* We can only see a tiny fraction: Even with the most powerful telescopes, we can only see a tiny fraction of the stars in the observable universe. The vast majority are too faint or too far away to detect.
* Constant discovery: Astronomers are constantly discovering new stars through surveys and observations.
* Different definitions of "know": Do we mean stars we've individually cataloged and studied, or simply stars that we know exist within certain galaxies or regions of space?
Here's what we *do* know:
* Our galaxy: The Milky Way galaxy is estimated to contain around 100 billion stars.
* The observable universe: Estimates for the number of stars in the observable universe range from 10^22 to 10^24 (that's 10 followed by 22 or 24 zeros!).
In short, we know of a huge number of stars, but the true number is beyond our current ability to count.
