Chasing the Sun: The star gets its due

The Sun is a big subject and Richard Cohen has written a big book about it, an encyclopaedic plum pudding of a compendium. He begins by climbing Mount Fuji to watch a sunrise and ends by watching a sunset from a boat on the Ganges at Varanasi — and in the meantime visits 16 other countries, reads hundreds of books and considers our star from every conceivable perspective, and some that are barely conceivable.

He looks at the science, with its dizzying figures: "The Sun is 32,000 light years from the centre of its galaxy of a hundred billion stars, which it orbits at about 155 miles a second, taking about 200 million years to complete a revolution."

There are at least a hundred billion galaxies, each harbouring a similarly huge number of stars. He looks into the history of the science, from the Sumerians, the Babylonians and the Greeks, who produced 121 astronomers of note. Of these, Heraclitus (c 535BC-475BC) thought the Sun was about the size of a shield and that a new one rises every day while Aristarchus of Samos (310BC-230BC) beat Copernicus by declaring that the Earth must orbit the Sun; and on to Galileo, Newton and Einstein. Many 19th-century scientists thought the Earth was at most 100,000 years old but more than a millennium previously, Hindus reckoned its age at about 4.3 billion years (the estimate now is 4.6 billion).

Cohen covers the evidence for and against man-made global warming and concludes that it is almost impossible to forecast if the poles will melt or if we will be entombed in a new ice age. It is no accident that until the 16th century, "weather" and "whether" were interchangeable spellings.

Many influences

He also explains eclipses, solstices and sunspots, and notes that the French, American and both Russian revolutions coincided with solar eruptions; the next peak of solar storms is due any time now.

He traces the histories of navigation and cartography, of calendars and timekeeping, from clocks of sand, water and incense (by which one smells the hour) to caesium clocks, accurate to one second in 1.4 million years. And he tells us that, instead of a watch, George Washington used a pocket sundial, a present from Lafayette. He surveys solar mythology and though he does not go so far as the 19th-century scholar Friedrich Max Muller, who argued that the Sun is the source of all myths, he still finds it ubiquitous, from ancient Egypt to the modern Vatican, where Pope Benedict XVI has called the Sun "the image of Christ". He looks at the Sun's depiction in art, in music as well as in literature.

There is an excellent chapter on sunbathing, which was banned at Bournemouth until the early Thirties, the permatans of Edward VIII and president Kennedy, and how light-skinned people want darker skins and vice versa. And besides these and other aspects of his subject, Cohen explores many "odd and uncategorisable areas", from the origins of the British tax year, which begins on April 5 because bankers refused to pay their taxes for 11 days when we switched to the Gregorian calendar in 1752, to the fact that astronauts in space grow taller by up to three inches as their vertebrae relax in zero gravity.

In innumerable footnotes, he explores such strictly irrelevant mysteries as the proboscis of Tycho Brahe, the great Danish astronomer who as a student lost most of his nose in a drunken swordfight in the dark and thereafter sported two prosthetic ones: a copper one for everyday use, and a gold and silver one for special occasions.

Beautifully illustrated and competitively priced, Chasing the Sun is not a book to be read at a sitting, but I found it endlessly informative and diverting over a fortnight's holiday in the rain.

- Chasing the Sun: The Epic Story of the Star that Gives Us Life By Richard Cohen, Simon & Schuster, 681 pages, £30