12 April 1633 and 12 April 1961. Two days on which science challenged the conventional view of our place in the universe: April 12, 1633 when Galileo stands trial for heresy for claiming the sun and not the Earth is the centre of the known universe, and exactly 328 years to the day later (1961) when Soviet cosmonaut Major Yuri Gagarin steps from the Earth into space.
