Shireen Gonzaga is a freelance writer who enjoys writing about natural history. She is also a technical editor at an astronomical observatory where she works on documentation for astronomers. Shireen has many interests and hobbies related to the natural world. She lives in Cockeysville, Maryland.
An image of craters on Mercury obtained during MESSENGER’s second fly-by. The largest crater at the top of the image, named Polygnotus, has a diameter of 133 km (83 miles). Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.