3D nuclear explosion simulator — true scale
GROUND//ZERO lets you choose any place on Earth, pick a weapon from the 20-ton Davy Crockett to the 50-megaton Tsar Bomba, and watch the detonation unfold in 3D over real satellite imagery, real terrain and real OpenStreetMap buildings. Effects are computed from the empirical scaling laws of Glasstone & Dolan, The Effects of Nuclear Weapons (1977).
1. Blast (Hopkinson–Cranz)
R(ΔP) = R₁(ΔP) · Y^(1/3)
Overpressure radii scale with the cube root of yield. Buildings collapse as the shock front reaches them: flattened inside 20 psi, partially down to 5 psi.
2. Shock front & sound
Sedov–Taylor → Mach 1 (c₀ = 340 m/s)
The sound reaches the camera with its real delay: first the light, then silence, then the blast and a long rolling thunder.
3. Fireball & mushroom cloud
R_fb = 60·Y^0.4 m · t₂max = 0.042·Y^0.44 s
Raymarched volume: blackbody fireball, buoyant rise into a toroidal vortex, dust stem and base surge, Wilson condensation shell.
4. Sources
- Glasstone & Dolan (1977), The Effects of Nuclear Weapons, 3rd ed.
- Brode (1955), Numerical Solutions of Spherical Blast Waves.
- Wellerstein, NUKEMAP.
Frequently asked questions
How far does the blast of a Hiroshima-size bomb reach?
For a 15 kt airburst (Little Boy), the model gives a 177 m fireball, total destruction (20 psi) out to 538 m, collapse of residential buildings (5 psi) out to 1.2 km, third-degree burns out to 2.1 km and broken windows (1 psi) out to 3.1 km. The mushroom cloud tops out around 13 km.
And a modern strategic weapon?
A 1.2 Mt B83 airburst reaches 5.2 km for 5 psi and 12.6 km for third-degree burns; its cloud climbs to about 34 km. The 50 Mt Tsar Bomba gives a 4.5 km fireball, 17.9 km for 5 psi, burns out to 54 km and a cloud about 65 km high.
Why does the sound arrive after the flash?
Light is instantaneous at these distances, but the shock wave travels at about the speed of sound: 20 km away, the blast arrives roughly a minute after the flash. The simulator reproduces that delay.
Is it accurate?
Radii follow published scaling laws; casualties use a simplified population-density model. It is an educational visualisation, not a planning tool.
Open source (MIT): github.com/albedo83/ground-zero
Map data: Sentinel-2 cloudless (EOX), AWS Terrain Tiles, OpenFreeMap / OpenMapTiles © OpenStreetMap contributors.