periapsis
pl: periapses
Related Words
apoapsisperigeeperihelionorbitellipseeccentricitygravityastronomyastrophysicscelestialsatelliteplanetstarmooncometasteroidmeteortrajectoryvelocityaccelerationmomentumnewtonapogeeaphelionfocusorbitalperiodprecessionperturbationvacuumspacecosmosuniversemassinertiacentripetalcentrifugalcurvaturearcvertexnodeinclinationazimuthzenithnadirparallaxlight yearastronomical unitblack holesingularityevent horizongeodesicrelativityspacetimetideoscillationresonanceescape velocityfree fallballisticspropulsiontelemetryephemerissidereal