Neptune at closer distances
Neptune is the most distant planet in the Solar System and has never been seen as anything but a point without a telescope. It is also the deepest blue object Perigee renders. Moving it inward is the clearest demonstration that distance, not size, is what keeps most of the Solar System invisible.
- 49,244 km
- 16.11 hours
- planet
How big does Neptune actually look from Earth?
At 28.7 AU, Neptune spans 2.36 arcseconds across your sky — a small fraction of the width of the full Moon. Light crosses that gap in 4.0 hours.
At its real distance Neptune is not visible to an unaided eye at all.
How big would Neptune look if it replaced the Moon?
At 384,400 km, Neptune spans 7.3° across your sky — about 14 times the width of the full Moon. Light crosses that gap in 1.3 seconds.
At the Moon's distance Neptune is far the wider of the two, and a deep, even blue.
How big would Neptune look from a hundredth of an astronomical unit?
At 1,495,979 km, Neptune spans 1.9° across your sky — about 3.6 times the width of the full Moon. Light crosses that gap in 5.0 seconds.
The faint banding in the atmosphere becomes readable.
How big would Neptune look from a tenth of an astronomical unit?
At 14,959,787 km, Neptune spans 0.2° across your sky — about 0.36 times the width of the full Moon. Light crosses that gap in 49.9 seconds.
Neptune brought closer than Earth ever is to the Sun.
How big would Neptune look at one astronomical unit?
At 149,597,871 km, Neptune spans 0.02° across your sky — a small fraction of the width of the full Moon. Light crosses that gap in 8.3 minutes.
Neptune where Earth sits.
What Perigee calculates and what it renders
The apparent size on this page is calculated from the published diameter and the distance you choose, using the same geometry the live scene uses. The lighting and surface treatment are an authored visualization.
How Perigee calculates apparent size