Nowadays it is so easy to find new planets that a teenager can do it in his third day of intership at NASA. However, back in the day things were a little more complicated. There were no  fancy devices and advanced technology, so they had to make-do with other things, like using Venus to know how far the Earth is from the Sun. Join us to learn how they did it in this week´s episode! -- Sources: Hannah Morrison (2020): Meet the NASA intern who discovered a new planet on his third day. BBC News. / David Shortt (2012): Some Details About Transits of Venus. The Planetary Society. / Tim Sharp (2018): Edmond Halley: An Extraordinary Scientist and the Second Astronomer Royal. Space. / Tim Sharp (2021): How far is Earth from the sun? Or: What is an astronomical unit? Space. / Peter Aughton (2002): Endeavour: The Story of Captain Cook's First Great Epic Voyage. London: Cassell & Co.