“Fueled by fossils,” by John Steele Gordon (original) (raw)
Humans like to think by analogy, and this method often works well for advancing knowledge. For instance, when Galileo first turned his new telescope towards the heavens in 1609–10, he quickly noted four dots of light that were aligned with Jupiter’s equator. Over the next few nights, while the dots stayed aligned, he saw that they moved significantly from one side of the planet to the other and back, occasionally disappearing behind it. By analogy to the Copernican model of the solar system, he quickly deduced that they were moons in orbit around the giant planet, known ever since as the Galilean moons. As the first celestial objects seen to be orbiting a body other than the earth, they proved to be the earliest observational nail in the coffin for Ptolemy’s geocentric model of the universe.
But when Galileo turned his telescope to Saturn, analogy failed him and he was mystified by what he saw. His primitive instrument could not focus the different wavelengths of visible light at the same plane (which is to say, at his retina), so the image he saw was a bit fuzzy. He thought Saturn might be three planets and he also described what he saw as “Saturn’s ears.” In 1612, when the earth passed through the plane of Saturn’s rings and they became briefly invisible, he wondered, “Has Saturn swallowed his children?”—a reference to the ancient Greek myth. It was only in 1659 that more powerful telescopes were able to show
John Steele Gordon is the author of An Empire of Wealth: The Epic History of American Economic Power (Harper Perennial).
This article originally appeared in The New Criterion, Volume 43 Number 5, on page 65
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