Ruminations

The Starry Messenger

The New York Times editorial

Published: January 18, 2013

This is a month when anyone with a telescope or good binoculars can gaze up at one of the brightest objects in the night sky and revisit a staggering achievement in astronomy: Galileo’s discovery, over several January days in 1610, of Jupiter’s four largest moons.

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Purchased by J. P. Morgan, Jr. in 1928; MA 1064, The Morgan Library & Museum.

Galileo Galilei (1564–1642), autograph notes on the satellites of Jupiter, January 14–25, 1611.

At first, Galileo thought he was seeing stars. But watching them move in relation to Jupiter, he figured out what they really were — an epiphany that began to upend the given view of the universe.

Here was a celestial body with other celestial bodies circling it. For a biblical cosmology that placed Earth at the center of all that moved, the implications would prove devastating.

The Morgan Library and Museum in Manhattan has a beautifully preserved relic of that scientific triumph: the scrap of an envelope on which Galileo, in 1611, tracked the shifting positions of the Jovian moons. He had published his findings about the moons the year before in “The Starry Messenger,” and he was working, night after night, to better define the periods of the moons’ orbits. In his (literally!) back-of-the-envelope jottings and little pictures, one can sense a great mind puzzling out a perplexing story.

Galileo’s achievement was the end of geocentrism, but it was hardly the end of ignorance and magical thinking. When obstinacy places reason under siege, as it does to this day — when fundamentalism defames biological science in the classroom, or the politics of denial prevent action to deal with a changing climate, it helps to recall our debt to a man who set a different example more than 400 years ago. It took just a wooden tube and some polished lenses, a critical and inquisitive mind, and four points of light that didn’t behave the way they were supposed to.