1)   AstroGrav (Windows) 1.2.2 A software program that allows you to study how astronomical objects move and interact under the force of gravity. It features superb interactive 3D graphics which allow you to move around within an astronomical system, while watching how it evolves. 2)   AstroGrav (Mac) 1.2.2 A software program that allows you to study how astronomical objects move and interact under the force of gravity. It features superb interactive 3D graphics which allow you to move around within an astronomical system, while watching how it evolves.