What is the Mercury Transit? A local expert explains

(Jackson, Wyo.) - Today, there is a Solar Astronomy event called the Transit of Mercury. While several people are talking about this event, we asked a local expert on what is actually happening in the sky. "Much like an eclipse, occasionally Mercury will pass directly between the Earth and the Sun. Called a transit, the last time this happened was in 2006. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit (there is a 7 degree angular difference), Mercury usually appears to pass over or under the Sun, making this morning's transit somewhat rare. The next time a transit like this will happen is in 2019," Ryan Hennessy, Astronomer for Four Seasons Resort and Residences Jackson Hole. "An interesting note about the image is that Mercury is actually much closer to us than the image suggests. Specifically, the Sun is so big that you could line up more than 109 Earths across its face. Each one of those lined-up Earths would be smaller than the large sunspots at top left! Imagine what it would look like, then, if you could stand on the surface of the sun and witness an Earth-sized column of flame like we see on the Sun's left-most edge," said Hennessy. More information on the Mercury Transit is available here. *Feature Photo: h/t **edhiker ( ) [CC BY 2.0 ( ], via Wikimedia Commons** /