There's always pi! Craters can tell scientists a lot about the surfaces of planets, moons and other bodies. Just by determining how circular a given crater is – using pi and the crater’s perimeter and area – planetary geologists can reveal clues about how the crater was formed and the surface that was impacted. Each year across the globe, people celebrate Pi Day. On March 14 (3/14 in the month/day date format), since 3, 1, and 4, or 3.14, are the first three significant digits of π, we sing the praises of this mathematical constant. Here at NASA, whether it's sending spacecraft to other planets, driving rovers on Mars, finding out what planets are made of or how deep alien oceans are, pi takes us far. Happy Pi Day! Image Credit: NASA #piday #pi #π #nasa #crater #space #planet #world #terrain #picoftheday #pictureoftheday #astronomy #science #math #mathematics #school