Approximately 150 globular clusters orbit the Milky Way. These clusters are ancient, tightly bound spheres of stars that travel mainly through the galaxy’s extended halo rather than lying in its thin, star-forming disk. The number is an estimate because dust and crowded regions near the galactic plane can hide faint or distant clusters, and new surveys continue to identify previously missed examples.
Most Milky Way globular clusters contain very old stars, commonly around 10 to 12 billion years old. Their ages and chemical compositions provide clues about the early formation of the galaxy. Some clusters also move on unusual or retrograde orbits, suggesting that the Milky Way captured them from smaller galaxies during past mergers.
The figure is sometimes given as about 150 known clusters, while broader estimates can reach 150–200 when likely undiscovered objects are included. That uncertainty does not make answers such as 300 or 500 standard estimates. The total also changes as surveys improve, so “approximately 150” is the conventional quiz answer rather than a permanent exact count.