On this week's Science Weekly, Guardian science correspondent Ian Sample learns about the extraordinary and unprecedented international scientific collaboration that was organised to measure the transit of Venus in the 18th century.

Historian Andrea Wulf discusses her book Chasing Venus: The Race to Measure the Heavens, which documents the collaboration required to observe and track the 1761 and 1769 transits.

The next transit takes place on 5 and 6 June, and there won't be another along until 2117. For more information on how you can track the transit and for a live feed go to Nasa's dedicated website.

Observer science editor Robin McKie joins us to discuss the legacy of science writer Rachel Carson on the 50th anniversary of the publication of her book Silent Spring. Robin and other Observer writers will be speaking at this year's Bristol Festival of Ideas.

Finally, the Guardian's environment editor John Vidal talks to barrister and campaigner Polly Higgins about her attempt to add the crime of ecocide to the four internationally accepted crimes against humanity.

Polly, who will speak at the forthcoming How The Light Gets In festival at Hay-on-Wye, discusses the legal definition of ecocide and why the Earth and its inhabitants need such a legal framework to defend them.

Subscribe for free via iTunes to ensure every episode gets delivered. (Here is the non-iTunes URL feed).

Follow the podcast on our Science Weekly Twitter feed and receive updates on all breaking science news stories from Guardian Science.

Email scienceweeklypodcast@gmail.com.

Guardian Science is now on Facebook. You can also join our Science Weekly Facebook group.

We're always here when you need us. Listen back through our archive.