The most powerful solar storm in more than two decades struck Earth on Friday, triggering spectacular celestial light shows from Tasmania to Britain, but scientists say the event could bring possible disruptions to satellites and power grids.
Starlink, the satellite arm of Elon Musk's SpaceX, warned on Saturday of a "degraded service".
Starlink owns around 60 per cent of the roughly 7,500 satellites orbiting Earth and is a dominant player in satellite internet.
Musk said earlier in a post on X that Starlink satellites were under a lot of pressure due to the geomagnetic storm, but were holding up so far.
The first of several coronal mass ejections (CMEs) – expulsions of plasma and magnetic fields from the Sun – came just after 5pm UK time, according to the National Oceanic and Atmospheric Administration (NOAA)'s Space Weather Prediction Centre.
The sun has produced strong solar flares since Wednesday, resulting in at least seven outbursts of plasma.
It was later upgraded to an “extreme” geomagnetic storm and is now classified as a G5 event on a scale from G1 to G5, the first since the “Halloween Storms” in October 2003 caused blackouts in Sweden and damaged power infrastructure in South Africa.
More CMEs are expected to pummel the planet in the coming days.
Authorities notified satellite operators, airlines and energy providers to take precautionary steps for potential disruptions caused by changes to Earth's magnetic field.
Unlike solar flares, which travel at the speed of light and reach Earth in around eight minutes, CMEs travel at a relatively more sedate pace, with officials putting the current average at 800km per second.
The CMEs emanated from a massive sunspot cluster that is 17 times wider than our planet. The Sun is approaching the peak of an 11-year cycle that brings heightened activity.
The public were encouraged by the NOAA's Brent Gordon to try to capture the night sky with phone cameras even if they could not see auroras with their naked eyes.
“Just go out your back door and take a picture with the newer cell phones and you'd be amazed at what you see in that picture versus what you see with your eyes,” he said.
Carrington Event
Fluctuating magnetic fields associated with geomagnetic storms induce currents in long wires, including power lines, which can potentially lead to blackouts. Long pipelines can also become electrified, leading to engineering problems.
Officials said the public should have the normal backup plans in place for power cuts, such as having torches, batteries and radios at hand.
The most powerful geomagnetic storm in recorded history, known as the Carrington Event after British astronomer Richard Carrington, occurred in September 1859.
Excess currents on telegraph lines at that time caused electrical shocks to technicians and even set some telegraph equipment ablaze.
High radiation risks
NASA said the storm posed no serious threat to the seven astronauts aboard the International Space Station. The biggest concern is the increased radiation levels, and the crew could move to a better shielded part of the station if necessary, according to Rob Steenburgh, a scientist with NOAA’s Space Weather Prediction Center.
Extremely sensitive instruments will be turned off, if necessary, to avoid damage, Antti Pulkkinen, director of the space agency’s heliophysics science division told AP.
Increased radiation could threaten some of NASA’s science satellites.
