How To Watch Mercury's Rare Transit In Front Of The Sun By editor • Nov 8, 2019 ShareTweetEmail In this handout provided by NASA, the planet Mercury is seen in silhouette, lower left, as it transits across the face of the sun Monday, May 9, 2016 Boyertown, Pennsylvania. Mercury passes between Earth and the sun only about 13 times a century, with the previous transit taking place in 2006. (Photo by NASA/Bill Ingalls via Getty Images) Listen Listening... / Mercury crosses in front of the sun on Monday morning in a rare celestial event. Kelly Beatty (@NightSkyGuy), senior editor at Sky and Telescope, tells us how to watch it and what else is happening in the sky right now. This article was originally published on WBUR.org.Copyright 2019 NPR. To see more, visit https://www.npr.org. ShareTweetEmailView the discussion thread.