An object moving along a path controlled by gravity is said to be in orbit, and there are many different kinds: straight lines, circles, ellipses, parabolae, and hyperbolae.

在引力控制下运动的物体被称为在进行轨道运动，而轨道有许多不同的种类：直线、圆、椭圆、抛物线和双曲线。