Next in this series →
Scale of the universe ↗
Cosmic zoom from Earth to the observable universe.
Universe · Question
Is a light-year a measurement of time or distance?
Despite the word "year," a light-year measures distance: how far light travels in one Earth year, about 9.46 trillion km. Pick a star below to see what year its light actually left.
Visual model
When did that light leave?
Measurable fact
The distance ladder.
- 1.3 light-secondsEarth to the Moon
- 8.3 light-minutesEarth to the Sun (1 AU)
- ~4.1 light-hoursEarth to Neptune
- 4.25 light-yearsTo Proxima Centauri, the nearest star to the Sun
- ~26,000 light-yearsEarth to the center of the Milky Way
- ~2.5 million light-yearsTo the Andromeda Galaxy, the nearest large galaxy
Misconception check
Quick check.
Quick check
Go deeper
Keep exploring.
Universe
How big is the universe?
Zoom out from Earth to the observable universe.
Home
Solar system model
Back to the interactive 3D solar system.