Huge solar prominence erupts in northwest away from Earth

A massive solar prominence erupted from the northwest limb of the sun on September 11, 2026, launching an expanding cloud of plasma from an active region located on the far side of the star. Instruments aboard the GOES-19 satellite, the Solar and Heliospheric Observatory LASCO C2 and C3 coronagraphs, and the Solar Dynamics Observatory recorded the blast as plasma surged outward into space without presenting any direct trajectory toward Earth.

Spacecraft track eruptions on the far side

The coronal mass ejection originated from a sunspot cluster that recently rotated beyond the northwestern edge of the solar disk. Because the underlying blast took place on the far side of the solar body, the expelled solar material travels away into interplanetary space and will not strike the geomagnetic field. Observers previously tracked two synchronized prominences erupting from opposite corners of the solar horizon on September 10 before this larger eruption occurred.

The plasma will miss Earth.

On the same topic: Sun enters a period of calm and does not affect Earth’s magnetic field

Flare frequency drops while active groups shift west

Solar flare production declined to nine total events during the twenty-four hours leading into September 11, 2026, marking a shift toward very low activity levels. That daily total included eight weak B-class flares and only one common C-class flare across the visible disk.

The strongest flare of the observation window reached magnitude C1.6 from sunspot group AR4530 at 17:12 UTC on September 10. AR4530 generated four flares during the period, leading all regions on the solar disk in eruptive output. Sunspot group AR4521 followed with three flares as it approached the northwestern limb.

Configuration of numbered solar regions

Seven numbered sunspot groups remain visible on the Earth-facing side of the sun, with all regions positioned in the western hemisphere due to solar rotation.

• AR4521 maintains an alpha magnetic classification and approaches the northwest horizon while ejecting faint flares and plasma.
• AR4525 exhibits a beta magnetic configuration and continued its physical growth across the disk.
• AR4530 shows a beta magnetic layout and generated the only C-class flare of the period.
• AR4524, AR4527, and AR4529 retain simple alpha structures with stable magnetic boundaries and no flare production.

The eastern hemisphere of the sun remains devoid of numbered sunspots because no fresh magnetic groups emerged from the eastern edge. Most visible active regions have retained simple magnetic profiles that reduce the likelihood of major eruptions.

Read also: Northern lights: moderate-class solar storm puts Earth on alert

Interplanetary magnetic conditions and plasma streams

Two filament eruptions occurred in the southwest quadrant prior to the northwest prominence, with the first taking place at 19:00 UTC on September 9 and the second at 03:15 UTC on September 10. Computer modeling indicates that both events generated slow-moving coronal mass ejections that could deliver a weak impact on late September 14 or early September 15. The interplanetary magnetic field total strength showed weak values while the Bz component fluctuated between northern and southern orientations.

Earth recorded planetary Kp index values ranging between 1 and 3 over the past day.

The geomagnetic environment fluctuated between quiet and unsettled levels as high-speed solar wind from an existing coronal hole waned. Peak southward alignments of the Bz magnetic field sparked isolated auroral displays near the Arctic Circle without triggering wider geomagnetic disturbances.

Forecast for geomagnetic activity and previous impacts

Space weather forecasts project solar activity to hold at very low levels through September 12, with an estimated 10 percent probability for M-class flares and a 1 percent chance for an X-class flare. The geomagnetic field should remain quiet to unsettled through September 13 under the influence of residual solar wind streams. Forecasters canceled an earlier G1 geomagnetic storm watch after anticipated plasma clouds from prior eruptions bypassed Earth or proved too weak to perturb planetary field lines.

Understand the case: Coronal mass ejection from the Sun approaches Earth and may generate auroras

The earlier sequence began when sunspot group AR4524 discharged four coronal mass ejections between September 5 and September 6, prompting a G1 geomagnetic storm at 07:30 UTC on September 8 when Kp values reached 5. A second pulse arrived ten hours later on September 8, driving Kp values back to level 5 at 17:44 UTC as auroras expanded across northern skies.

That earlier storm sequence followed a period of elevated flaring that produced 15 events on September 8, including nine C-class flares and six B-class flares. Sunspot group AR4528 fired the strongest flare of that phase, a C3.4 eruption at 23:39 UTC on September 8. Earlier on September 5, a decayed region designated AR4520 produced an M1.0 flare near the west limb that launched a fast halo CME and sparked an S1 proton event.

Sunspot region AR4528 produced a C1.0 flare at 19:35 UTC on September 7.