Why is space dark if stars are bright?

Answer: Stars are too far apart

Stars are too far apart ✓ — Correct! Although there are billions of stars, they're incredibly far apart. Space is about 99.9999999999999% empty vacuum. Light from stars spreads out in all directions, getting dimmer with distance. Most light from distant stars is too faint to see. Also, the universe has a finite age (13.8 billion years), so light from the most distant stars hasn't reached us yet. The vast emptiness between stars makes space appear dark.

There aren't enough stars — Wrong. There are hundreds of billions of stars just in our galaxy alone, and billions of galaxies in the observable universe. The number of stars is enormous. The darkness comes from their vast separation and the finite age of the universe, not insufficient quantity.

Dark matter blocks light — Wrong. Dark matter doesn't block or absorb light - it doesn't interact with light at all, which is why it's called 'dark.' Dark matter only interacts through gravity. The darkness of space is due to the vast distances between stars and limited observable universe.