Chemtrail Detector
ChemTracker is a chemtrail detection app that combines live flight tracking with real-time atmospheric science. Using the Schmidt-Appleman criterion — the thermodynamic model behind contrail prediction — it identifies which aircraft are currently in conditions that favor visible trail formation, so you can compare what you see in the sky with what the data actually says.
The Sky Scanner
The most direct way to use ChemTracker as a detector is the sky scanner. Open it, point your phone at any aircraft in the sky — with or without a visible trail — and within two seconds you see:
- Flight identity: Airline, flight number, origin, destination, aircraft type and registration.
- Altitude and speed: Exact altitude in feet and metres, ground speed, vertical rate.
- Atmospheric conditions:Temperature and relative humidity at the aircraft's reported altitude, sourced from weather model data.
- Trail prediction: Whether the Schmidt-Appleman criterion is currently met at that altitude — with a probability score that accounts for atmospheric measurement uncertainty.
- Anomaly flag: If conditions do not support trail formation but you observe a persistent trail from this aircraft, the app flags it as an atmospheric anomaly worth noting.
The scanner uses your device's GPS, compass, and camera together. It does not use image recognition to identify aircraft — it uses your pointing direction and location to match visible aircraft with ADS-B flight data. This makes it fast, reliable, and independent of visual conditions. For a broader view of all aircraft in your area, see the chemtrail map.
The Science Behind the Detection
The Schmidt-Appleman criterion (SAC) is the foundation of ChemTracker's detection engine. Developed by thermodynamicists Erich Schmidt and Hermann Appleman, it defines the conditions under which jet engine exhaust will condense into visible ice crystals — a contrail.
The Critical Temperature G
The SAC calculates a critical temperature threshold G from three engine parameters: the overall propulsion efficiency (η), the specific humidity of the exhaust (EI_H₂O), and the lower heating value of the fuel. G varies by engine type and fuel, typically falling between −45°C and −35°C at standard cruising altitudes.
The Formation Condition
A contrail forms when the ambient temperature at the aircraft's altitude is below G AND the mixing trajectory of exhaust and ambient air crosses the water saturation curve. If either condition is not met — temperature too warm or air too dry — no visible trail forms.
Persistence vs. Dissipation
A trail that forms will persist only if the ambient air is supersaturated with respect to ice (relative humidity over ice > 100%). In subsaturated air, a trail may form briefly but evaporate within seconds to minutes. In supersaturated air, the ice crystals grow and the trail spreads, sometimes into cirrus-like cloud cover that persists for hours.
Monte Carlo Uncertainty
Atmospheric data has measurement uncertainty. A single temperature reading at 250 hPa has an error range. ChemTracker runs a Monte Carlo simulation — hundreds of calculations with small random variations in input parameters — to produce a probability distribution rather than a single binary answer. This is expressed as a percentage confidence in trail formation.
ChemTracker vs. Other Flight Apps
Standard flight tracking apps are built for aviation enthusiasts who want to follow routes. ChemTracker is built for people who want to understand atmospheric activity.
| Feature | Flight Radar Apps | ChemTracker |
|---|---|---|
| Live flight positions | ✓ | ✓ |
| Altitude and speed | ✓ | ✓ |
| Flight number and route | ✓ | ✓ |
| Atmospheric conditions at altitude | — | ✓ |
| Schmidt-Appleman trail prediction | — | ✓ |
| Trail probability score | — | ✓ |
| Sky scanner (point at plane) | — | ✓ |
| Anomaly detection | — | ✓ |
| Trail activity alerts | — | ✓ |
| Contrail forecast | — | ✓ |
Frequently Asked Questions
How does ChemTracker detect chemtrails?
ChemTracker combines real-time ADS-B flight data with atmospheric conditions (temperature, humidity, and pressure at each aircraft's exact altitude) and applies the Schmidt-Appleman criterion — the thermodynamic model used by atmospheric scientists to predict contrail formation. If an aircraft is flying through conditions where the criterion is met, it is flagged as a trail producer. A Monte Carlo simulation adds a probability band to account for measurement uncertainty.
What is the Schmidt-Appleman criterion?
The Schmidt-Appleman criterion (SAC) is a set of thermodynamic equations first described by Erich Schmidt in 1941 and refined by Hermann Appleman in 1953. It calculates a critical temperature threshold G based on the engine's fuel-to-air ratio, exhaust properties, and ambient atmospheric pressure. If the actual temperature at the aircraft's altitude is below G and relative humidity is sufficient, contrail formation is predicted. ChemTracker applies this calculation to every aircraft in real time.
Can ChemTracker detect trails that shouldn't be there?
ChemTracker shows you when an aircraft is outside the conditions where the Schmidt-Appleman criterion predicts trail formation, and yet a trail appears to be present. This is one of the most requested features: identifying anomalies between predicted and observed trail behaviour. The app gives you the data to make that assessment yourself.
Does the sky scanner work in all weather conditions?
The sky scanner uses your phone's camera and compass to overlay flight data on what you are pointing at. It works whenever your device has a GPS lock and camera access. Cloud cover does not affect the scanner — it shows you aircraft even when they are hidden by clouds, because it is using flight data rather than image recognition. Clear sky conditions obviously make visual confirmation easier.
How accurate is the trail detection?
Trail prediction accuracy is constrained primarily by the resolution of atmospheric data, which is updated hourly from weather model outputs. For most commercial flights at standard cruising altitudes, the Schmidt-Appleman prediction matches observed trail behaviour approximately 85–90% of the time in controlled comparisons. ChemTracker uses Monte Carlo simulation to express this uncertainty as a probability range rather than a binary prediction.
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