Traveler's Tales

Travelers’ Tales

One of the main commodities returned on those voyages of centuries ago were traverlers’ tales, stories of alien lands and exotic creatures that evoked our sense of wander and stimulated future exploration.

There had been accounts of mountains that reached the sky; of dragons and sea monsters; of everyday eating utensils made of gold; of a beast with an arm for a nose; of people who thought the doctrinal disputes among Protestants, Catholics, Jews and Muslims to be silly; of black stone that burned; of headless humans with mouths in their chests; of sheep that grew on trees.

Such tales are an ancient human tradition and many of them have had, from the beginning of exploration, a cosmic motif. For example, the fifteenth-century explorations of Indonesia, Sri Lanka, India, Arabia and Africa by the Ming Dynasty Chinese were described by Fee Hain, one of the participants, in a picture book prepared for the Emperor, as the Triumphant Visions of the Starry Raft. Unfortunately, the pictures – although not the text – have been lost.

Anyway, some of these stories were true, some were lies. Other had a kernel of truth, misunderstood or exaggerated by the explorers of their informants. In the hands of Voltaire, say, or Jonathan Swift, these accounts stimulated a new perspective on European society, forcing a reconsideration of that insular world.

Stories of alien lands and exotic creatures evoke our sense of wonder and stimulate future exploration. Image: Change, Celestial Objects © Megan Jorgensen (Elena)

Modern Voyagers also return travelers’ tales, tales of a world shattered like a crystal sphere; a globe where the ground is covered, pole to pole, with what looks like a network of cobwebs; tiny moons shaped like potatoes; a world with an underground ocean; a land that smells of rotten eggs and looks like a pizza pie, with lakes of molten sulfur and volcanic eruptions ejecting smoke directly into space; a planet called Jupiter that dwarfs our own – so large that 1,000 Earths would fit within it.

The Galilean satellites of Jupiter are each almost as big as the planet Mercury. We can measure their sizes and masses and so calculate their density, which tells us something about the composition of their interiors. We find that the inner two, Io and Europa, have a density as high as rock. The other two, Ganymede and Callisto, have a much lower density, halfway between rock and ice. But the mixture of ice and rocks within these outer moons must contain, ad do rocks on Earth, traces of radioactive minerals, which heat their surroundings. We anticipate underground oceans of slush and water in these moons, a hint, before we have ever seen the surfaces of the Galilean satellites close up, that they may be very different one from another. When we do look closely, through the eyes of Voyager, this prediction is confirmed. They do not resemble each other. They are different from any worlds we have ever seen before.