# Earth and Moon texture credits

Retrieved and verified on 2026-10-23. These are NASA satellite-derived composites, not generated geography or live observations. All three maps are global 2:1 equirectangular images with north at the top. No crop, geographic rotation or flip was applied.

| Local file | Actual size | Source and processing |
|---|---:|---|
| `earth-day-8k.jpg` | 8192 × 4096 | NASA Blue Marble: Next Generation, June 2004, with shaded topography. Original 21600 × 10800 JPEG downsampled using macOS `sips`, JPEG quality 90. |
| `earth-night-2k.jpg` | 2048 × 1024 | NASA Black Marble 2016 color composite. Original 3600 × 1800 JPEG downsampled using `sips`, JPEG quality 92. |
| `earth-clouds-2k.jpg` | 2048 × 1024 | NASA Blue Marble cloud composite, published in 2002. Original JPEG preserved byte-for-byte. Black is clear sky; white is cloud. Use grayscale brightness as opacity; the JPEG itself has no alpha channel. |

## Day

Credit: NASA Earth Observatory / NASA Goddard Space Flight Center; Reto Stöckli.

- [NASA Blue Marble: Next Generation — base map with topography](https://science.nasa.gov/earth/earth-observatory/blue-marble-next-generation/base-topography/)
- [Original June 2004 global JPEG](https://assets.science.nasa.gov/content/dam/science/esd/eo/images/bmng/bmng-topography/june/world.topo.200406.3x21600x10800.jpg)

## Night

Credit: NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA GSFC. The color source includes a dark-blue land background as well as city lights; it is not a pure light-only radiance map.

- [NASA Earth at Night / Black Marble maps](https://science.nasa.gov/earth/earth-observatory/earth-at-night/maps/)
- [Original 2016 global color JPEG](https://assets.science.nasa.gov/content/dam/science/esd/eo/images/imagerecords/144000/144898/BlackMarble_2016_01deg.jpg)

## Clouds

Credit: NASA Goddard Space Flight Center; Reto Stöckli, with enhancements by Robert Simmon. The historical cloud image combines visible-light observations and thermal-infrared polar observations; it does not represent current weather.

- [NASA Visible Earth — Blue Marble: Clouds](https://visibleearth.nasa.gov/images/57747/blue-marble-clouds/77558l) (legacy catalog address may redirect after NASA's site migration)
- [Original cloud JPEG on NASA's image server](https://eoimages.gsfc.nasa.gov/images/imagerecords/57000/57747/cloud_combined_2048.jpg)

NASA imagery acknowledgment does not imply NASA endorsement of this game. See [NASA images and media guidance](https://www.nasa.gov/nasa-brand-center/images-and-media/).

Source files, checksums and verification metadata are retained outside the deployed site in `qa/planet-sources/earth-sources.json`.

## Moon

Credit: NASA Scientific Visualization Studio / Ernie Wright; LRO / LROC and LOLA instrument teams. [NASA CGI Moon Kit](https://svs.gsfc.nasa.gov/4720/). These are the 2019 rendering products, not live observations or a scientific measurement layer.

- `moon-color-8k.jpg`: 8192 × 4096 RGB, converted with macOS `sips` to JPEG quality 94 from [original 8K LROC TIFF](https://svs.gsfc.nasa.gov/vis/a000000/a004700/a004720/lroc_color_poles_8k.tif). No geographic crop or generated terrain.
- `moon-height-1k.jpg`: original 1024 × 512 [LOLA height map](https://svs.gsfc.nasa.gov/vis/a000000/a004700/a004720/ldem_3_8bit.jpg), retained byte-for-byte and used for subtle bump shading. This lower-resolution height layer complements, and does not replace, the 8K surface-color map.

The scene uses illustrative positions, scale, sunlight and slow cloud motion for gameplay. It is not an astronomical ephemeris or current weather simulation.