Archives of the Universe: A Treasury of Astronomy's Historic Works of Discovery - Hardcover

Bartusiak, Marcia

Hardcover

ISBN 10: 037542170X ISBN 13: 9780375421709

Publisher: Pantheon, 2004

Synopsis

An unparalleled history of astronomy told through 100 primary documents—from the Maya’s first recorded efforts to predict the cycles of Venus to the 1998 paper that posited an accelerating universe.

Award-winning science writer Marcia Bartusiak is a wonderfully compelling guide in this sweeping overview. Her authoritative, accessible commentaries on each document provide historical context and underscore the more intriguing and revolutionary aspects of the discoveries.

Here are records of the earliest naked-eye celestial observations and cosmic mappings; the discovery of planets; the first attempts to measure the speed of light and the distance of stars; the classification of stars; the introduction of radio and x-ray astronomy; the discovery of black holes, quasars, dark matter, the Big Bang, and much more. Here is the work of Copernicus, Galileo, Kepler, Newton, Halley, Hubble, and Einstein, as well as that of dozens of lesser-known scientists who have significantly contributed to our picture of the universe.

An enthralling, comprehensive history that spans more than two millennia—this is essential reading for professional astronomers, science history buffs, and backyard stargazers alike.

About this title

About the Author:

Marcia Bartusiak is the author of Thursday’s Universe, Through a Universe Darkly, and Einstein’s Unfinished
Symphony. Her work has appeared in many magazines, including Astronomy, Discover, Science, and Smithsonian. A two-time winner of the American Institute of Physics Science Writing Award, she teaches in the graduate program in science writing at the Massachusetts Institute of Technology and lives in Sudbury, Massachusetts, with her husband.

Excerpt. © Reprinted by permission. All rights reserved.:

The Ancient Sky

The fortuitous alliance of two agents led to the birth of astronomy: curiosity and necessity. From savannas, mountaintops, and forest clearings, the first celestial observers looked up at the nighttime sky and beheld a vast, pitch-black bowl covered with sparkling pinpoints of light. While likely awed at first by this jewel-like canopy, imagining it as a vaulted roof through which the fires of the gods flickered, prehistoric peoples eventually learned there were practical benefits to studying the sky’s incessant motions and cycles.

Tracing out patterns of stars—constellations—became a useful procedure for establishing a coordinate system across the heavens, and the leisurely parade of these stellar figures over the seasons served as valuable markers for navigation, agriculture, and timekeeping. As the Greek poet Hesiod advised in the eighth century b.c., “When the Pleiades, daughters of Atlas, are rising, begin the harvest, the plowing when they set.” Here the farmer was instructed to reap winter wheat in the spring, when the Pleiades rise with the Sun, and to plant seeds in the fall, when the notable constellation sets in the west before sunrise. In ancient Egypt observers noticed that the brilliant star Sirius rose in the east right before dawn, at the very time that the Nile river experienced its annual flooding.

In the high northern latitudes it was the Sun’s recurrent passage that held particular significance. As winter approaches there, the Sun’s path moves steadily southward, just as the days and nights get colder. Primitive megaliths were built to mark the pivotal moment—winter solstice—when the Sun would (to much thanksgiving) turn back and once again rise higher in the sky.

Relics from the first days of civilization showcase the ancients’ intense intellectual curiosity about the nighttime sky. Inscriptions on Chinese oracle bones recorded the appearance of bright comets and “guest stars”; Mayan hieroglyphic books documented the movements of Venus with remarkable precision; clay tablets in Babylonia, dating back nearly four thousand years, chronicled the cyclic movements of the Moon and the “wanderers”—the planets—among the fixed stars. With Alexander the Great conquering Persia in 331 B.C., Babylonia’s tradition of keen skywatching merged with Greece’s focus on geometric models of the universe’s workings.

It was the ancient Greeks who were most influential in moving contemplation of the cosmos from pure mythology to a more reasoned cosmology. They began to wonder about the essential nature of heavenly bodies: how they moved, what they were made of. The first challenge was explaining why that small, elite group of wanderers—the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn—moved at differing speeds and in some cases even stopped and moved backwards in the sky. The Pythagoreans, so enamored of numbers and harmonic relationships, influenced Greek astronomers to solve this problem by thinking of the heavens as a geometric system. With beauty and harmony requiring uniform motion, imaginative models were devised to have the planets move via a set of nested spheres. It was the first attempt at a grand unified theory: explaining celestial motion with a single, all-encompassing mechanism. At the same time, these early astronomers came to understand the source of the Moon’s light, the cause of eclipses, and the true shape of the Earth. They also used their knowledge of geometry to tackle such other questions as the size of our planet and the distances to the Sun and Moon.

There were some prescient speculations on the nature of the solar system in this ancient era. In the fourth century b.c. Heraclides of Pontus suggested that night and day were due to the rotation of the Earth. Aristarchus of Samos later put the Sun at the center of his model of the universe. But these ideas never flourished, as they were overshadowed by the authoritative cosmology espoused by the noted philosopher Aristotle. At the center of his cosmos was the Earth, composed of one of the four basic elements. Surrounding this were water and air. The last element, fire, extended outward to the Moon. In this realm, life was mortal and imperfect. The heavenly bodies, on the other hand, inhabited a domain that was flawless and eternal—the celestial spheres in perpetual circular motion. This model held sway for nearly twenty centuries, and astronomy progressed only when observers such as Hipparchus and Ptolemy dared to tinker with its precepts. Hipparchus discovered the precession of the equinoxes, and Ptolemy cleverly amended Aristotle’s standard model to make it agree better with observation. From these early creative attempts to understand the star-studded sky, a science was born.

1 / Mayan Venus Tables

Some 3,500 years ago the Maya came to occupy a large territory in Central America that now covers southern Mexico, Guatemala, and northern Belize. By A.D. 200 (or even earlier) these native Mesoamericans had advanced from a simple Stone Age existence cultivating maize and squash to a sophisticated civilization whose cities contained impressive stone temples, palaces, and pyramids.

Along with hieroglyphic writing, the Maya developed refined astronomical methods that were representative of astronomical techniques carried out by early societies in other parts of the world—for example, in ancient Egypt and Babylonia. Like the observations made by those other ancient cultures, Mayan stargazing focused on cycles. They viewed the cosmos as a repetitive machine whose operation could offer their society advance knowledge of its fate if the celestial movements could be accurately tracked. Their meticulous observations of the nighttime sky were closely linked with their ritualistic needs.

Of particular importance to the Maya was the planet Venus, whose appearance in the sky follows a distinct pattern. When Venus passes between the Earth and the Sun (a configuration known as inferior conjunction), it cannot be seen for eight days. Eventually Venus is spotted in the morning sky, after it proceeds in its orbit and rises just before the Sun. For 263 days on average it remains visible in the morning, until it passes behind the Sun (superior conjunction) and again disappears. Fifty days later it comes back into view but this time as the evening star, remaining in the night sky for another 263 days until it reaches inferior conjunction once again. The period from one inferior conjunction to the next totals 584 days.

The Maya followed this cycle and recorded their knowledge of its predictability in the Dresden Codex, one of three surviving Mayan hieroglyphic books transported to Europe as spoils of the Spanish conquest. In each book, intricate glyphs are displayed on a single sheet of paper, pounded from the inner bark of a wild ficus tree and folded into separate leaves like a screen. The Dresden Codex, nearly four yards long, has thirty-nine leaves (painted on both sides) and takes its name from the German city in which it now resides. It’s essentially a series of almanacs that chronicle upcoming astronomical events, including lunar and solar eclipses. The glyphs depict a number of gods—some benevolent, others auguring bad tidings. They include the rain gods, the god of maize, a merchant god, a sun god, and a moon goddess, as well as several deities associated with death. Astronomy in this case was being used for divine forecasting, to help farmers predict times of drought, fearsome storms, or an abundant crop.

The Venus tables are found on six pages of the Dresden Codex and tell the reader when Venus will appear and disappear in the morning and evening sky over time. One of the Maya’s greatest achievements in their tracking of Venus was recognizing that the planet’s cycle was not a full 584 days but slightly less (583.92 days). They adjusted their calendar for this difference with astounding accuracy. Concern for such precision is essentially what transformed an astrological endeavor into a science.

The Maya had names for units of time comparable to days, months, decades, and centuries, although on a far different counting system. The uinal (or winal), for example, consisted of 20 days, a sort of month. At times 5 extra days were added. A tun, close to a year, was 360 days. Twenty tuns made up a katun, while 20 katuns was a baktun. A listing of the number of these “centuries,” “decades,” “years,” “months,” and days since some day zero was one way that the Maya generated a calendar. The Mayan Venus tables, though, use another system, where each day is represented by a set of numbers (a dot is one; a bar is five) and names. These dates are listed on the upper left of a page. Notice in Figure 1.1 that every line in this section has four symbol groups. Each specifies an important date in one complete cycle of the Venus period: first the day when Venus will disappear at superior conjunction; next when it reappears as the evening star; then when it disappears at inferior conjunction; and finally when it becomes visible once again as the morning star. Continuing along a selected line across five of the tables (see Figures 1.2 and 1.3) covers a unique period of 2,920 days, over which five Venus cycles equal eight Earth years. At the end, the user of the table moves on to the next line of the five-table chart, where the cycle begins again.

2 / Proof That the Earth Is a Sphere

In 342 B.C. King Philip II of Macedonia brought the learned philosopher Aristotle to his court to tutor his son, who as a man would become Alexander the Great. Soon after Alexander assumed the throne, Aristotle established a school in Athens where he continued his wide-ranging studies in philosophy, logic, politics, physics, and biology.

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About this edition

• Publisher: Pantheon
• Publication date: 2004
• ISBN 10: 037542170X
• ISBN 13: 9780375421709
• Binding: Hardcover
• Edition number: 1
• Number of pages: 720