# Credits

## Web font

The HTML export uses Noto Sans Math as a fallback for arrows and physics symbols.
Copyright 2022 The Noto Project Authors (https://github.com/notofonts/math).
Licensed under the SIL Open Font License 1.1. The license is included in
`godot/assets/fonts/OFL.txt` and as `FONT-LICENSE.txt` in the web export.
Source: https://github.com/google/fonts/tree/main/ofl/notosansmath

## Game-tile illustrations

The "luminous on dark" artwork on each game tile (`godot/scripts/ui/GameArt.gd`) is
**original work**, drawn procedurally at runtime with Godot's 2D `_draw()` API — no
external image assets, fonts, or third-party art are used.

## Sound effects

All sound effects (`godot/scripts/Sfx.gd`) are **original**, synthesized procedurally in
code at startup — sine/square/saw tones, frequency sweeps, and low-pass-filtered noise
bursts shaped by an attack/release envelope. No audio files, samples, or third-party sound
assets are used. The in-game particle bursts likewise use a code-generated radial texture,
not an image file.

## Scientist photographs

The game tiles and the Solvay Quiz show stylized (cartoon) portraits of the physicists
(`godot/assets/scientists/*.jpg`). Clicking a portrait in the quiz opens the corresponding
**real historical photograph** (`godot/assets/scientists/originals/*.jpg`). These are
early-20th-century portraits of the 1927 Solvay generation, in the public domain in their
countries of origin and the United States by virtue of their age. Operators should confirm
the licensing status that applies to their own use before public display.

## 1927 Solvay Conference photograph

The reference photo in "Spot the Scientist"
(`godot/assets/solvay/solvay_1927.jpg`) is the famous group photograph of the
Fifth Solvay International Conference on Electrons and Photons, Brussels, October
1927, by **Benjamin Couprie** (Institut International de Physique Solvay). It is
in the **public domain**: the image was published in Belgium more than 70 years
ago. Sourced from Wikimedia Commons
(*File:Solvay conference 1927 (group photograph).jpg*), downscaled for display.
Operators should confirm the licensing status that applies to their own use
before public display.

## Difficulty-tier icons

The physics-content difficulty badges on the game cards
(`godot/assets/difficulty/baby.png`, `teen.png`, `grad.png`) are from
**Twemoji** (baby U+1F476, child U+1F9D2, graduation cap U+1F393).

> Twemoji © Twitter, Inc. and other contributors. Licensed under
> **CC-BY 4.0** (https://creativecommons.org/licenses/by/4.0/).
> Source: https://github.com/jdecked/twemoji

## Star imagery (Black-Body Furnace)

The Black-Body Furnace can show a short looping animation of the current target
star, played from a sprite-sheet (`godot/assets/stars/<id>.png`) generated from
source media by the repo-root `make_star_sheets.py` tool. The bundled star media
below is all **public-domain or CC-BY**; when a file is absent the game falls back
to a fully procedural glowing star (`godot/scripts/ui/StarView.gd`, 2D `_draw()`),
so nothing external is required to run.

- The **"YOUR FURNACE"** star is always procedural (drawn at runtime), recoloured
  live from the dial temperature. No external asset.
- **Sun:** the bundled loop (`godot/assets/stars/sun.png`, built from
  `godot/assets/stars/source/sun.gif`) is **NASA SDO AIA 171 Å** imagery
  (Solar Dynamics Observatory, 2011-02-22) — a work of the U.S. government in the
  **public domain**. Sourced from Wikimedia Commons
  (*File:SDO 20110222 1024 0171 (AIA).ogv*), cropped and scaled into a looping
  sprite-sheet. NASA SDO: https://sdo.gsfc.nasa.gov/.
- **Sirius A:** the bundled image (`godot/assets/stars/sirius.png`) is the
  **NASA/ESA Hubble** photograph of Sirius A and its white-dwarf companion Sirius B
  (WFPC2, 2005) — **public domain** (NASA Hubble / pre-2009 ESA Hubble material).
  Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester).
  Sourced from Wikimedia Commons (*File:Sirius A and B Hubble photo.jpg*). It is a
  real still shown with a procedural twinkle (scintillation), since the brightest
  star is an unresolved point with no surface footage.
- **Betelgeuse:** the bundled loop (`godot/assets/stars/betelgeuse.png`) cross-fades
  three **real ESO/VLT SPHERE** images of Betelgeuse's resolved surface during the
  2019–2020 "Great Dimming" (January 2019, December 2019, January 2020). **CC-BY
  4.0**, credit **ESO/M. Montargès et al.**; sourced from Wikimedia Commons
  (eso2109f / eso2109e / eso2109d) and cropped, brightened, and cross-faded into a
  loop. Betelgeuse is the only star besides the Sun whose disk we can resolve.

The bundled imagery is public-domain (Sun, Sirius) or CC-BY 4.0 (Betelgeuse —
attribution as above, modified by cropping/cross-fading). Operators should still
confirm the licensing status that applies to their own use before public display,
and may drop their own media into `godot/assets/stars/source/` to replace any of
these.

## Bragg Peak Hunter — "X-ray Detective" imagery

Real sample/structure images in `godot/assets/bragg/`, from Wikimedia Commons
(the diffraction patterns themselves are drawn procedurally, not photos):

- **Salt structure** (`nacl_structure.png`) — *File:Sodium chloride crystal.png* by
  H. Padleckas, **public domain**.
- **Salt crystals, sample** (`nacl_sample.jpg`) — *File:Salt Crystals macro.jpg* by
  Prosthetic Head, **CC BY-SA 4.0**, downscaled (otherwise unmodified).
- **DNA double helix** (`dna_structure.png`) — *File:DNA double helix 45.PNG* by
  Jerome Walker / Dennis Myts, **public domain**.
- **Insulin structure** (`insulin_structure.png`) — *File:Insulin hexamer 4INS.png*
  by Fvasconcellos, **public domain**, downscaled.
- **Insulin crystals, sample** (`insulin_sample.jpg`) — *File:Insulincrystals.jpg* by
  **NASA/Marshall**, **public domain** (insulin grown aboard the Space Shuttle).

All are public domain except the salt-crystal photo (CC BY-SA 4.0, credited above).
The DNA sample slot and all diffraction patterns are code-drawn (no external image).
Operators should confirm the licensing for their own use before public display.

## Atomic Builder — flame-test photos

Real flame-test photographs in `godot/assets/atomic/`, from Wikimedia Commons. All
**public domain** (released by their author, "Herge", at the German Wikipedia project):

- **Lithium flame** (`flame_li.png`) — *File:FlammenfärbungLi.png*, **public domain**.
- **Sodium flame** (`flame_na.png`) — *File:FlammenfärbungNa.png*, **public domain**.
- **Potassium flame** (`flame_k.png`) — *File:FlammenfärbungK.png*, **public domain**.
- **Calcium flame** (`flame_ca.png`) — *File:FlammenfärbungCa.png*, **public domain**.

Downscaled to ~320 px wide, otherwise unmodified. The emission-line strips, periodic
table, orbital boxes, and N-vs-Z stability plot are all code-drawn (no external image);
a missing flame photo falls back to a code-drawn colour swatch. Operators should confirm
the licensing for their own use before public display.


## Godot Engine

This game uses Godot Engine. License and third-party notices:
https://godotengine.org/license/