Understanding space weather

Activity on the Sun and changes in the near-Earth space environment. Solar flares, energetic particles and geomagnetic storms are different phenomena, not interchangeable names for the same event.

No. A flare is not the same as an Earth-directed mass ejection. Aurora also depends on the arriving solar wind, magnetic-field direction, location, darkness and weather.

NOAA uses G for geomagnetic storms, S for solar radiation storms and R for radio blackouts. Each scale runs from 1 to 5; a zero means below the scale, not missing data.

Image colours depend on the instrument and wavelength. Compare images from the same channel; a dark coronal hole is not a hole in the Sun.

Sunspot count alone is not enough. Region size and magnetic complexity help assess flare potential, but neither predicts a storm at Earth.

Flare strength runs from A through B, C and M to X. At the same number, each letter class is ten times stronger than the previous one.

The peak marks the strongest X-ray emission, not the flare’s duration or a CME arrival. All table times use UTC.

It can suggest a region to watch as the Sun rotates. It cannot establish the time, strength or Earthward direction of a future eruption.

Upstream spacecraft measure the wind before it arrives. Travel time depends on speed; the Earth reference is an estimate, not a fixed countdown.

Bt is the total magnetic-field strength. A sustained negative Bz points south and can help solar-wind energy enter Earth’s magnetic environment; it does not guarantee aurora.

Check direction and the latest model, not just eruption speed. A halo appearance alone is not confirmation of an Earth impact.

Kp runs from 0 to 9. The geomagnetic storm scale starts at Kp 5. It is a global indicator, not the chance of seeing aurora in a particular city.

Kp 5 reaches the G1 storm threshold, but visibility depends on latitude, darkness and cloud. Check a local forecast before planning a trip.

Energetic particles matter for spacecraft and some polar aviation and radio operations. This is not a local radiation-dose or health-risk measurement.

Read the issue time and valid period first. Use the three-day forecast for near-term planning; the 27-day outlook is a broad trend, not an hourly forecast.

Watch means increased possibility; Warning means conditions are expected; Alert means an observed threshold was reached. Check validity, extensions and cancellations.

It is the chance of that flare class during the stated period, not its duration. C, M and X probabilities need not add up to 100%.

It describes a more active phase, not a date for the next storm. The 13-month smoothed curve shows the broad trend, not daily changes.

Each source has limited coverage and may have gaps. Check the available dates and chosen measurement; no record is not a measured zero.

Align UTC times, units and sampling periods first. A flare peak, a three-hour Kp value and a monthly sunspot count describe different things.