NASA image: Mercury transit

On May 9, 2016, Mercury passed directly between the sun and Earth.

This event – which happens about 13 times each century – is called a transit.

NASA's Solar Dynamics Observatory, or SDO, studies the sun 24/7 and captured the entire seven-and-a-half-hour event.

This composite image of Mercury's journey across the sun was created with visible-light images from the Helioseismic and Magnetic Imager on SDO.

Read more: Little Mercury a black dot as it crosses vast face of sun—sun.html" target="_blank">phys.org/news/2016-05-mercury- … t-sun.html