Science and Nature Quiz for 21 October 2015

A new science quiz is available each week. Try our daily general knowledge quiz or work through our archive of daily and themed quizzes.

Question 1: Until 1965, it was thought that which planet was synchronously tidally locked with the Sun, rotating once for each orbit and keeping the same face directed towards the Sun at all times, in the same way that the same side of the Moon always faces the Earth?