We don't know for sure how many solar systems are in our galaxy. Astronomers have discovered thousands of exoplanets (planets outside our solar system), but that's only a tiny fraction of what's likely out there.

Here's what we do know:

* The Milky Way is HUGE: It's estimated to contain hundreds of billions of stars.

* Planets are common: Astronomers now believe that most stars have at least one planet orbiting them.

* We're still discovering new planets: New exoplanets are being discovered all the time, thanks to powerful telescopes and new detection methods.

So, while we can't give you a precise number, it's safe to say that there are likely billions of solar systems in the Milky Way galaxy.