Quest for planet of love

PUBLISHED : Sunday, 20 May, 2012, 12:00am
UPDATED : Sunday, 20 May, 2012, 12:00am


Chasing Venus: The Race to Measure the Heavens
by Andrea Wulf

Venus, the planet of love, has beguiled scientists since modern astronomy began. In 1716, British stargazer Edmond Halley (of comet fame) urged astronomers across Europe to join him in a bid to gauge the size of our solar system by tracking the planet's two scheduled transits across the sun. Halley would die before the transits, in 1761 and 1769, but he set prows in motion.

As historian Andrea Wulf recounts in her topical historical travelogue, Chasing Venus: The Race to Measure the Heavens, a starry cast of characters joined the mission, personally crisscrossing the ocean or dictating proceedings.

Participants included Catherine the Great, who dispatched Russian explorers. There were Charles Mason and Jeremiah Dixon, who later carved the Mason-Dixon Line across America. Other big names ranged from British explorer Captain James Cook to the captivatingly hapless French stargazer Guillaume Le Gentil.

Le Gentil acted first, leaving France in March 1760. Dodging the British, he tacked across the Indian Ocean to view the first transit from the French trading port Pondicherry on India's southeastern coast. Le Gentil, Wulf wryly writes, had a 'seemingly unwavering talent for attracting problems'.

One was fellow French observer Alexander Guy Pingre, who took a similar path. Wulf describes the gout-ridden Pingre with aplomb: 'His heavy frame and chubby face hinted at his jovial nature and sensuous joy in the good things of life,' she writes.

'He was a polymath and ordained priest who had studied and taught theology as well as writing about linguistics, music, poetry and, of course, astronomy. His friendly and lively eyes, though, belied a wilful character. In the past he had incensed his church so much with his unorthodox opinions that they [sic] had placed him in an obscure elementary school in the provinces.'

There, Pingre was bored, but he kept busy, churning out scientific letters and essays before applying his wayward talents to the Venus project. One of science's first joint global efforts, the project was marred by tricky weather, squabbling and - worst of all - the 1756-1763 war between the French and British.

Le Gentil, meanwhile, was dogged by dysentery, hurricanes and enemy attacks. Just two weeks before the first, 1761 transit, he learned the British had taken Pondicherry. The result: he needed to see the transit from the sea, aboard a bucking boat, making exact observations impossible. Despite 'his talent for sugar-coating the most dreadful situation', Le Gentil despaired then decided to wait for the second transit at Pondicherry. When this transit finally rolled up in 1769, however, he saw only clouds.

Pingre also floundered. At the first transit, based on the Mauritian island of Rodrigues, he mostly saw rain and cloud. Adding to his woes, the British sacked the island and took the only two available ships, leaving him stranded. Pingre fumed but would eventually succeed in viewing the second transit from Haiti. Cook also saw the second transit, from Tahiti.

The big winner was French astronomer Jean-Baptiste Chappe d'Auteroche. A baron's son, he had been passionate about mathematics since childhood, and saw both transits. He produced successful recordings but died of typhus just days after his 1769 glimpse.

Chasing Venus underscores the fragility of the human condition in the crazy Enlightenment age that Wulf evokes with gusto. Take the 1768 episode where, as Hungarian astronomer Maximilian Hell and assistant Janos Sajnovics languish in Norway, Captain Cook's crew - including botanist Joseph Banks - leave Rio de Janeiro in party mood.

'While Hell and Sajnovics treated themselves to a chaste hot chocolate on 25 December in Vardo, Cook's men enjoyed a more bawdy feast where 'all hands g[o]t abominably drunk',' Banks reported. But the hot weather soon changed, and temperatures dropped rapidly. At Cape Horn, which was feared for its volatile winds and vicious currents, the Endeavour was tossed by icy gales. Waves buffeted the vessel so hard that the furniture overturned and Banks' entire library tumbled through the cabin. During the nights they were bashed in their hammocks against the ceiling and walls. On an ill-fated plant-collecting expedition to Tierra del Fuego at the southern tip of South America, disaster struck when some of the men were caught on shore by a sudden blizzard and perished, Wulf writes.

Wulf, who released her horticultural take on the American revolution, The Founding Gardeners, last year and another leafy historical tome, The Brother Gardeners, in 2010, is a class act. 'Throughout The Brother Gardeners, Wulf's flair for storytelling is combined with scholarship, brio and a charmingly airy style,' The New York Times Book Review says. The same applies to Chasing Venus.

One gripe: at heart, Chasing Venus feels rather safe - yet another popular exposition of a scientific theme a la Longitude by Dava Sobel.

Some might ask whether the world really needs another historical travelogue ripe for a Hay Festival reading.

That said, Chasing Venus has a seductively rollicking, mischievous streak and topical traction: on June 5 or 6, depending on time zone, millions of people around the world will see Venus inch across the sun in another occurrence of the celestial marvel that will not repeat until 2117. Because Venus is just a fraction of the sun's width, it will appear as a black speck. Even if the weather is a washout, you can track the speck's six-plus-hour trek from the comfort of your apartment via US space agency Nasa's live remote webcast from atop Mauna Kea in Hawaii.

What would some of the stargazers paraded in Chasing Venus have given for such wizardry? Procedural cock-ups pepper the pages of Chasing Venus, while the planet made the hunt tougher by playing hard to get.

At Vardo at 3pm on June 3, 1769, clouds covered the sky. At 6pm, the sun peeped through the curtain. At 9pm, with the transit just minutes away, those geeky stay-at-homes Hell and Sajnovics pointed their telescopes. On cue, the clouds opened. Heaven obliged, displaying the divine dot.

As the two astronomers thanked 'the special grace of god', the local garrison commander raised the flag. Locals scurried to the observatory for their glimpse of the magical celestial event. But by the time they gathered around the telescope, to their dismay they found that the sun had gone again. Some would-be observers adapted well to frustration. When a thunderstorm obscured the 1769 sky in Leiden, in the Netherlands, one individual resolved to see an ''earthly Venus'' in the opera house instead, knowing the celestial transit would not unfold for another 105 years.

Despite all the blips, the data gleaned from all corners of the globe was finally triangulated, yielding the desired solar system map.

Side benefits included increased global scientific co-operation. 'The transit projects revealed the importance of international communication and collaboration,' Wulf writes.

'Never before had scientists and thinkers banded together on such a global scale - not even war, national interests or adverse conditions could stop them. The intensity of their commitment was unparalleled and the international ties it fostered remained in place long after the transits.'

Thanks to the Venus collaboration, even discoveries that countries could have used against each other were now shared. The shining planet apparently deserved its connection with the Roman goddess of love.