Earth (and the solar system) is moving through the Milky Way’s disk in a stable, roughly circular orbit around the galactic center. The latest astronomical measurements indicate that our orbital velocity around the center of the Milky Way is about 450,000 miles per hour (200 kilometers per second). That is almost a thousand times the cruising speed of most commercial jetliners. Even so, the Milky Way is so huge that one complete orbit takes about 250 million years.