist. Each universe has its own sun, planets, stars, and life forms. A century later the influential philosopher Aristotle 384 322 b.c. rejected the atomists' infinite...

Chapter Nine

. . . when I address the floor tomorrow . . . we will not be talking about SETI . . . we will be talking about HRMS, which is the new name by which this program continues to have life. And it will be my intention, once again, to offer an amendment which specifically deletes the funding for this program. Senator Richard Bryan, Congressional Record, September 20, 1993 The search for extraterrestrial intelligence had Russian as well as American origins. The early successes of the USSR space...

After Contact

Carl Sagan Frank Drake

Suppose members of an alien civilization retrieved a Pioneer or Voyager spacecraft and decoded its message What then What would happen after humans contacted an advanced civilization in space Scientific speculation about the consequence ofcontact with extraterrestrials was widely discussed for the first time in the twentieth century. The invention of the radio telescope and the success of space programs in the Soviet Union and the United States popularized the issue of alien contact. Humans...

Message to the Stars

Mitochondria Silhouette

Sagan began his scientific career as a planetary astronomer. His continuing interest in advanced extraterrestrial life led him into work that enhanced his popularity and soon transcended the boundaries of our solar system. In 1970 Sagan persuaded NASA to sponsor a project to send the first message to the inhabitants of interstellar space. This effort, which was part of the Pioneer 10 space mission, displayed Sagan's superb skills as a publicist for space science. There was little chance that...

Keplers Dream

Kepler was interested in the Moon and its inhabitants throughout his life as a scientist. His most elaborate description of lunar life and culture appears in Som-nium Dream , published posthumously in 1634. Itcontains his final and definitive statement on the motions, physical features, and flora and fauna of the Moon. Kepler wrote Somnium to promote the acceptance ofthe Copernican system. He intended to advance it by comparing the relative motions of the Moon and Earth and demonstrating the...