gcdatlas

The real universe, drawn entirely in ASCII.

gcdatlas is an explorable atlas of the known universe where every frame is made of printable ASCII characters. Planets are where they are today, about 2,000 naked-eye stars sit at their measured distances, every active satellite circles the Earth, and one continuous zoom takes you from a city street's worth of sky to the edge of the observable universe.

• Denser glyphs mean more light. Colour comes from the physics: blackbody temperature, Doppler shift, emission lines.
• Black holes bend light (Schwarzschild ray tracing) above the true shape of their curved space (Flamm's paraboloid). Galaxies collide, binary stars trade gas, a star is torn apart, two black holes merge and ripple spacetime.
• The Halo, a long-range cruiser with a captured star for a heart, is the one invented thing here. Ride along behind it, or from its bridge.

How accurate is it? positions, distances and sizes are real; the look of each object is a physically based artist's rendering.