The history of our exploration of the Transit of Venus, the astronomical phenomenon that helped us to understand the Earth’s place in the solar system, is revealed today in an exciting new online resource launched by the Royal Society. 

The Transit of Venus is the journey of Venus across the face of the sun as visible from Earth.  Observations of the phenomenon, produced by various expeditions around the world starting in the eighteenth century, were used to calculate the Earth’s distance from the Sun and thus inform our understanding of our solar system.  The new resource from the Society illustrates the history of our studies of the Transit of Venus, using material from our archives to allow members of the public from around the world to explore its history.


Image credit: Astroblue

The new resource features an interactive map of the transits, highlighting expeditions and giving access to new, electronic versions of letters, papers, diagrams and paintings stored away in the Society’s archives.

Martin Rees, former President of the Royal Society and Astronomer Royal, said: “Next week there will be a Transit of Venus, an infrequent phenomenon that has been historically of great astronomical importance, and which always attracts wide public interest.  The archives of the Royal Society document the extraordinary evolution of our scientific understanding of our place in the universe and the role of Fellows of the Royal Society and their friends and colleagues over the last few hundred years in elucidating it through the study of the Transits of Venus.  Members of the public can explore the voyages and investigations of scientists and explorers such as Edmund Halley and Captain James Cook, learning about both their pioneering scientific work and their extraordinary adventures at sea.”

The initial importance of the Transit of Venus was first highlighted by English astronomer Jeremiah Horrocks, who died at just 22 years of age, his papers unpublished.  However, some of the founder members of the Royal Society became aware of his work and ensured its publication in the 1660s and 1670s.  Later, another Fellow of the Royal Society, Edmund Halley (now famed for his prediction of Halley’s Comet), began work on the transit, pleading for expeditions to observe the transit in 1761 in the journal, Philosophical Transactions of the Royal Society.  The Royal Society enthusiastically took up the challenge, organising and sponsoring expeditions around the world, including that of Mason and Dixon who ended up voyaging to Cape Town after an attempt to reach Sumatra failed following a French ambush. 

The following transit in 1769 was also carefully followed by the Royal Society.  The most renowned of its expeditions was that of Fellow of the Royal Society Captain James Cook to Tahiti on HMS Endeavour.  Captain Cook and astronomer Charles Green made highly successful observations that were later published in the Society’s journals.  Further expeditions involving Fellows of the Royal Society were organised in the nineteenth century to locations as far afield as Honolulu and Kerguelen in the Indian Ocean in 1874 and the West Indies, Australia and Madagascar in 1882.   

Details of all of these historical tales and the original archive materials can be found in the new online resource

This year’s Transit of Venus (5-6 June) will be best viewed from the Pacific region, however the final hour of the transit will be observable in the UK just after sunrise on 6 June.  The Transit of Venus phenomenon is rare, with two transits appearing with a gap of eight years between them, followed by a longer gap of 121.5 or 105.5years. 

The Transit of Venus should not be viewed by the naked eye.  Further information on how to observe the transit safely can be found on NASA’s website.

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