Stars in the Known Universe

Estimating the number of stars in the known (observable) universe is incredibly complex, but here's the best approximation based on current astronomical knowledge:

Estimated Number of Stars:

~1 x 10²⁴ stars
That’s 1 septillion stars — a 1 followed by 24 zeros.

How This Estimate Is Calculated:

1. Galaxies in the Observable Universe:
   Astronomers estimate there are about 2 trillion galaxies (2 x 10¹²).

2. Average Number of Stars per Galaxy:
   A typical galaxy like the Milky Way has 100 billion to 400 billion stars (1 x 10¹¹ to 4 x 10¹¹).

3. Multiply Galaxies by Stars:
   Using average values:

   • 2 x 10¹² galaxies × 1 x 10¹¹ stars = 2 x 10²³ stars

   Adjusting for large galaxies, star clusters, and observational uncertainties, the estimate becomes roughly:

   • 1 x 10²⁴ stars

Important Notes:

• This number only includes stars in the observable universe, not the entire universe, which could be infinitely larger.

• These estimates rely on telescope observations, modeling, and assumptions about galaxies we can't see in detail.