EncyclopediaTERRA combines live observations, curated event feeds, forecasts and orbital data. This encyclopedia explains what each mode means, what an event represents and what it does not mean.
What is happening on or near the planet: earthquakes, fires, floods, cyclones, volcanoes and official weather warnings.
What is happening between the Sun and Earth: aurora, geomagnetic activity, solar flares, CMEs, solar radiation and radio effects.
Where selected satellites and stations are now, how their orbits propagate and when they may pass above your location.
Observed earthquakes from the USGS real-time feeds. TERRA shows magnitude, depth, time and location when supplied by the source. A marker is an observed event, not an earthquake forecast.
NASA EONET events curated as active wildfires. EONET links event metadata to related Earth-observation information; the marker represents the reported event location.
Satellite-derived thermal anomalies detected by instruments such as VIIRS and MODIS. A detection can indicate fire or another hot surface and is not a fire perimeter; TERRA may cluster detections for readability.
Open severe-storm events curated by NASA EONET. The event can represent a reported storm system and its latest available point, not a complete storm footprint.
Open volcanic events curated by NASA EONET. The marker identifies the reported event position; it does not imply that the whole surrounding area is hazardous.
Flood events and alert levels supplied by the Global Disaster Alert and Coordination System. A GDACS alert is an information and coordination signal, not a local damage assessment.
Tropical cyclone events and alert levels from GDACS. The event describes the tracked system; it is not a guarantee of local wind, rainfall or impact at a specific point.
Some earthquakes are flagged by USGS for tsunami review. TERRA labels this explicitly as a check: it is not an official tsunami warning.
Regional or point-based official weather warnings. A warning describes a hazard or expected condition within its published scope; a region name alone does not prove that a specific Watch Area is affected.
A forecast of auroral activity around the polar regions. TERRA renders the field on Earth to show where auroral activity may be stronger; local visibility still depends on darkness, clouds and latitude.
Geomagnetic disturbance caused by changes in the near-Earth magnetic environment. NOAA uses G1–G5, with higher levels indicating stronger disturbance and potentially greater effects on satellites, navigation, radio and power systems.
Elevated energetic particle levels, especially protons. The S scale runs from S1 to S5 and describes possible effects on spacecraft, polar aviation, communications and navigation.
Solar-flare-driven disturbances that can degrade or black out high-frequency radio on the sunlit side of Earth. R1–R5 describes increasing severity.
Rapid bursts of electromagnetic energy from the Sun. GOES X-ray measurements classify flares from A through X; stronger classes can be associated with stronger radio-blackout effects.
Large expulsions of magnetized plasma from the Sun. A CME may contribute to a later geomagnetic storm if it reaches Earth, but an observed CME is not itself a guarantee of an Earth impact.
The continuous flow of charged particles from the Sun. TERRA uses measured solar-wind speed, density and magnetic-field context to illustrate the Sun–Earth environment.
Measured energetic proton flux near Earth. TERRA uses it to describe the radiation environment; the visual rings are indicative and are not a measured boundary or radiation dose map.
Kp is a 0–9 index of global geomagnetic activity. TERRA also shows NOAA forecast values where available; forecasts describe possible conditions, not guaranteed outcomes.
Selected crewed or major space stations such as the ISS and CSS. Their positions are propagated from current orbital elements.
Selected meteorological satellites such as NOAA and Metop spacecraft. They are shown as orbital objects, not as weather events themselves.
Selected GNSS/navigation objects such as NAVSTAR/GPS spacecraft. TERRA shows their propagated orbital position; it does not represent live receiver accuracy or service availability.
TERRA propagates current orbital elements to estimate the object position at the current time. Visual altitude is compressed for readability and is not to scale.
The point where the propagated satellite position projects onto Earth. It is a calculated sub-satellite point, not the location of a physical signal or footprint.
For a selected object, TERRA can estimate upcoming passes above your location. A pass means the satellite rises above the chosen elevation threshold; daylight, clouds and visibility are not assessed.
Weather information in TERRA is separate from disaster events. A forecast describes modelled atmospheric conditions; an official warning communicates a hazard within a published scope.
Forecast or observed precipitation expressed as an amount over a time period. Rain totals and rain rate are not the same measurement.
Wind speed and direction describe the movement of air at a modelled or observed level. Gusts are short-lived peaks and can be higher than sustained wind.
Near-surface air temperature from the weather model or observation source. Local terrain and elevation can affect how closely a model point matches conditions on the ground.
Atmospheric pressure, commonly expressed in hPa. Pressure patterns help describe weather systems but do not by themselves define local danger.
A forecast is a model estimate. It can change as new observations arrive, especially for precipitation, convection and local wind.
An observed event has already been reported by its source. A forecast describes a possible future state. TERRA keeps those concepts separate.
A point can represent an event location, a satellite detection, a model point or a calculated position. It does not automatically describe the full affected area.
Solar flares, CMEs and geomagnetic conditions are shown through Sun–Earth or geospace visualizations when a ground coordinate would be misleading.
Every event detail identifies its source. For operational decisions, open the original source and follow its current guidance.
Earth shows observed or officially reported events such as earthquakes, fires, floods, cyclones, volcanoes and weather warnings.
Space shows solar and geospace conditions such as aurora forecasts, geomagnetic storms, solar flares, CMEs, radiation and radio effects.
Orbit shows selected satellites and stations propagated from current orbital elements, plus estimated passes over your location.
No. Observed events are reports from their sources. Forecasts describe possible future conditions and should not be read as guaranteed outcomes.
TERRA is an information and monitoring interface. It does not replace official emergency warnings, aviation/maritime notices, local authorities or independent verification.
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