How big is the observable universe?

The observable universe has a diameter of approximately 93 billion light-years (8.8 × 10²⁶ meters). This may seem paradoxical for a 13.8-billion-year-old universe, but the expansion of space itself means that distant objects have moved much farther away than the light-travel distance suggests. It contains an estimated 2 trillion galaxies (revised upward from 200 billion in 2016), approximately 1 × 10²⁴ stars, and more than 10⁸⁰ atoms. The observable universe is defined by the cosmic light horizon — the farthest distance from which light has had time to reach us since the Big Bang. Beyond this horizon, there is likely more universe that we simply cannot observe. The total universe may be 250× larger than the observable portion — or potentially infinite.