Skywatchers of the world, a history of astronomy

A book in 22 chapters, from notched bones and stone circles to the telescopes of today. Every people on Earth watched the sky, and most of them wrote down, built or sang what they saw. This book gives each of them its due: Babylon and Egypt, China, India, Korea and Japan, Greece, Baghdad and Samarkand, Timbuktu, the Maya and the Inca, the navigators of the Pacific and the oldest astronomers of all, in Australia.

How to read it

• In order, or by region. The chapters run roughly by time, but each region's chapter stands on its own.
• Every level. Each chapter starts with the story, for any reader. Later sections show the evidence (what was found, how it was dated, the numbers behind it), and the last ones give the arguments that experts still have.
• Where the evidence is thin, the chapter says so. Some famous claims are well supported, some are guesses, and some have been shown to be wrong. Each one is marked.
• The science is in the other books. When a chapter needs an idea such as a lunar month or a solstice, it explains it briefly and links to the physics lessons for the full story.

Timeline

The turning points, in date order, with the part of the world each one belongs to and a link to the page that tells the story.

Year	Region	Event	Why it mattered
c. 43,000–42,000 years ago	Africa	A baboon bone at Border Cave, South Africa, is notched in four sets	Notation this old is rare; it is often called a Moon count, which the notches do not show
c. 25,000–16,000 years ago	Africa	The Ishango bone, Congo, is notched in three columns	Arithmetic, a calendar or counting in twelves: still unproven
c. 8000 BC	Europe	Hunter-gatherers dig twelve pits at Warren Field, Scotland, facing the midwinter sunrise	Possibly the oldest calendar, a Moon count reset each midwinter
c. 4500–4000 BC	Africa	Herders at Nabta Playa, Egypt, set up a stone circle with a solstice sightline	The Sun watched beside a seasonal lake in the Sahara; star claims unproven
c. 3200 BC	Europe	Newgrange, Ireland, is built with a roof-box for the midwinter sunrise	A feature with no use but to let in the solstice Sun
c. 3000–2500 BC	Europe	Stonehenge is laid out on the solstice line	The best-known solar alignment, rebuilt over 1,500 years
c. 2100 BC	China	A platform with twelve slots for the sunrise is built at Taosi	A horizon calendar marking both solstices
buried c. 1600 BC (disputed)	Europe	The Nebra sky disc is buried on the Mittelberg, Germany	The oldest known picture of the sky: Moon, Pleiades and the Sun's 82° swing
250–200 BC	Americas	Thirteen towers are built at Chankillo, Peru	A complete solar calendar on the horizon, accurate to a day or two
date not known; living tradition	Australia	The Wathaurung build Wurdi Youang; the Emu in the Sky is read in the Milky Way's dark clouds	Solstice and equinox sunsets marked twice over; knowledge still held today

Contents

Part	Chapter
I. The first skywatchers	1. Before writing
	2. Mesopotamia
	3. Egypt
II. Asia	4. China
	5. India
	6. Korea and Japan
III. The Mediterranean and the Islamic world	7. Greece and Alexandria
	8. The Islamic world and Persia
	9. Byzantium and medieval Europe
IV. Africa, the Americas and the Pacific	10. Africa
	11. The Americas
	12. Oceania and Australia
V. A new picture of the heavens	13. Copernicus and his debt to Maragha
	14. Tycho and Kepler
	15. Galileo, and the telescope goes round the world
	16. Newton, Halley and Rømer
	17. Herschel, and the canals of Mars
VI. The modern sky	18. Light split into colours
	19. Galaxies and the expanding universe
	20. Radio astronomy
	21. The space age at Mars
	22. Astronomy today