Physics checks and sources
What a record's checks compare, and where the numbers come from
Every Auriginal record lists which of the iPhone's sensors witnessed the capture and which physics checks agreed. Auriginal runs three physics checks. Each compares a signed reading with a published reference. A check can only add to a record. It never marks a capture as failed. Location is never shown publicly.
1. Magnetic field
The magnetic field strength the iPhone measured, compared with the strength Earth's field should have at that place and date, from the World Magnetic Model 2025. The model is computed on the iPhone and on our server, with no outside network calls.
Source: NOAA NCEI and British Geological Survey, World Magnetic Model 2025
2. Gravity
The motion sensor's reading while the phone was held still, compared with Earth's standard gravity (9.80665 m/s², exact by definition). The check is skipped if the phone was moving.
Source: NIST CODATA — standard acceleration of gravity (9.80665 m/s²)
3. Sun position
Only in bright daylight: the scene brightness the camera measured, compared with the sun's height in the sky at that time and place.
Source: NOAA Global Monitoring Laboratory, Solar Calculator (equations from Jean Meeus, Astronomical Algorithms)
Sensors that can witness a capture
A sensor witnessed a capture if it took a reading at that moment. A record lists only the sensors that did.
Camera · Motion (accelerometer and gyroscope) · Orientation · Compass (magnetic field) · Depth · Light (camera exposure) · Location · Air pressure · Sound (video) · Bluetooth · Wi-Fi · Cellular
Witnessing means a reading was recorded. It isn't a check of that reading. Location is recorded only to an area about 1 km across and is never shown publicly.
These are the only physics checks in this version. The record page shows which ones agreed for each capture.