Last year, NASA's Messenger mission gave us the first up-close view of parts of Mercury, the planet closest to the Sun. The spacecraft has found extensive ridges along the planet's surface ...

This image shows Mercury as a small black dot moving across the face of the Sun during its rare transit on May 9, 2016.  This image shows a gravity map of Mercury created using data from NASA’s ...

As Venus and Mercury exit the stage, a few remnants of the "planetary parade" will be visible after sunset. With Saturn already lost in the sun from Earth's point of view as it moves behind the ...

Mercury has the shortest and fastest orbit around the Sun and experiences dramatic temperature changes as it rotates. It is a world of extremes. Explore facts about our solar system's fastest planet.