The film

Time has one direction. The film follows it from the Big Bang to the heat death of the universe, paced by a ticking clock: it falls silent in the Big Bang, accelerates through human history, stops dead at Now, then resumes and slows as the stars die, until its last tick.

How it was made

• Everything is code. No footage, stock or samples: ray marching, particle sprites and painted silhouettes make every frame, and a small synthesizer makes every sound. The one recording is NASA's own, of Neil Armstrong calling Houston from Tranquility Base.
• Real science and history where it counts. The Moon forms in a smoothed-particle hydrodynamics simulation run for the film (SWIFT, 61,139 particles). Today's Earth comes from Natural Earth maps, and the Big Dipper drifts on its Hipparcos proper motions. The rocket under the 1957 card is the R-7 that carried Sputnik, and Eagle comes down under a Sun ten degrees up, as it did on 20 July 1969.
• One source of timing. film/timeline.json holds the script, the captions and every cue. The shots, the captions and the score all read it, so moving a beat moves the picture, the text and the music together.
• A score you can check without listening. Organ, strings, piano, synth brass, bells, choir and drums with convolution reverb, mastered to -14 LUFS. CI renders it on every push and checks its hits and cuts against the timeline.
• Cinematic post. HDR rendering, bloom, anamorphic streaks, light shafts, ACES tonemapping, grading, grain, motion blur, and a 2.39:1 letterbox that opens to full frame for the biggest moments.
• Renders anywhere. Headless Chromium on a GPU, Mesa llvmpipe on a plain CPU, or dozens of containers at once on Modal for minutes and about a dollar.

The making-of goes scene by scene, and the score explains the music.

Build it yourself

You need Node 20+, Python 3.10+ and ffmpeg (details per platform).

git clone https://github.com/abhishekpradhan/the-arrow-of-time.git
cd the-arrow-of-time
npm install
npm run setup        # Python venv for the score, Playwright's Chromium, ffmpeg check

npm run dev          # interactive preview at http://localhost:5173
npm run audio        # synthesize the score -> out/audio/score.wav
npm run render       # render the film      -> out/renders/the-arrow-of-time-final-latest.mp4

With a GPU the final 1080p render takes about half an hour; on a CPU alone it takes several hours, which is what Modal is for.

What's in this repository

film/      the film: timeline.json (script, captions, cues), project.ts, shots/, shaders/,
           text.ts (captions), score.py (the score)
engine/    the WebGL2 film engine it runs on (TypeScript): renderer, camera, post, text,
           components (planets, galaxies, an atmosphere) and a GLSL library
audio/     the Python synthesizer, mastering and analysis the score is written with
tools/     render, still, audio and release CLIs; the Modal pipeline; asset builders
assets/    data the film loads: Earth maps, the giant-impact simulation, NASA's Apollo 11 audio
docs/      the making-of, the score, and guides to working on, rendering and releasing the film
out/       renders, stills and audio (git-ignored)

timeline.json ──► project.ts ──► shots (GLSL, sprites, ray marching) ──► HDR composite ──► post ──► frame
      │                 └──────► captions (glyph cache, per-beat layout) ─────────────────────┘
      └──────────────► score.py ──► audio/studio synth ──► mix ──► master ──► score.wav ──┐
                                                                                          ▼
                      headless Chromium ──► raw RGBA ──► ffmpeg (x264) ──────────────► film.mp4

Contributing

Notes on the film are as welcome as code: a shot that could be better, a caption that reads wrong, a scientific or historical detail (with a source, ideally). Use the issue forms. Fixes and improvements to the engine, the tools and the synthesizer are welcome too, and so are re-cuts, translations and remixes of the film under its license. See CONTRIBUTING.md, the Code of Conduct and SECURITY.md. Changes are listed in the CHANGELOG.

Credits and license

The Arrow of Time is by Abhishek Pradhan. If it moved you, you can buy me a coffee.

• The film (the video and its soundtrack, stills, and the words it speaks) is licensed under CC BY 4.0. Share it, re-cut it, translate it, remix it, commercially too, with credit: "The Arrow of Time by Abhishek Pradhan, https://github.com/abhishekpradhan/the-arrow-of-time, CC BY 4.0".
• The code, all of it (the engine, the tools, the synthesizer, and the film's shots, shaders and score code), is licensed under the MIT License. Build on it.
• Borrowed with thanks: the Apollo 11 air-to-ground audio, courtesy of NASA (not covered by the film's license); Earth maps from Natural Earth (public domain); star positions from ESA's Hipparcos catalogue; the Moon-forming impact simulated with SWIFT, WoMa and SEAGen; shader and DSP snippets by Inigo Quilez, Dave Hoskins and others (MIT); and the typefaces Cinzel, Jost, Cormorant Garamond and UnifrakturMaguntia (SIL Open Font License). Details are in THIRD_PARTY_NOTICES.md.