We don't know the exact number of planets in the Milky Way galaxy. However, we can make estimates based on observations and models.

Here's what we know:

* Exoplanet Discoveries: Astronomers have discovered thousands of exoplanets (planets outside our solar system) using various methods.

* Planet Occurrence Rate: Studies suggest that on average, stars in our galaxy likely have at least one planet orbiting them. Some estimates put this rate even higher.

* Number of Stars: The Milky Way galaxy is estimated to contain 100-400 billion stars.

Estimates:

Based on these factors, scientists estimate that the Milky Way galaxy could contain anywhere from 100 billion to 1 trillion planets.

Important Note: These are rough estimates, and the actual number could be higher or lower. Our understanding of planet formation and detection methods is constantly evolving.