The Andromeda Galaxy at closer distances
Andromeda is the surprise on this site. At its true distance it already spans several times the width of the full Moon — it is simply too faint for most eyes to separate from the sky around it. Every step of its ladder moves it through the Local Group rather than the Solar System, because a galaxy has no useful planetary distance.
- 1,305,580,805,216,150,500 km
- galaxy
How big does the Andromeda Galaxy actually look from Earth?
At 2,500,000 ly, the Andromeda Galaxy spans 3.2° across your sky — about 6.1 times the width of the full Moon. Light crosses that gap in 2,500,000 years.
The real sky, at the real distance. The disc is already several full Moons wide, and almost nobody has seen it that way.
How big would Andromeda look from one million light years?
At 1,000,000 ly, the Andromeda Galaxy spans 7.9° across your sky — about 15 times the width of the full Moon. Light crosses that gap in 1,000,000 years.
The spiral structure separates from the bulge.
How big would Andromeda look on a Local Group approach?
At 500,000 ly, the Andromeda Galaxy spans 15.7° across your sky — about 30 times the width of the full Moon. Light crosses that gap in 500,000 years.
A Local Group approach.
How big would Andromeda look from inside its halo?
At 250,000 ly, the Andromeda Galaxy spans 30.9° across your sky — about 60 times the width of the full Moon. Light crosses that gap in 250,000 years.
Crossing the outer halo.
How big would Andromeda look with the two discs nearly touching?
At 150,000 ly, the Andromeda Galaxy spans 49.4° across your sky — about 95 times the width of the full Moon. Light crosses that gap in 150,000 years.
The two discs nearly meet. Nothing here endangers Earth.
What Perigee calculates and what it renders
The apparent size is calculated from catalogued geometry. The structure you see is drawn procedurally at that size rather than simulated, and no physical interaction is modelled.
How Perigee calculates apparent size