Cosmos

Live site: https://protonmatter.github.io/cosmos/

A landing page, three presentation decks on the solar system — the planets, the moons, and JunoCam — the JunoCam explorer and poster, and a beta iOS prototype called the Pocket Planetarium. Built as standalone HTML: no build step and nothing to install. Open any file in a browser, or serve the folder.

index.html is the interactive landing page. It links every deck, the beta preview, and on to Sol.

What's here

File	Format	What it covers
index.html	landing	Showcase page for the collection, with links to the beta and through to Sol
solar-system.dc.html	13 slides	The Sun, the eight planets and the Moon — one card each, with radius, mass, gravity, rotation, tilt, temperature, atmosphere and field strength
the-moons.dc.html	18 slides	Twenty-two moons across five systems: Mars, the Galileans, Saturn's ice moons and Titan, the Uranian five, Neptune's three
junocam-deck.dc.html	11 slides	JunoCam itself: the instrument, why its images arrive as raw strips, and the volunteers who process them
junocam-explorer.dc.html	interactive	The thirty processed Jupiter frames, filterable by region and treatment, with a zoomable viewer and a side-by-side compare mode
junocam-poster.dc.html	18 × 24 in	A single printable sheet on the same subject
beta.html	landing	Preview page for the beta, introducing the Pocket Planetarium
pocket-planetarium.html	beta / iOS	A scroll-driven journey from the Sun out to Neptune, with the moons and the JunoCam gallery below

The decks are 1920 × 1080 and scale to fit the window. The poster prints at 18 × 24 inches.

The pages are plain HTML that declare their content declaratively; support.js, deck-stage.js and deck-cinema.js provide the slide runtime, and classical.css the shared look.

Pocket Planetarium (beta)

An early iOS prototype of Cosmos as a single scrollable app: the Sun, eight planets, twenty-two moons and the thirty JunoCam photographs. beta.html introduces it and, on a desktop browser, presents it inside a simulated 390 × 844 device frame:

On an iPhone, open pocket-planetarium.html full screen instead for the intended experience:

Its assets live under beta/pocket-planetarium/. This is a prototype, not a release — the decks are unaffected by anything in it.

Using them

Open a file directly, or serve the folder:

python3 -m http.server 8000

then visit localhost:8000/ for the landing page (or any file above).

Arrow keys or space advance the decks. Print to PDF gives one page per slide.

Development

The site has no build step and never will — the pages open straight from the filesystem. The tooling below tests the site; it does not build it, and nothing it installs is served or deployed.

npm install
npm run serve   # http://localhost:8000
npm test        # validation, traceability, functional, e2e, regression

Substantive changes are proposed as an RFC, specified as numbered requirements in docs/specs/, and covered by tests that name the requirement they discharge. docs/SDLC.md walks through the whole path from idea to production, and CONTRIBUTING.md has the practical detail.

Publishing on GitHub Pages

.github/workflows/pages.yml deploys the repo root on every push to main (Settings → Pages → Source: GitHub Actions), but only after the same quality gate that guards pull requests has passed. If the gate is red the live site is left untouched.

React, ReactDOM and Babel are vendored under vendor/, so the decks, the explorer, the poster and the landing page carry no CDN dependency and work offline; only the Google Fonts stylesheet is fetched remotely. The one exception is the Pocket Planetarium prototype, which is served by a separate copy of the runtime that still loads React and Babel from unpkg — recorded as deviation D-1 in docs/specs/site.spec.md.

Where the numbers come from

Every figure in the decks is read from the body and satellite tables in Protonmatter/sol — apps/web/js/bodyData.js and apps/web/js/moons.js — which cite the NASA Planetary Fact Sheets and IAU WGCCRE 2015 (Archinal et al. 2018) for radii and rotation. The descriptive text is that project's own, unchanged.

Each deck ends with a sources slide giving per-image provenance.

Image credits

Spacecraft imagery is NASA/JPL-Caltech and partner institutions, in the public domain:

• Sun and planets — SDO (Sun), MESSENGER (Mercury), Magellan (Venus), DSCOVR (Earth), Viking (Mars), JunoCam (Jupiter), Cassini (Saturn), Voyager 2 (Uranus, Neptune)
• Moons — Voyager 1 and 2, Galileo, Cassini–Huygens, Juno, Mars Reconnaissance Orbiter
• Jupiter and Io frames (images/) — JunoCam raw data processed by volunteers, from the Mission Juno citizen-processing gallery (NASA/JPL-Caltech/SwRI/MSSS)

Two files are not public domain and are used under CC BY 4.0: textures/moon.jpg and textures/saturn_ring.png, from Solar System Scope, which composites NASA source data.

Some small or distant moons are shown as enlarged crops of low-resolution frames — Nereid especially, which Voyager 2 resolved to only a few dozen pixels. The sources slides say which.

Typography is Cormorant Garamond and Lora, both under the SIL Open Font License.

Licence

Deck code and layout: MIT, see LICENSE. Imagery and figures keep the terms above; MIT does not extend to them.