"Cosmos," Vocabulary from Chapters 1-5

To educate the world about the universe, Carl Sagan developed this book at the same time as the original 1980 television series. Learn this list of words used by the award-winning scientist, philosopher, and author.

Here are links to our lists for the scientific text: Chapters 1-5, Chapters 6-9, Chapters 10-13

Activities for this list:

definitions & notes only words
  1. constituent
    one of the individual parts making up a composite entity
    But presently our journey takes us to what astronomers on Earth like to call the Local Group of galaxies. Several million light-years across, it is composed of some twenty constituent galaxies.
  2. sparse
    not dense
    It is a sparse and obscure and unpretentious cluster.
  3. supernova
    a star that explodes and becomes luminous in the process
    Some stars, the supernovae, are as bright as the entire galaxy that contains them; others, the black holes, are invisible from a few kilometers away.
  4. vaporize
    turn into gas
    Every now and then a passing star gives a tiny gravitational tug, and one of them obligingly careens into the inner solar system. There the Sun heats it, the ice is vaporized, and a lovely cometary tail develops.
  5. extraterrestrial
    originating, located, or occurring outside Earth
    And on the countless other planets that may circle other suns, is there life also? Is extraterrestrial life, if it exists, based on the same organic molecules as life on Earth?
  6. fugue
    a musical form consisting of a repeated theme
    Or is there a kind of cosmic fugue, with themes and counterpoints, dissonances and harmonies, a billion different voices playing the life music of the Galaxy?
  7. carapace
    hard outer covering or case of certain organisms
    How does it come about that the face of a warrior is incised on the carapace of a crab? The answer seems to be that humans made the face. The patterns on the crab’s shell are inherited.
  8. adaptive
    having a capacity for change
    The secrets of evolution are death and time—the deaths of enormous numbers of lifeforms that were imperfectly adapted to the environment; and time for a long succession of small mutations that were by accident adaptive, time for the slow accumulation of patterns of favorable mutations.
  9. primitive
    characteristic of an earlier ancestral type
    In those early days, lightning and ultraviolet light from the Sun were breaking apart the simple hydrogen-rich molecules of the primitive atmosphere, the fragments spontaneously recombining into more and more complex molecules.
  10. molecule
    the simplest structural unit of an element or compound
    This was the earliest ancestor of deoxyribonucleic acid, DNA, the master molecule of life on Earth.
  11. enzyme
    a complex protein produced by cells that acts as a catalyst
    Since mutations are random nucleotide changes, most of them are harmful or lethal, coding into existence nonfunctional enzymes.
  12. regime
    the governing authority of a political unit
    The living cell is a regime as complex and beautiful as the realm of the galaxies and the stars.
  13. viscous
    having a relatively high resistance to flow
    During reproduction, the helices separate, assisted by a special unwinding protein, each synthesizing an identical copy of the other from nucleotide building blocks floating about nearby in the viscous liquid of the cell nucleus.
  14. symbiotic
    of organisms living together, especially to mutual advantage
    This points to a long evolutionary separation of the genetic codes of mitochondria and nuclei, and is consistent with the idea that mitochondria were once free-living organisms incorporated into the cell in a symbiotic relationship billions of years ago.
  15. impetus
    a force that makes something happen
    If we lived on a planet where nothing ever changed, there would be little to do. There would be nothing to figure out. There would be no impetus for science.
  16. lexicon
    a language user's knowledge of words
    We today can recognize the antiquity of astrology in words such as disaster, which is Greek for “bad star,” influenza, Italian for (astral) “influence”; mazel tov, Hebrew— and, ultimately, Babylonian—for “good constellation,” or the Yiddish word shlamazel, applied to someone plagued by relentless ill-fortune, which again traces to the Babylonian astronomical lexicon.
  17. nonsectarian
    not restricted to one school or party
    Almost half of our national flags exhibit astronomical symbols. The phenomenon is transcultural, nonsectarian, worldwide.
  18. arcane
    requiring secret or mysterious knowledge
    All that arcane business about planets ascendant in this or that solar or lunar “house” or the “Age of Aquarius” comes from Ptolemy, who codified the Babylonian astrological tradition.
  19. eschatology
    the branch of theology that is concerned with final things
    He wished to learn the eschatology of the world; he dared to contemplate the Mind of God.
  20. nostrum
    patent medicine whose efficacy is questionable
    Superstition was a widely available nostrum for people powerless against the miseries of famine, pestilence and deadly doctrinal conflict.
  21. polygon
    a closed plane figure bounded by straight sides
    There were known to be five regular or “platonic” solids, whose sides were regular polygons, as known to the ancient Greek mathematicians after the time of Pythagoras.
  22. apogee
    the farthest point in an orbit around the Earth
    He would only, in the course of a meal and, in between other matters, mention, as if in passing, today the figure of the apogee of one planet, tomorrow the nodes of another ...
  23. observation
    facts learned by watching attentively
    After Tycho’s death, Kepler, now the new Imperial Mathematician, managed to extract the observations from Tycho’s recalcitrant family.
  24. ellipse
    a closed plane curve with an oval shape
    Kepler’s first two laws may seem a little remote and abstract: planets move in ellipses, and sweep out equal areas in equal times.
  25. cusp
    point formed by two intersecting arcs
    Kepler stood at a cusp in history; the last scientific astrologer was the first astrophysicist.
  26. intemperate
    (of weather or climate) not mild; subject to extremes
    Because of the length of the lunar day and night Kepler described “the great intemperateness of climate and the most violent alternation of extreme heat and cold on the Moon,” which is entirely correct.
  27. tangential
    acting along a straight line or plane that touches a curve
    The Moon, it seemed to Newton, would fly off in a straight line, tangential to its orbit, unless there were some other force constantly diverting the path into a near circle, pulling it in the direction of the Earth.
  28. antimatter
    mass consisting of antiparticles of normal substances
    This remarkable occurrence is called the Tunguska Event. Some scientists have suggested that it was caused by a piece of hurtling antimatter, annihilated on contact with the ordinary matter of the Earth, disappearing in a flash of gamma rays.
  29. impact
    the striking of one body against another
    But the absence of radioactivity at the impact site gives no support to this explanation.
  30. postulate
    maintain or assert
    Others postulate that a mini black hole passed through the Earth in Siberia and out the other side.
  31. augury
    an event indicating important things to come
    So the idea arose that comets were harbingers of disaster, auguries of divine wrath—that they foretold the deaths of princes, the fall of kingdoms.
  32. predisposition
    an inclination to interpret statements in a particular way
    The featureless clouds of Venus reflected our own predispositions. We are alive, and we resonate with the idea of life elsewhere.
  33. accumulation
    the act of gathering up
    But only careful accumulation and assessment of the evidence can tell us whether a given world is inhabited.
  34. catastrophic
    extremely harmful; bringing physical or financial ruin
    On Venus, on Earth and elsewhere in the solar system, there is evidence for catastrophic destruction, tempered or overwhelmed by slower, more uniform processes
  35. alluvial
    relating to deposits carried by rushing streams
    on the Earth, for example, rainfall, coursing into rivulets, streams and rivers of running water, creating huge alluvial basins; on Mars, the remnants of ancient rivers, perhaps arising from beneath the ground; on Io, a moon of Jupiter, what seem to be broad channels made by flowing liquid sulfur.
  36. vitreous
    relating to or resembling or derived from glass
    But we did not want to land in a place that was too hard either—had we landed in a vitreous lava field, for example, with no powdery surface material, the mechanical arm would have been unable to acquire the samples vital to the projected chemistry and biology experiments.
  37. indigenous
    originating where it is found
    Vishniac believed that the experimental techniques previously used to deduce no indigenous microbes in Antarctica were flawed.
  38. nutrient
    any substance that can be metabolized to give energy
    The nutrients, while suitable for the comfortable environment of a university microbiology laboratory, were not designed for the arid polar wasteland.
  39. attenuate
    become weaker, in strength, value, or magnitude
    On Mars such a place would be even more interesting, because while the visible light necessary for photosynthesis would penetrate to that depth, the germicidal ultraviolet light would be at least partially attenuated.
  40. metabolize
    produce by the organic processes necessary for life
    First, when Martian soil was mixed with a sterile organic soup from Earth, something in the soil chemically broke down the soup—almost as if there were respiring microbes metabolizing a food package from Earth.

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