The Transit of Venus by Peter Aughton

A bright planet, but a dark star
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Jeremiah Horrocks's claim to fame is that, in 1639, he was the first person to observe a transit of Venus. These rare events occur in pairs at intervals of more than 100 years, when Venus passes across the face of the Sun as seen from Earth. The next one is due on Tuesday 8 June, which provides the peg for Peter Aughton's biography of Horrocks.

Since Horrocks died in 1641, aged only 22, the material for a biography is thin indeed. In order to stretch his book even to a modest 200 pages, Aughton has been forced to include a lot of rather tedious material about the roots of astronomy in ancient Greece, and student life in Cambridge in the first half of the 17th century. All this, plus some more padding going into far more detail than necessary about Horrocks's work on the orbit of the Moon, rather swamps the central character.

This is a pity, because Jeremiah Horrocks really did do something special. His observation of the transit of Venus was not just a chance to see a spectacular event, but also enabled him, using the geometry of planetary orbits, to work out the first reasonably accurate estimate of the distance from the Earth to the Sun.

And in his lunar work, he was the first to realise that the Moon's orbit around the Earth is elliptical, like the orbits of the planets around the Sun. More by luck than judgement, but demonstrating a willingness to embrace new ideas, Horrocks also came up with the idea that Earth, far from being the centre of the Universe, is not even the largest planet in the solar system, but is dwarfed by Jupiter and Saturn.

None of these ideas had very much influence on the development of astronomy, because of Horrocks's early death, the fact that he worked in the north-west of England away from the mainstream of early science in Britain, and the turmoil caused by the Civil War. When his work was rediscovered in the 1660s, it was no longer revolutionary but fitted in to the developing view of the universe.

Aughton's attempts to set all this in context do not always succeed, and suggest a certain carelessness. He refers to Tycho Brahe as "the last of the naked-eye astronomers", ignoring the claims of Johannes Hevelius, even though Aughton accurately describes the key role played by Hevelius in the rediscovery of Horrocks's work. He also displays a touching naïveté for a historian when he suggests that Francis Bacon "knew something about Horrocks's part of the country, for he represented Liverpool in parliament from1588 to 1594". It was, alas, no prerequisite of service as an MP in the days of Elizabeth I to know anything about your "constituency".

In the end, the book disappoints because Aughton fails to convince me that, as he puts it in the subtitle, Horrocks was "the father of British astronomy". He also rather shoots himself in the foot by ending his account with Newton's quote about "standing on the shoulders of giants", and suggesting that Horrocks was one of those giants.

Newton made that remark in the context of his work on light, long before he published his ideas on gravity and planetary motion, so Horrocks could not possibly have been among the people he was referring to.

No account of Horrocks's life could really be satisfactory, given the paucity of detail available. But this one is less satisfactory than it could - and should - have been, and not up to the standard of entertainment provided by the same author's account of Captain Cook's first voyage in the Endeavour.

John Gribbin is the author of 'Science: a history' (Penguin)