On a clear, moonless night away from city lights, the sky looks like it's absolutely overflowing with stars. It feels as though there must be millions of them sparkling right above your head. But if you actually took the time to point your finger and count them one by one, the answer would surprise you.
What the Naked Eye Can See
Even under perfectly dark, rural skies, human eyes are limited. Without the aid of a telescope or binoculars, a person with good vision can only see about 4,500 to 5,000 stars at any given time.
Why so few? Because we can only see the stars that belong to our local neighborhood in the Milky Way galaxy, and we can only see the ones bright enough for our retinas to detect.
Zooming Out: The Milky Way
If we look beyond what our naked eyes can see and consider the entire Milky Way galaxy, the numbers become staggering. Our galaxy is a massive spiral city of stars. Astronomers estimate that the Milky Way contains anywhere between 100 billion to 400 billion stars!
If you counted one star every second without ever sleeping, it would take you over 3,000 years to count just 100 billion stars.
The Observable Universe
Our Milky Way is just one galaxy. The Hubble and James Webb Space Telescopes have revealed that the observable universe is packed with galaxies. In fact, astronomers estimate there are up to 2 trillion galaxies in the observable universe.
If we multiply the number of galaxies by the average number of stars in a galaxy, we get the total number of stars. The estimated number of stars in the observable universe is roughly 200 billion trillion (that's a 2 with 23 zeros after it: 200,000,000,000,000,000,000,000).
As astronomer Carl Sagan famously said, there are more stars in the universe than there are grains of sand on all the beaches on Earth.
