It's impossible to know exactly how many stars there are in the universe. Here's why:

* The universe is vast: We can only see a portion of the observable universe, and it's constantly expanding.

* Stars are constantly forming and dying: New stars are born, and older ones die out.

* Many stars are too faint to see: Even with our most powerful telescopes, we can only detect stars that are relatively close or exceptionally bright.

Estimates:

* Our Milky Way: Scientists estimate that there are about 100 billion stars in our Milky Way galaxy alone.

* Observable universe: There are likely trillions upon trillions of stars in the observable universe.

So, while we don't have a precise number, the universe is absolutely teeming with stars!