51: Mercury in Transit!

On 11 November, the littlest planet Mercury wandered bravely across the face of the Sun — and all over the world people watched it happen through their telescopes and solar filters. Chris and Emily went our on a cold, windy Yorkshire autumn afternoon to the University of York's Astrocampus — Emily's second home. They caught a brief but satisfying glimpse of tiny Mercury silhouetted against the giant solar disc, and chatted about transits, what they mean, and what we learn from them.