Black Hole Sandbox

A realistic black hole, in the palm of your hand. Black Hole Sandbox gives you a scientifically accurate black hole, ray-traced live on your iPhone. It traces light through curved spacetime using the equations of general relativity: light that comes too close falls into the shadow, and light that passes nearby bends around it. The galaxy behind stretches into arcs, the far side of the disc lifts above and below the shadow, and a thin ring of photons wraps its edge. Orbit it, zoom in, and watch the light bend as you move around it in real time. TWO WAYS TO SEE IT • In-app 3D: set it against a whole galaxy or a field of stars, and watch the lensing bend everything behind it as you orbit around it. • In augmented reality: the star of the show! Put it in your living room, sit it on a table, and walk around it as it warps your room behind it. DESIGN YOUR OWN Go beyond realism and lets see your creativity! • Shape and light: start grounded. Set the size of the shadow, how bright the photon ring burns and how far its glow reaches, the gap and width of the accretion disc, its tilt, and how brightly it glows. • Color: then dial it up a notch. Choose from 37 palettes of single and dual color combos, or pick your own inner and outer colors. • Texture: wrap the disc in 14 dynamic textures, from smooth swirls and drifting wisps to bands, clumps and cells. Set their strength and detail, spin the disc faster or slower, and add wind to curl the swirls tighter toward the center. • Facets: break the disc into 14 geometric patterns, like triangles, diamonds, scales, spirals and gems, then set the size of the cells and how fast they turn to create a shimmer. • Emojis: feed it your favorite emojis and watch a swarm of them orbit the shadow, glowing as they go. Change their size, density, and how they tumble. • Photos: make one of your own photos the accretion disc and watch it spin around the abyss. Twelve presets come built in to get you started, and you can save as many of your own as you like. Build either realistic black hole or one that could never exist, then set it on your coffee table.