Fact and Fancy
Isaac Asimov's "Fact and Fancy" explores various scientific topics through speculations and factual information, encompassing astronomy, the nature of life's bottlenecks, and the processes of scientific discovery and skepticism.
"Fact and Fancy" by Isaac Asimov, published in 1963, is a collection of seventeen speculative essays on science and its possibilities, intended to entertain and enlarge the reader's horizons. Asimov, a prolific author of science and science-fiction books, was also an Associate Professor of Biochemistry at Boston University, though he later devoted his time fully to writing. This book aims to present "startling ideas" and "sound scientific information" in an engaging manner.
Introduction
In the introduction, Asimov reflects on the contrasting nature of fiction and science writing. He notes that while a novelist can freely invent and embellish, a science writer is bound by facts and faces scrutiny for any deviation. However, Asimov believes there is a "middle ground" between rigid fact and complete lie, which he terms "fancy". To him, the truths of science, not yet fully revealed, hold a greater fascination than any fiction. He resolves his "dilemma" by blending facts with the "gauzy wings of fancy" in his essays, most of which originally appeared in The Magazine of Fantasy and Science Fiction. He hopes that the reading experience will be as enjoyable as the writing process.
Life's Bottleneck
In "Life's Bottleneck," Asimov explores the limitations on the growth of life due to the finite supply of essential elements and energy. He uses the analogy of copepods in the ocean to illustrate how a single "everything else" component can be entirely incorporated into living organisms, leaving behind pure water. He identifies phosphorus as the primary bottleneck for life in the euphotic zone of the ocean, where sunlight is abundant. Below this zone, energy becomes the bottleneck. On land, plant life, upon which animal life depends, derives most elements from soil minerals. Asimov notes the serious loss of phosphorus from land to sea via rivers, with only a small percentage returned through bird droppings (guano). He also considers the carbon dioxide supply in the atmosphere, suggesting it might be used up by plant life in a few decades if not for the recycling process through the decay of dead plant matter.
Catching Up with Newton
"Catching Up with Newton" delves into the concept of gravity, starting with Galileo's observation that water pumps could not lift water beyond a certain height. This leads to the understanding of atmospheric pressure. Torricelli's experiments with mercury further demonstrated the weight of the atmosphere. Von Guericke's Magdeburg hemispheres dramatically illustrated the power of air pressure. The essay then discusses how scientists like Robert Boyle and Blaise Pascal explored the properties of the atmosphere at different altitudes. Asimov then transitions to Newton's law of universal gravitation, explaining the relationship between the force of attraction, mass, and distance (f= Gm₁m₂/d²). He simplifies this equation by using relative units to show that the force of attraction is inversely proportional to the square of the distance (f = 1/d²). The concept of escape velocity is introduced, noting that it decreases with increasing distance from Earth. Finally, the different types of orbits (elliptical, parabolic, hyperbolic) are explained in relation to a missile's velocity with respect to Earth and the Sun.
Catskills in the Sky
"Catskills in the Sky" playfully imagines potential tourist destinations within our solar system. Asimov describes the spectacular view of a solar eclipse from the Moon. He envisions visiting Jupiter and its colorful, stormy atmosphere and giant satellites. Saturn's rings are presented as a "uniquely beautiful sight," although the viewing angle changes over time. The most "frightening and ferocious" tourist view would be a close approach to the Sun, specifically from the planetoid Icarus during its perihelion. Asimov suggests that a scientific laboratory could be established on Icarus to observe the Sun's magnificence.
Beyond Pluto
"Beyond Pluto" explores the possibility of a tenth planet in our solar system, starting with Titius's (and later Bode's) law, which proposed a mathematical relationship for planetary distances. The discovery of Ceres, a planetoid in the predicted gap between Mars and Jupiter, initially seemed to support this law. However, Neptune and Pluto's distances did not perfectly fit the pattern. Asimov recalculates the Titius series to predict the location of a potential tenth planet, suggesting a mean distance of 7.2 billion miles from the Sun. He speculates on how the Sun would appear from such a distance – a bright point of light – and how astronomers on this planet would have an excellent vantage point for measuring stellar parallax. He proposes naming the tenth planet Charon and its first satellite Cerberus, drawing from classical mythology related to Pluto (Hades).
Steppingstones to the Stars
"Steppingstones to the Stars" discusses the possibility of a vast shell of icy planetoids surrounding the Sun far beyond Pluto, also known as the Oort cloud, and their connection to comets. Historically, comets were seen as atmospheric phenomena. Tycho Brahe's observations in 1577 proved they were celestial bodies. Edmond Halley correctly predicted the return of the comet now named after him, establishing comets as members of the solar system with predictable orbits. Despite their often enormous appearance, comets have very small masses and low densities. Professor Fred Whipple's "dirty snowball" theory describes comets as being largely composed of ices that evaporate as they approach the Sun, forming the tail. Asimov explains how this distant shell of icy bodies could have formed from the outer regions of the original solar nebula. While individual cometary planetoids would be far apart, a perturbed orbit could send one inwards, potentially serving as a "steppingstone" for future interstellar travel.
The Planet of the Double Sun
"The Planet of the Double Sun" explores a hypothetical scenario where our Sun has a binary companion, similar to Alpha Centauri. Alpha Centauri is revealed as a triple star system, with Alpha Centauri A being very similar to our Sun. Asimov imagines a smaller companion star, "Sun B" (or Prometheus), orbiting our Sun at a distance of 2 billion miles. This "Sun B" would appear as a very bright point of light in our sky, even visible during the day. He speculates on how the Greeks might have interpreted such a phenomenon, possibly weaving it into their mythology, with "Prometheus" stealing light from the Sun. Asimov also considers how the presence of a binary sun might have influenced Greek astronomy and their geocentric view of the universe.
Heaven on Earth
In "Heaven on Earth," Asimov attempts to make the vast scales of the universe comprehensible by imagining everything scaled down to the size of Earth. He uses angular measurements and comparisons to familiar objects like a quarter to illustrate the apparent sizes of celestial bodies. Tables are presented showing the maximum angular diameters of planets and their scaled linear diameters on Earth's surface. Stars, even giants like Betelgeuse, would appear as relatively small discs even with significant magnification. Asimov assumes all stars have the same intrinsic brightness as the Sun to create a scale of comparative areas and diameters on Earth. He concludes that even with countless stars, the sky is relatively uncrowded, and the average distance between stars on this Earth-scale would still be considerable.
Our Lonely Planet
"Our Lonely Planet" discusses the number of stars visible to the naked eye. Asimov recounts the biblical expression of vast numbers as "stars in the heaven" but notes that the actual number visible without aid is far fewer than commonly imagined, around 2500 from a dark location. He explores how the lack of atmosphere on the Moon would allow for the visibility of more stars, roughly double the number seen from Earth. He contrasts the sparsely populated region of our Sun in a spiral arm of the Galaxy with the densely packed centers of galaxies and globular clusters. Asimov also considers how the night sky would appear if all nearby stars were as bright as Sirius, resulting in a sky as bright as the full Moon. He briefly touches upon Population I and Population II stars, noting their different distributions and ages within galaxies.
The Flickering Yardstick
"The Flickering Yardstick" chronicles the historical efforts to determine the size of the universe, focusing on the role of Cepheid variable stars. Early estimates of the Milky Way's size were made by astronomers like Kapteyn. Henrietta Leavitt's discovery of the period-luminosity relationship for Cepheids provided a crucial "flickering yardstick" for measuring cosmic distances. Harlow Shapley used RR Lyrae variables in globular clusters to map the Galaxy, realizing the Sun was not at the center. Cepheids in the Magellanic Clouds helped determine their distances. Edwin Hubble's observation of Cepheids in the Andromeda nebula proved it was a separate galaxy at a great distance, vastly expanding the known universe. Walter Baade's work during wartime blackouts revealed two populations of stars with different characteristics, leading to a recalibration of Cepheid distances and a significant increase in the estimated size of the universe and the age of galaxies.
The Sight of Home
"The Sight of Home" explores the visibility of our Sun from other star systems and other stars from our system, using the concepts of apparent and absolute magnitude and the distance modulus equation (M = m + 5 - 5 log D). Asimov explains how to correct for distance to determine a star's intrinsic brightness (absolute magnitude). He calculates that the Sun would only appear as a first-magnitude star from a planet in the Alpha Centauri system. Less luminous stars like "Joe" would be barely visible even at relatively close distances. Conversely, more luminous stars like Sirius, Capella, and Rigel would be visible over much greater distances. The extraordinarily luminous star S Doradus in the Large Magellanic Cloud is also discussed. Asimov then examines novae and supernovae, their immense temporary increases in brightness allowing them to be seen across vast cosmic distances. He cites historical supernovae like the Crab Nebula (1054), Tycho's nova (1572), and Kepler's star (1604). He also considers the impact of a nearby star like Alpha Centauri becoming a nova or supernova.
Here It Comes; There It Goes
"Here It Comes; There It Goes" discusses Reginald O. Kapp's "Unified Cosmology," which proposes the continuous extinction of matter. Kapp suggests three possibilities for the origin of the universe: no origin, creation from nothing, or existence for eternity. He favors continuous creation but addresses issues related to the second law of thermodynamics and entropy. Kapp proposes that matter continuously disappears, with a half-life of roughly 800 million years. Asimov presents a thought experiment (which he absolves Kapp of responsibility for) relating the size of animals to the strength of their supporting structures to potentially test this theory.
Those Crazy Ideas
"Those Crazy Ideas" delves into the nature of scientific creativity, sparked by a request from a consulting firm for "crazy ideas". Asimov uses the parallel discovery of natural selection by Charles Darwin and Alfred Russel Wallace as a case study. He identifies five criteria for scientific creativity: 1) broad education (possession of many diverse "bits" of information), 2) intelligence (ability to understand and manipulate these "bits"), 3) intuition (ability to form new and non-obvious combinations of "bits"), 4) courage (willingness to champion these new ideas), and 5) luck (encountering the necessary "bits" at the right time, as Darwin and Wallace did with Malthus's work). He also discusses the potential and limitations of "brain-busting" group sessions for fostering creativity.
My Built-in Doubter
"My Built-in Doubter" emphasizes the crucial role of skepticism and doubt in scientific thinking. Asimov recounts being asked about flying saucers, highlighting the common misconception that science-fiction writers necessarily believe in pseudoscience. He argues that a scientist must constantly question observations, data, and theories, including their own. However, this doubt must be intelligent and proportional to the authoritativeness of the source and the nature of the claim. Asimov uses examples like the ionic theory of solutions and Kepler's mystical beliefs to illustrate how doubt helps filter out incorrect ideas and guide scientific progress. He also notes how well a new observation fits into the existing structure of science influences the intensity of doubt it should face.
Battle of the Eggheads
"Battle of the Eggheads" addresses the perceived conflict between the sciences and the humanities, particularly in the context of the Soviet Union's Sputnik launch and the subsequent focus on science education in the United States. Asimov criticizes anti-intellectualism and the notion that the humanities are inherently superior to the sciences in terms of culture. He argues that in the modern world, science plays a vital role in all aspects of human life, and therefore, a truly educated person, a true humanist, must have some understanding and appreciation of science. He refutes the fear that an emphasis on science will produce uncultured "robots," asserting that many scientists have broad interests in the humanities. Asimov advocates for an end to intellectual dilettantism and for recognizing science as an integral part of modern human concerns. He suggests that the "humanities" should evolve to include scientific understanding.
In conclusion, "Fact and Fancy" showcases Isaac Asimov's talent for taking complex scientific concepts and making them accessible and engaging for a general audience. Through a series of thought-provoking speculations and explanations grounded in current scientific knowledge of the time, Asimov explores a wide range of topics, from the fundamental limits of life and the nature of gravity to the vastness of the universe and the process of scientific discovery. He consistently blends factual information with imaginative "fancy" to ignite curiosity and foster a deeper appreciation for the wonders of science. The book underscores the importance of both knowledge and imagination in scientific exploration, as well as the necessity of critical thinking and a broad understanding of the world in an age increasingly shaped by science and technology.
