Steven J. Dick

• National Aeronautics and Space Administration

Throughout history, the definition of “class” and the construction of astronomical classification systems has been a deep scientific and philosophical problem: scientific because facts such as physical composition ideally need to be known for proper classification but often are not, philosophical because astronomers need to understand the philosoph...

Cosmos and culture have been intertwined throughout history, and even before recorded history. As the disciplines of archaeoastronomy and cultural astronomy have demonstrated, the links between the heavens and the Earth predate written records and have existed in a variety of forms over millennia. The night sky was not only inspiring but had a deep...

For 150 years meridian circles have played an essential part in the mission of the U. S. Naval Observatory (USNO) in its dual role as a naval observatory, in support of celestial navigation, and as a national observatory, improving the celestial reference frame of fundamental astronomy. Examining two 20th century USNO instruments, we depict meridia...

In Britain, embroiled in the global conflicts of the early 19th century, the Royal Observatory, Greenwich, was an established national institution, founded as it was for the perfection of discovering the longitude at sea, performing its regular astronomical observations and cataloguing the results. Additionally, Nevil Maskelyne (1732–1811), the Ast...

This chapter describes the discovery of the two moons of Mars, Phobos and Deimos, made in 1877 by Asaph Hall using the giant 26-in. refractor at the U. S. Naval Observatory. Subsequent research over the next century is briefly highlighted, most notably the secular acceleration of Phobos, leading to claims of its artificial nature. A renaissance in...

This paper examines what role anthropology has historically played in SETI, and how the two intellectual cultures of natural scientists and social scientists made contact in this field. I argue that these historical interactions bode well for beneficial mutual interactions between anthropology and SETI in the future. What has been lacking is a syst...

When in 1874 and 1882 Venus passed in front of the face of the Sun, most countries with a scientific reputation to keep or to gain made plans to observe the great event. The United States was no exception. With a 177,000 dollar Congressional appropriation for the 1874 event, and 78,000 dollars for 1882, the Americans sent out eight well-equipped ex...

Among the four operating principles of the NASA Astrobiology Roadmap, Principle 3 recognizes broad societal interest for the implications of astrobiology. Although several meetings have been convened in the past decade to discuss the implications of extraterrestrial intelligence, none have addressed the broader implications of astrobiology as now d...

The patronage of national governments has played an important role in the history of astronomy, classically in the form of national observatories. In this paper we (1) argue that the last three centuries have seen what we may call a “national observatory movement,” in that national governments during this period increasingly supported astronomical...

The recent discoveries of planets around Sun-like stars, possible primitive Martian fossil life, and conditions on Europa conducive to microbial life, render more urgent the question of the place of bioastronomy in the history of science. This paper argues that the tenets of bioastronomy constitute a biophysical cosmology, a scientific worldview th...

50 years after serious scientific research began in the field of exobiology, and 40 years after serious historical research began on the subject of extraterrestrial life, this paper identifies and examines some of the most important issues in the history, philosophy, and sociology of what is today known as astrobiology. As in the philosophy of scie...

The consequences of receipt of a dial tone or information flow from an extraterrestrial civilization are considered in light of historical analogues. It is argued that the history of science offers deeper insights than political history or anthropology, since the contact would be intellectual and not physical. Specific cases of the transmission of...

Almost exactly 1500 years ago, the Roman statesman and philosopher Boethius wrote The Consolation of Philosophy, a conversation with Lady Philosophy in which he proclaimed the superiority of a life of the mind over wealth and fame. What does Urania, the Muse of Astronomy, have to offer? Here we argue that astronomy offers us a cosmological worldvie...

The Drake Equation, a method for estimating the number of communicative civilizations in our galaxy, was a product of its time in several important ways. After a period of several decades during which the idea of life on other planets had reached a low point due to rise of the rare collision hypothesis for planet formation, by the 1950s the nebular...

Although the philosophy of science and of specific sciences such as physics, chemistry, and biology are well-developed fields with their own books and journals, the philosophy of astronomy and cosmology have received little systematic attention. It is time for coherent action in creating this new discipline. At least six categories of issues may be...

50 years after Olaf Stapledon’s landmark essay “Interplanetary Man?”, we propose the coming era of “Interstellar Humanity.” Over the next thousand years the domain of humanity will increasingly spread to the stars, a process that will alter our future in profound ways. At least three factors will in all probability drive this expansion: (1) increas...

Alfred Russel Wallace is best known for his work as a naturalist and evolutionist, and for his general interest in life on Earth, taking “life” in the broadest sense of the word to include both biology and culture. So it comes as a surprise to many to learn that he had an early interest in astronomy, remained “deeply interested” in astronomical dis...

Cosmotheology is a theology that takes into account what we know about the universe based on science. It is therefore a naturalistic theology in the tradition of religious naturalism. This chapter takes as its foundational assumption the concept that the supernatural does not exist. Following this concept, we present six principles of cosmotheology...

The Markowitz Moon camera program, originated at the U. S. Naval Observatory in Washington, D.C. in 1952 for the determination of “ephemeris” time, was transformed a few years later into one of the many programs of the International Geophysical Year (IGY). The Moon camera’s stated IGY goal was to improve geodesy—the study of the gravity field, shap...

Cooperation between the United States and France in space exploration must be seen in at least four contexts: global, national, institutional, and personal. Each of these interacting contexts is important, but none more so than the latter. No matter what the global, national, and institutional contexts, in the end it always comes down to people who...

The SETI endeavor represents a test for a fundamental shift in cosmological worldview, from the physical world to the biological universe. I define the “biological universe” as the scientific worldview that holds that life is widespread throughout the universe. This chapter is meant to be a contribution to the ongoing endeavor to understand where t...

We argue that Messaging Extraterrestrial Intelligence (METI), also known as active SETI, is an activity that should be undertaken for a variety of reasons. In this paper we begin by laying out some of more serious issues that METI raises. We present a brief history of Messaging Extraterrestrial Intelligence (METI) and the controversy surrounding it...

After briefly describing the origins of NASA in 1958, this chapter analyzes three broad themes of NASA’s mission over the last 50 years: human spaceflight; the space, Earth, and life sciences; and aeronautics. It distinguishes four eras of human spaceflight: the Apollo era, the Space Shuttle era, the International Space Station era, and the Moon/Ma...

The Biological Universe (Dick, Cambridge University Press, Cambridge, 1996) analyzed the history of the extraterrestrial life debate, documenting how scientists have assessed the chances of life beyond Earth during the twentieth century. Here I propose another option—that we may in fact live in a postbiological universe, one that has evolved beyond...

Although impact is an elusive concept, the Hubble Space Telescope has had a measurable effect on culture, not only through its imagery but also through its success in deepening our understanding of the universe and our place in it. Both science and culture would be poorer without its revelations.

For most of astronomical history, astronomers busied themselves with positional astronomy, a field known for the last two centuries as astrometry. Because it is impossible to analyze all of the developments of astrometry in a brief compass, we concentrate in this chapter on certain patterns of achievement, method, and research programs that emerge...

The modern era of the Search for Extraterrestrial Intelligence (SETI) was inaugurated some 35 years ago, with the seminal paper by Giuseppe Cocconi and Philip Morrison in 1959 (Cocconi and Morrison. Nature 184:844, 1959) and the Project Ozma search by Frank Drake in 1960. But even many SETI enthusiasts do not realize that this era of interstellar c...

The debate over the demotion of Pluto to a “dwarf planet” in Prague at the IAU General Assembly in 2006 showed that classification is far from a boring subject, and in fact opens a window on a little-known aspect of the history of astronomy over the last 400 years. How does an astronomer know when he or she has discovered a new class of astronomica...

The study of polar motion, termed “variation of latitude” at the time of its discovery in the late nineteenth century by Karl Friedrich Küstner and Seth Chandler, is of historical interest for many reasons. From a scientific viewpoint, its discovery must be seen in the context of positional astronomy, geodesy and Earth rotation studies. From an ins...

On January 16, 2004, NASA Administrator Sean O’Keefe announced his decision to cancel the Hubble Space Telescope (HST) Servicing Mission (SM4) by the Space Shuttle. SM4 was to have inserted two new instruments, the Wide Field Camera 3 and the Cosmic Origins Spectrograph, at the same time replacing the batteries and gyroscopes, extending Hubble’s li...

In early 1849, the U. S. Navy was making feverish preparations for a bold expedition to Chile. A Congressional appropriation had been secured, and hopes were high that the expedition would help solve one of the main problems in astronomy—determining the distance from the Earth to the Sun, today known as the astronomical unit. This chapter covers th...

Now that historians have completed surveys of the extraterrestrial life debate such as Dick's Plurality of Worlds and The Biological Universe, and Crowe's, The extraterrestrial life debate, 1750–1900, we can begin to study the possible lessons learned from that history. In this chapter we make that attempt in three overlapping areas: (1) the proble...

What are the implications of astrobiology for society? When one considers that astrobiology encompasses research on the origin and evolution of life, the existence of life beyond Earth, and the future of life on Earth and beyond, the scope of that deceptively simple question becomes clear. It embraces not only the religious, ethical, legal, and cul...

In this chapter we argue that imagination played an important role in making spaceflight possible, that spaceflight has had and continues to have an important effect on individuals and culture, and that the exploration of space has affected our individual and collective worldviews. Many (though not all) of the pioneers of spaceflight, notably Wernh...

In this chapter we provide an overview of the extraterrestrial life debate since 1900, drawing largely on the major histories of the subject during this period, The Biological Universe, Life on Other Worlds, and The Living Universe, as well as other published works. We outline the major components of the debate, including (1) the role of planetary...

Astrobiology must be seen in the context of cosmic evolution, the 13.7 billion-year master narrative of the universe. The idea of an evolving universe dates back only to the nineteenth century, and became a guiding principle for astronomical research only in the second half of the twentieth century. The modern synthesis in evolutionary biology hast...

Cosmic evolution has been seen as leading to two possible worldviews: a physical universe in which life is rare or unique to Earth, and a biological universe, in which the processes of cosmic evolution commonly end in life. These two worldviews now hang in the balance, in the same way that the heliocentric and geocentric worldviews were in the bala...

In the course of the eighteenth century, Charles Messier and William Herschel catalogued nebulae that comprise what we today recognize as six distinct classes of objects in the realm of the stars, as defined by their physical composition: gaseous nebulae including planetary nebulae and hot hydrogen clouds; dusty clouds delineated as dark nebulae an...

Although classification has been an important aspect of astronomy since stellar spectroscopy in the late nineteenth century, to date no comprehensive classification system has existed for all classes of objects in the universe. Here we present such a system, and lay out its foundational definitions and principles. The system consists of the Three K...

With a possible “storm” of Leonid meteors due in November 1998 or 1999, interest in the Leonids is once again at a peak. The history of the Leonids is of particular importance, not only because they are closely associated with the origins of meteor science, but also because historical observations extending back a millennium are a substantial aid i...

This chapter, written for the 50th anniversary of NASA, is an extended comparison of the Age of Discovery and the Age of Space. It attempts to place NASA in the cultural context of exploration and discovery. Though there are many political, social, and cultural components, we argue that exploration is the key to understanding the Space Age. Followi...

Even as astrobiologists search for life in the universe, scientists and philosophers alike are pondering the possibility of a deep and profound relationship between cosmology and biology. The universe appears in its very essence to be biocentric, in that the laws of nature and the physical constants are finely tuned for life, giving rise to what ha...

New discoveries in astrobiology give rise to many ethical questions. Does Mars belong to the Martians, even if the Martians are only microbes? What do we say in response to an alien message, and who speaks for Earth? How do we treat aliens, either remotely or in a “close encounter of the third kind?” These issues are only the tip of the proverbial...

This chapter argues that the plurality of worlds tradition originated with and was sustained by cosmological worldviews through the middle of the eighteenth century, was dominated for the following century by philosophical explorations, and in the late nineteenth century received its scientific foundations in modern terms. Even so, the extraterrest...

The founding of the U. S. Naval Observatory in Washington, DC, is a classic example of the role of competing political interests in early American science. President John Quincy Adams had called for a national observatory as early as 1825, but Congressional ridicule delayed action for almost two decades. The quest for such an observatory can only b...

This article documents that the world’s first time ball was erected at Portsmouth, England in 1829, preceding the well-known Greenwich time ball by more than 3 years. It furthermore establishes that the earliest time ball in North America was first dropped at the U. S. Naval Observatory in Washington, DC sometime between April 1, 1845 and September...

In this comprehensive and interdisciplinary volume, former NASA Chief Historian Steven Dick reflects on the exploration of space, astrobiology and its implications, cosmic evolution, astronomical institutions, discovering and classifying the cosmos, and the philosophy of astronomy. The unifying theme of the book is the connection between cosmos and...

Just as satellites orbit planets and planets orbit stars, so do galaxies have their own satellites and circumgalactic material orbiting them, notably in the form of smaller galaxies or their shredded debris known as rings or stellar streams. At least 59 of these galaxies orbit our Milky Way Galaxy out to about 1.5 million light years, believed to b...

Once formed, planets come in a variety of classes that astronomers have distinguished over a period of several centuries. We are partial to the class of terrestrial planets because one of them is our home. In general, a terrestrial planet is one whose constituents are rocky and therefore similar to the Earth in composition, by comparison with the g...

Like the interstellar medium, the interplanetary medium is composed of gas and dust (P 15), as well as energetic particles from the solar wind (P 16) and cosmic rays (S 30). The solar wind creates the heliosphere, a bubble within the more general interstellar wind, and while most of the material in the heliosphere emanates from the Sun itself, a sm...

Because of their mechanism of formation, planets tend to exist in systems, each bound to its central star. Although “free floaters” are known to roam interstellar space, in general planets as we know them live a social rather than a solitary life, mutually interacting not only gravitationally but also when material is exchanged between them, as in...

The Family of stellar systems ranges from binary stars to globular clusters with millions of stars. Binary stars are two stars that are gravitationally bound in a mutual orbit. They are sometimes also termed double stars, but that designation may also include stars that only appear close together in the sky. It is estimated that at least 80% of all...

The term “natural satellite” most commonly refers to a body such as the Moon orbiting a planet, but it also applies to bodies orbiting minor planets (P 11), dwarf planets (P 9), and Kuiper belt objects (P 21). As of 2018, 187 satellites are known to orbit the planets of our Solar System, as well as over 300 that orbit minor planets and four that or...

We now move into the Family of the intergalactic medium, consisting of both gas and dust. Intergalactic gas is a hot, highly rarefied plasma consisting primarily of ionized hydrogen, along with traces of other elements such as helium and oxygen. It has been detected at temperatures ranging from 300,000 to five million degrees Celsius. This so-calle...

Like planets, stars are born, but they do so in considerably more spectacular fashion and at rates highly dependent on their environment. A protostar, sometimes called an embryonic star, is a molecular cloud (S 25) undergoing gravitational contraction and accretion of gas and dust prior to initiating fusion reactions. The end of accretion and the o...

Brown dwarfs are objects intermediate in mass between planets and stars, too large to have formed as planets, too small to sustain hydrogen fusion. Although they have been called “a poor excuse for a star,” they are embraced by stellar astronomers and have even found a place in the standard stellar classification system. They range in mass from 13...

All things must be born, and for planets birth begins with a protoplanetary disk, a circumstellar disk of gas and dust that originates during star formation, when a protostar (S 1) condenses out of a molecular cloud (S 25). The central star is believed to be a T Tauri or higher mass object known as a Herbig Ae/Be star (S 2 and S 3) where planets ha...

Debris disks are residual materials observed around stars in the form of a flattened disk after planet formation has taken place. As such, this class is distinguished from protoplanetary disks, such as proplyds that exist before planet formation (P 1), and from circumstellar shells (S 16) formed by mass loss from stars later in stellar evolution.

From the intergalactic medium Family we now move to the Family of systems of galaxies, ranging from binary galaxies to clusters, superclusters, and filaments and voids, the largest gravitationally bound structures in the universe. A binary galaxy, sometimes called a double galaxy, consists of two galaxies either orbiting one another in bound orbits...

The term “subgalactic” is most often used in astronomical literature in connection with protogalaxies (G 1), in which subgalactic objects are the building blocks of galaxies as part of the “hierarchical clustering” process in the Cold Dark Matter (CDM) theory. In theory, subgalactic objects could also be failed galaxies, analogous to the failed sta...

T Tauri stars represent a very early stage in the history of a low-mass star, when the protostar (S 1) emerges from the surrounding molecular cloud (S 25), but before sustained core hydrogen burning on the main sequence of the Hertzsprung-Russell diagram (S 4). The energy is derived from gravitational collapse (as well as some deuterium burning beg...

With the class of “dwarf planet,” we come face-to-face with the heated public and scientific controversy that followed the 2006 decision by the International Astronomical Union (IAU) to “demote” Pluto and create this new class of objects. It was one of the most notorious decisions in the history of the IAU and in astronomical classification. The de...

With this class of objects, we enter the Family of the interstellar medium. The interstellar medium consists of about 99% gas and 1% dust, and the gas component consists of three main classes of objects: cool atomic clouds composed mainly of neutral hydrogen (H I); hot ionized clouds also composed mainly of hydrogen, known as H II regions (S 24) an...

In stark contrast to spiral galaxies like our own Milky Way, elliptical galaxies are almost featureless aggregations of stars distinguished by an ellipsoidal or spherical morphology. The ellipsoidal morphology was identified early on, even before these objects were realized to be external galaxies. In his classification of galaxies published in 192...

Like protoplanets (P 1) and protostars (S 1), galaxies must be born. Understanding their birth process is likewise fraught with difficulties and, even more than in astronomy’s other two Kingdoms, hampered by extreme distance. The details of galaxy formation remain one of the great unsolved problems of astrophysics, and therefore a dynamic field of...

The search for life in the universe is a major theme of astronomy and astrophysics for the next decade. Searches for technosignatures are complementary to searches for biosignatures, in that they offer an alternative path to discovery, and address the question of whether complex (i.e. technological) life exists elsewhere in the Galaxy. This approac...

Since the invention of the telescope 400 years ago, astronomers have rapidly discovered countless celestial objects. But how does one make sense of it all? Astronomer and former NASA Chief Historian Steven J. Dick brings order to this menagerie by defining 82 classes of astronomical objects, which he places in a beginner-friendly system known as "A...

The Ad Hoc Committee on SETI Nomenclature was convened at the suggestion of Frank Drake after the Decoding Alien Intelligence Workshop at the SETI Institute in March 2018. The purpose of the committee was to recommend standardized definitions for terms, especially those that are used inconsistently in the literature and the scientific community. Th...

Cambridge Core - Planetary Science and Astrobiology - Astrobiology, Discovery, and Societal Impact - by Steven J. Dick

The search for life in the Universe, once the domain of science fiction, is now a robust research program with a well-defined roadmap, from studying the extremes of life on Earth to exploring the possible niches for life in the Solar System and discovering thousands of planets far beyond it. In addition to constituting a major scientific endeavor,...

The search for life in the Universe, once the domain of science fiction, is now a robust research program with a well-defined roadmap, from studying the extremes of life on Earth to exploring the possible niches for life in the Solar System and discovering thousands of planets far beyond it. In addition to constituting a major scientific endeavor,...

The Drake Equation, a method for estimating the number of communicative civilizations in the Milky Way galaxy, was a product of its time in several important ways. After a period of several decades during which the idea of life on other planets had reached a low point due to rise of the “rare collision” hypothesis for planet formation, by the 1950s...

In this chapter we provide an overview of the extraterrestrial life debate since 1900, drawing largely on the major histories of the subject during this period, The Biological Universe (Dick 1996), Life on Other Worlds (Dick 1998), and The Living Universe (Dick and Strick 2004), as well as other published work. We outline the major components of th...

This chapter reviews past studies on the societal impact of extraterrestrial life and offers four related ways in which history is relevant to the subject: the history of impact thus far, analogical reasoning, impact studies in other areas of science and technology, and studies on the nature of discovery and exploration. We focus particularly on th...

Abstract This paper reports recent efforts to gather experts from the humanities and social sciences along with astrobiologists to consider the cultural, societal, and psychological implications of astrobiology research and exploration. We began by convening a workshop to draft a research roadmap on astrobiology's societal implications and later fo...

Abstract Fifty years after serious scientific research began in the field of exobiology, and forty years after serious historical research began on the subject of extraterrestrial life, this paper identifies and examines some of the most important issues in the history, philosophy, and sociology of what is today known as astrobiology. As in the phi...

Astrobiology must be seen in the context of cosmic evolution, the 13.7 billion-year master narrative of the universe. The idea of an evolving universe dates back only to the 19th century, and became a guiding principle for astronomical research only in the second half of the 20th century. The modern synthesis in evolutionary biology hastened the ac...

An analysis of the discovery of 82 classes of astronomical objects reveals an extended structure of discovery, consisting of detection, interpretation and understanding, each with its own nuances and a microstructure including conceptual, technological and social roles. This is true with a remarkable degree of consistency over the last 400 years o...