A collection of stars orbiting a common center of mass. Open clusters typically contain a few hundred stars and may be only 100 million years old or even less. Globular clusters may contain up to a million stars, and most are at least 10 billion years old (almost as old as the universe itself).
Mars Express achieves 25,000 orbits
Mars Express achieves 25,000 orbits by Erica Marchand Paris, France (SPX) Mar 28, 2024 Celebrating a significant milestone, ESA's Mars...