Interactive
Strange Skies
Every object here hangs exactly where the Moon or the Sun hangs, drawn at its true size in our sky. The telephoto frame spans about 9 degrees; switch to the wide view for the full 90. Swap the sky.
This is the visual companion to the What-If Lab, where the same impossibilities get argued in physics. Then plan the trip with the Space Travel Calculator, and check the real sky with Sky Tonight.
Under the hood
The honest scale
Every size on this page is exact relative to the others. Night objects hang at the Moon's mean distance, 384,400 km from Earth. Day objects sit at 1 AU, the Earth-Sun distance. The telephoto frame spans about 9 degrees of sky and the wide frame spans 90, and each object is drawn to the same scale in both, so a world that overflows the telephoto frame really would overflow that patch of sky.
One element is representative rather than to scale: a ten-solar-mass black hole's event horizon is 59 km across, which at the Moon's distance would be an invisible speck. Its accretion disk is drawn large enough to see, sized to suggest the real glow of infalling gas rather than to measure it. The photon ring and the shadow at its heart are drawn to match.
Brightness is artistic licence. Venus really would be dazzling and a blue supergiant really would be blinding, but no screen can reproduce either. The sizes are the honest part.
Common questions
What would Saturn look like if it replaced the Moon?
Saturn's globe would span 17.2 degrees of sky, about 33 times wider than the Moon, and its rings would stretch 39 degrees. It would dominate the night completely. This page draws it at exactly that scale.
How big would Jupiter look at the Moon's distance?
About 20.6 degrees across, roughly 40 times the Moon's width. Its cloud bands and the Great Red Spot would be visible to the naked eye, with its four large moons nearby as bright companions.
Are the sizes on this page accurate?
Yes, relative to each other. Night objects hang at the Moon's mean distance of 384,400 km and day objects at 1 AU, all drawn to one scale. The single exception is a black hole's accretion disk, drawn at a representative size because the hole itself, at 59 km wide, would be an invisible speck.
Could a black hole really sit where the Moon is?
Only as a thought experiment. A ten-solar-mass black hole that close would pull on Earth with the gravity of ten Suns and bathe the planet in radiation from its disk. Strange Skies is a viewing exercise, not a survival plan.