This event will explore the phenomenon of planetary occultations of Mercury, when Mercury passes between Earth and the Sun, blocking out the Sun's light from view. Participants will learn about the history of these events, how they are observed, and what they can tell us about the planet Mercury. Additionally
From Wikipedia
In astronomy, planetary transits and occultations occur when a planet passes in front of another object, as seen by an observer. The occulted object may be a distant star, but in rare cases it may be another planet, in which case the event is called a mutual planetary occultation or mutual planetary transit, depending on the relative apparent diameters of the objects.