In case you missed it - here’s the full #MercuryTransit. For more than seven hours today, Mercury was visible as a tiny black dot crossing the face of the sun. This rare event – which happens only slightly more than once a decade – is called a transit. Although Mercury whips around the sun every 88 days – over four times faster than Earth – the three bodies rarely align. Because Mercury orbits in a plane 7 degrees tilted from Earth’s orbit, it usually darts above or below our line of sight to the sun. As a result, a Mercury transit happens only about 13 times a century. The last one was in 2006, and the next one isn’t until 2019.