ROOT / SOLAR FLARES // DECODED · reading GOES X-ray
// SOLAR WEATHER · THE SUN, DECODED · Solar Cycle 25 · declining phase

The Sun's fury,
in real time.

Solar flares are the most powerful explosions in the solar system — magnetic energy stored above sunspots, released in minutes, arriving at Earth in eight. This is the live instrument panel: what the Sun is doing right now, where it's hitting Earth, and every great flare ever recorded. Live data from NOAA SWPC and NASA. Primary sources, zero hype.

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Current X-ray flux class · GOES
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Planetary Kp index · geomagnetic
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Biggest flare · last 24 h
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Active sunspot regions today
// Live theater

The Sun, and where it hits Earth.

Left: the Sun and its active regions, the eruption scaled to the live X-ray flux. Right: a live globe — the sunlit hemisphere is where a flare's radiation lands, peaking at the sub-solar point.

◊ THE SUN · GOES XRS
LIVE
Current class · —flux —
◊ EARTH · FLARE IMPACT
REAL-TIME
Sub-solar point · —dayside = HF blackout zone
// Real-time impact map

Where the flare is hitting now.

Solar X-rays only reach the daylit half of Earth. The shaded lobe is the current radio-blackout footprint — brightest under the Sun, fading to the day/night line. Its intensity tracks the live flux.

◊ HF RADIO BLACKOUT · D-REGION ABSORPTION · —
● sub-solar point ▨ sunlit / affected ▨ night · no blackout
// Live telemetry

GOES X-ray flux,
last 24 hours.

One-minute soft X-ray irradiance (1–8 Å) straight from NOAA's GOES satellite. Each band is a flare class. When the line crosses into M or X, Earth's sunlit side takes a radio hit.

A/B quiet C common M radio blackout X severe source · NOAA SWPC GOES primary
// The scale

How flares are classified.

By peak soft-X-ray brightness, on a logarithmic ladder. Each letter is ten times the one before it.

A
10⁻⁸ W/m²
Background. The quiet Sun's baseline — no effect on Earth.
B
10⁻⁷ W/m²
Minor. Common even at solar minimum. Undetectable at the ground.
C
10⁻⁶ W/m²
Small. Several a day near solar maximum. Little practical effect.
M
10⁻⁵ W/m²
Medium. Brief HF radio blackouts near the poles and on the dayside.
X
10⁻⁴ W/m²+
Severe. Planet-wide dayside radio blackouts; the scale has no ceiling — X10, X28, beyond.
The number after the letter is linear: M5 = 5×10⁻⁵ W/m², X2 = 2×10⁻⁴. X keeps counting past 9 — the largest ever recorded, 4 November 2003, saturated the sensors and was estimated at X28, with independent methods putting it as high as X40–X45. Note: NOAA rescaled the GOES archive in 2020 (removing an old 0.7 factor), so modern flares read about 40% "larger" than identically-numbered flares before 2016 — cross-era comparisons carry that caveat.
// NOAA space-weather scales

Three storms,
three yardsticks.

One eruption drives three different hazards, each with its own 1–5 scale: radio blackouts (R), radiation storms (S), and geomagnetic storms (G).

R · Radio blackouts

driven by the flare's X-rays
R1M1 flare. Weak HF fade on the sunlit side.
R2M5. HF loss for tens of minutes, dayside.
R3X1. Wide-area HF blackout 1 hour.
R4X10. Most of the sunlit side out 1–2 hours.
R5X20. Complete dayside HF blackout for hours.

S · Radiation storms

driven by solar energetic particles
S110 pfu. Minor polar HF impact.
S210² pfu. Radiation risk to polar aircrew.
S310³ pfu. EVA hazard; satellite noise; panel wear.
S410⁴ pfu. Polar HF blackout; memory upsets.
S510⁵ pfu. Satellites crippled; serious crew dose.

G · Geomagnetic storms

driven by the CME, 1–3 days later
G1Kp 5. Aurora at high latitude; minor grid ripple.
G2Kp 6. Aurora to 55°; more satellite drag.
G3Kp 7. Aurora to 50°; voltage corrections.
G4Kp 8. Aurora to 45°; grid protection may trip.
G5Kp 9. Aurora to the tropics; grids can collapse.
// Effects on Earth

One eruption,
three waves.

A flare is not a single event that reaches Earth all at once. Light comes first, particles next, and the plasma cloud days later — each with different effects.

Wave 1 · radiation
The flare
arrives in 8 min · speed of light

X-rays and EUV slam the dayside ionosphere, ionizing the D and E layers. High-frequency radio is absorbed instead of reflected — the sudden ionospheric disturbance and HF blackout, plus prompt GPS/GNSS position errors. This is the R-scale, and it happens on the sunlit half of Earth only.

Wave 2 · particles
The SEPs
minutes to hours later

Solar energetic protons, guided along magnetic field lines, flood the polar caps — polar HF blackouts, satellite single-event upsets, solar-panel degradation, and a real radiation dose for astronauts and polar-route aircrews. This is the S-scale.

Wave 3 · plasma
The CME
1–3 days later

A coronal mass ejection — billions of tons of magnetized plasma — strikes the magnetosphere and drives the geomagnetic storm: brilliant auroras, ground-induced currents that stress power grids, and thermospheric heating that drags satellites down. This is the G-scale. Auroras and grid damage come from here, not the flare's light.

Radio & navigation

HF blackouts

Aviation, maritime, ham and emergency HF radio fade on the dayside. In Sept 2017 an X9.3 flare degraded the HF links used for Hurricane Irma and Maria relief in the Caribbean.

Low Earth orbit

Satellite drag

Heating puffs up the upper atmosphere, raising drag in LEO. In Feb 2022 a merely moderate storm dragged down 38 of 49 freshly launched Starlink satellites before they could raise orbit.

Power & agriculture

Grids & GPS

Ground-induced currents can trip transformers — Québec lost power for 9 hours in 1989. In the May 2024 Gannon storm, RTK-GPS outages hit farm tractors mid-planting, costing affected farms around $17,000 each.

// The record

Every great storm,
1859 → now.

The events that defined space-weather history — from the telegraph-frying Carrington Event to the worldwide auroras of 2024. Red marks a record-class flare; green marks the modern era.

// All-time records

The most powerful flares
ever recorded.

Ranked by peak X-ray class since satellite monitoring began in 1975. Search or sort. Classic operational scale (see the note under the classification ladder).

X28+

4 November 2003 · the largest on record

Active region 10486 unleashed a flare so intense it saturated GOES detectors at X17.4; NOAA extrapolated X28, and independent ionospheric methods estimated up to X40–X45. It erupted as the region rotated off the Sun's western limb, so the worst of the blast missed Earth. The same region drove the Halloween Storms days earlier.

# Date Peak class▾ Region Notes
Modern GOES-R flares (2017+) are on the true flux scale; pre-2016 values carry the historical 0.7 scaling. Sources: NOAA SWPC, Australian Space Weather Service, Hudson et al. 2023.
// Live feed

Flares in the last 7 days.

Pulled live from NOAA's GOES flare log. A green CME tag means the flare launched a coronal mass ejection — watch for a geomagnetic storm 1–3 days later.

reading NOAA flare log…
// Beyond the record books

The ones we only see in the trees.

Long before satellites, monster solar particle storms left spikes of carbon-14 in tree rings and beryllium-10 in ice. These "Miyake events" dwarf anything in the instrument era.

c. 12350 BC

The strongest known

The most intense solar particle event ever detected — roughly 18% stronger than AD 774, and on the order of 500× the strongest modern (2005) particle storm.

AD 774–775

The archetype

A carbon-14 spike about 20× normal variability — an estimated 10× or more the particle fluence of the Carrington Event. Now used as a global tree-ring dating anchor.

660 BC · AD 993 · 5259 BC · 7176 BC

The confirmed few

A handful of other extreme events are confirmed across tree rings and ice cores worldwide. A repeat today would threaten satellites, aviation dose and grids well beyond a Carrington scenario.

// Sources & live data

Where this comes from.

Live telemetry: NOAA Space Weather Prediction Center — GOES X-ray flux, flare log, planetary Kp index, and active-region summary (services.swpc.noaa.gov). Flare catalog and CME linkage: NASA DONKI (api.nasa.gov). Imagery reference: NASA Solar Dynamics Observatory (sdo.gsfc.nasa.gov). Historical record: NOAA SWPC, NOAA NCEI, the Australian Space Weather Service flare list, Hudson et al. 2023 (GOES saturation reanalysis), and the peer-reviewed literature on the Carrington, 1921, 1989, 2003, 2012, 2022 and 2024 events. Miyake-event data from cosmogenic-isotope studies (Miyake 2012 onward). The sub-solar point and day/night terminator are computed live from UTC — accurate to a fraction of a degree.

NOAA GOES X-ray flux ↗ NOAA SWPC ↗ NASA SDO ↗