This chapter describes the thirty-seven autistic academics who share their stories in this book. In a different world they would be introduced to the reader by name, with their unique personalities, interests, and gifts described. However, we live in a world where autism is still very much stigmatised and where disclosure comes with significant risks to career progression and social inclusion. Thus, many of the participants have asked to remain anonymous, and their combined stories are shared in a way that gives the reader a sense of their diversity while maintaining their anonymity.

This, then, was the final culmination of a succession of dreams that had emerged progressively in 11 steps or stages that had begun in antiquity. In logical order, the several steps were from: (1) the birth of ancient Greek and other myths of flight, to (2) proposals for machines that would make flight possible by mimicking the flapping wings of birds, to (3) actual attempts at human flight, to (4) successful human flight through the air by means of balloons, to (5) powered, controlled, sustained human flight through the atmosphere by winged vehicles, to (6) fictional accounts of flying to the Moon, to (7) the invention of rockets leading to an understanding of the principles of space flight, to (8) the Apollo Project Moon landings, to (9) fictional accounts of traveling to Mars, to (10) actual landings on Mars by rockets and robotic rovers, to (11) the idea of leaving Earth and colonizing the universe.

Self-organized criticality (SOC) is a theoretical concept that describes the statistics of nonlinear processes. It is a fundamental principle common to many nonlinear dissipative systems in the universe. Due to its ubiquity, SOC is a law of nature, for which we derive a theoretical framework and specific macroscopic physical models. Introduced by Bak, Tang, and Wiesenfeld in 1987, the SOC concept has been applied to laboratory experiments of sandpiles, to human activities such as population growth, language, economy, traffic jams, or wars, to biophysics, geophysics, magnetospheric physics, solar physics, stellar physics, and to galactic physics and cosmology. From an observational point of view, the hallmark of SOC behavior is the power law shape of occurrence frequency distributions of spatial, temporal, and energy scales, implying scale-free nonlinear processes. Power laws are neither a necessary nor a sufficient condition for SOC behavior, because intermittent turbulence produces power law-like size distributions also. A novel trend that is ongoing in current SOC research is a paradigm shift from “microscopic” scales toward “macroscopic” modeling based on physical scaling laws.

The author describes his parents’ upbringing and move to New York around the time of the Great Depression. The young Weinberg is encouraged to read widely and later takes inspiration from Norse myths from the Poetic Edda.

An overview of General Relativity is provided to a basic level. Its different nature with respect to the Newtonian Universal Gravitation is outlined. A cursory resume of the post-Newtonian approximation and its importance in testing Einstein’s theory is offered. A brief overview on the modified models of gravity that appeared in the last decades is outlined. A plan of the book is provided.

The first part of this chapter introduces and defines key concepts that are commonly encountered in this subject: astrobiology, habitability, and life; in doing so, it also clarifies the ambiguities inherent in these terms. The second part briefly chronicles the lengthy and rich history of speculations about the plurality of worlds and extraterrestrial life in myriad societies across different epochs. It concludes with a summary of developments in astrobiology in the early- and mid-twentieth century, and describes how the future of this field looks optimistic.

The chapter provides a brief overview of the first three major eras, out of four, in the development of cosmology. The first era started with “prehistory” of cosmology in antiquity, continued with the major contributions of Newton and the nineteenth-century debates on thermodynamics conditions at the cosmic scale, and ended with a “quantum leap” in relevant observational capacities at the beginning of the twentieth century. The second era saw cosmology develop as a mathematical game of sorts, rather than a physical theory predicated on Einstein’s General Theory of Relativity. It was marked by Einstein’s static model of the universe and a static model by De Sitter. A cosmological revolution began in the third era (from 1929 to 1948), with the development of expanding models of the universe that captured its physical dynamics.

How do you write a book about things, life and language on planets outside our own Solar System, when you do not even know if they exist or not? The only sensible answer is by looking at how life developed on Earth1 and then considering how this could manifest itself on exoplanets, those beyond the planets which orbit our star, the Sun. This is because when considering possible Earth-like planets (see Section 8.8 for 10 criteria) we have, at our present state of knowledge, a set consisting of only one member, our Earth; this is the ‘set of one’ issue (Figure 1.1).

The first chapter presents the discovery of the galactic interstellar medium of gas and dust. The discovery of interstellar carbon monoxide is described and the implication thereof for the study of the formation of stars is explained. The race to maintain primacy in the burgeoning new field of interstellar molecular spectroscopy leads to a proposal for the United States to build a 25 m diameter telescope.

After a discussion of best programming practices and a brief summary of basic features of the Python programming language, chapter 1 discusses several modern idioms. These include the use of list comprehensions, dictionaries, the for-else idiom, as well as other ways to iterate Pythonically. Throughout, the focus is on programming in a way which feels natural, i.e., working with the language (as opposed to working against the language). The chapter also includes basic information on how to make figures using Matplotlib, as well as advice on how to effectively use the NumPy library, with an emphasis on slicing, vectorization, and broadcasting. The chapter is rounded out by a physics project, which studies the visualization of electric fields, and a problem set.

This chapter recounts the history of theological and philosophical discussions about whether there are, or could be, other habitable worlds beyond Earth.

Newton's Universal Law of Gravitation is compared and contrasted to Coulomb’s Law and the differences highlighted. Tides are discussed, and the Equivalence Principle and how it leads to the notion of curved space-times is explained.

Karl Jansky’s illness led to his being assigned to a remote New Jersey Bell Telephone Labs site to investigate interference to transatlantic telephone circuits. In a series of personal letters written to his father, Jansky documented his two-year investigation leading to the discovery of radio emission from the center of the Milky Way. Pressure to work on defense-related projects and the growing tensions between Jansky and his supervisor Harold Friis led to a long-standing controversy about why Jansky did not continue his study of “star noise.” Although the astronomical community showed little interest in Jansky’s discovery, Grote Reber, a young engineer and avid radio amateur, built the world’s first radio telescope using his own private funds. After negative results because he was misled by the then prevailing theories of cosmic radio emission, Reber finally confirmed Jansky’s discovery and demonstrated that, unlike all previously known cosmic radiation, galactic radio emission was nonthermal. The work of Jansky and Reber set the stage for the later series of remarkable radio astronomy discoveries made possible by the wartime developments in radio and radar technology.

Space tourism began in 2001 when an American investment manager paid the Russian space agency US$20 million to travel to the International Space Station on a Soyuz rocket. In 2021, three US-based companies began launching tourists on their own rockets: Virgin Galactic, Blue Origin and SpaceX. The emergence of Space tourism raises difficult issues. One such issue is the environmental effects of launches on the atmosphere and the corresponding implications for climate change. Space tourism also raises difficult questions of international law, including, where does space begin? Who gets to call themselves an ‘astronaut’? Do states have a duty to rescue tourists stranded in space?

The opening chapter introduces the most significant areas of contemporary research in the molecular astronomy of star formation: prestellar cores, hot cores, hot corinos, accretion, protoplanetary disks, photodissociation regions (PDRs), HII regions, stellar jets, disk winds, outflows, and masers. These sit within the wider considerations of dense molecular clouds on many scales, from the giant molecular clouds (GMCs) to fragments, filaments, and clumps. Our understanding of these molecular cloud environments depends on our understanding of molecular excitation, energy balance, gas and grain surface reaction kinetics, cosmic ray ionization, and photochemistries. Chemical modelling involving both gas-phase and grain-surface reactions is described, as are the observational and analytical essentials of antenna temperature, optical depth, velocity distribution, column density, beam dilution, relative abundance, rotation diagrams, and radiative transfer modelling.

Gravity has an irresistible grip on our curiosity and is able to drive our imagination to completely different theoretical spaces. This very fact alone sets gravity aside from all other types of physical interactions we know. Indeed, gravity is the only physical interaction of which we have a conscious experience and this awareness is with us every second of our life. In this book we set out to try to address the question: '…what is gravity and how does gravity actually work?'. This book is meant as a guide in a journey that will take us from our basic understanding of gravity, the one that is deeply coded in our brains even at an instinctive level, to the more physically detailed and yet incorrect description provided by Newton’s theory of gravity. The journey will then lead us to the mathematically beautiful and physically profound description that Einstein has proposed with his 'general theory of relativity', and that is elegantly embodied in his field equations.