The Planets

Dava Sobel’s talent for portraying scientific advances within their cultural contexts made her earlier books international best sellers. In Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time (1995), she dramatized not only John Harrison’s invention of the chronometer and but also his agonizing struggle for recognition. In Galileo’s Daughter: A Historical Memoir of Science, Faith, and Love (1999), she illuminated Galileo Galilei’s unfailing devotion to his religion and family as well as to science. In her recent work The Planets, she once again explores the human dimension of her subject, combining her personal attraction to the study of planets with a survey of their factual and not infrequently fabulous cultural dimensions.

Modern astronomers have employed technology to refine scientific descriptions of the planets, the sun, and the solar system as a whole, providing new data that reverberate with cosmic energy. In The Planets, Sobel reveals how traditional notions of the heavens relate to these new discoveries. Her chapter titles suggest her method, as she discusses the Sun in “Genesis,” Mars in “Sci-Fi,” Uranus and Neptune in “Night Air,” and so on.

Sobel opens by recalling the origins of her fascination with the planets in the chapter “Model Worlds.” During elementary school in the 1950’s, she became enamored of the planets, seeing them as reliable yet exotic beings where unlimited strangeness was circumscribed by the unusual qualities of the number nine. Nine planets could not be reckoned in pairs or dozens or manipulated with zeroes or fives but could be counted on the fingers. Her initial attraction to the planets was intensified by activities that included constructing a shoebox diorama for a science fair, appearing in a class play as “Lonely Star,” and visiting the Hayden Planetarium. Viewing the enormous Willamette meteorite awakened her to the possible threat to Earth from the skies above.

Sobel’s memoir lays the groundwork for appreciating the enormous progress of more recent space exploration. Within the past few decades, unmanned space probes have revealed previously unknown details about the planets, including the existence of “new” moons and multiple rings around Jupiter, Saturn, Uranus, and Neptune. “Model Worlds” concludes with a reference to exoplanetsplanets that astronomers have calculated to exist in other solar systems. In effect, current knowledge of Earth’s planetary system has become the basis for detecting many other systems.

In “Genesis,” Sobel relates the biblical story of creation to the big bang theory of creation. Scientists attribute the beginning of the universe to the emergence of a hot light bursting from a dark and timeless void. As the light rapidly cooled, it created an entire universe of matter and energy. Sobel describes the stages of development of the solar system, in which the Sun draws itself into being, amassing 99.9 percent of the available matter swirling in a remote corner of a remote galaxy and leaving a mere 1 percent for all the planets. Her portrait of the Sun continues with a discussion of sunlight, solar winds, and eclipses.

The structure of Sobel’s book extends from the Sun to the outer planets, with individual chapters devoted to the “terrestrial planets” of Mercury, Venus, Earth, and Mars. In “Mythology,” Sobel notes that Mercury (the Roman name for the Greek messenger-god Hermes) is probably so-named because of the planet’s swift and brief appearances at or near the horizon. Ancient astronomer Ptolemy plotted the orbit of Mercury as traversing the earth just beyond the orbiting moon, but Sobel discusses its true profile in regard to orbit, rotation, and heatthe fevered light of the Sun always bearing down directly on Mercury’s equator.

Mercury’s proximity to the Sun has historically caused astronomers difficulty. Even Copernicus, developing his theory that the planets revolved around the sun,...

(The entire section is 1659 words.)