Aurora australis: southern lights to be visible across large parts of Australia amid severe solar storm

Skywatchers may be treated to a celestial delight on Wednesday evening, with a severe solar storm making it possible to view the southern lights across large parts of Australia – possibly including Sydney and Perth. An intense geomagnetic storm, caused by several powerful bursts of energy from the sun, has led the Bureau of Meteorology’s space weather forecasting centre to issue an aurora alert for “mid to southern parts of Australia”. Displays of the northern lights, also known as aurora borealis, were visible in the northern hemisphere overnight on Tuesday. Where might their southern counterpart, the aurora australis, be visible? What impacts might the severe solar storm have? Here’s what to expect. Related: Aurora australis: southern lights dazzle across New Zealand and Australia’s east coast – in pictures Where and what time is best to watch the aurora australis? “Given the strength of this storm, there’s a chance people farther north than typically expected in the southern hemisphere might be able to see it,” astronomer Dr Laura Driessen, from the Sydney Institute for Astronomy said, adding it could be visible to people in Sydney and Perth. “Tasmania and New Zealand should get a decent view,” she said. Wednesday night was “the best chance for people to go outside and try catch a glimpse of the aurora,” Dr Sara Webb, an astrophysicist at Swinburne University, said. “It looks like it’s going to be very high up the southern coast of Australia, so visible from parts of Victoria and New South Wales.” When it comes to aurora viewing, experts recommend heading somewhere dark, away from city lights, looking to the south, and allowing your eyes to acclimatise to the darkness first. “You might just see a hint of it with your naked eye, you might see something a little bit fuzzy, maybe a little bit red. That’s when it’s time to take out your camera and take a long exposure – you can do this on your mobile phone,” Webb said. “Set your camera to take, say, a 10-second photo … you’ll often find that when you look back at the photo over those 10 seconds, your phone has collected more light than your eyes can process.” What causes the aurora australis? According to the BoM on Wednesday, “G4 geomagnetic storm conditions are currently being observed.” The maximum on the geomagnetic storm scale is a G5. “It is quite an intense geomagnetic storm, one of the largest that we’ve seen in recent years,” Webb said . The sun has an activity cycle of about 11 years, which peaked last October. Around that solar maximum, “we get more sunspots, which are areas where there’s magnetic activity,” Webb said. “We also see things like coronal mass ejections … we get some of the magnetic field lines from the sun interacting with each other, essentially breaking, and releasing energy and plasma towards us.” Two “massive” coronal mass ejections have been observed since 9 November, which were expected to hit Earth on Wednesday afternoon, Webb said. These bursts of high-energy plasma disturb the Earth’s magnetic field, known as the magnetosphere. Auroras, or aurorae, result from that disturbance. “All of this in combination adds energy to some particles in our atmosphere,” Driessen said. “A lot of the colours we see are from oxygen and neon getting excited – as those particles calm back down again they emit these beautiful coloured lights.”   Will communications be disrupted in the solar storm? Experts say major impacts are rare. However, severe solar storms can impact radio infrastructure and satellites. The highly charged particles from these storms can disrupt GPS and observation satellites, Webb said. “What it might mean is that the satellite companies need to put their satellites into sleep mode – essentially, they shut them down so that there’s less risk of damage.” In 2022, a solar storm caused dozens of Starlink satellites to burn up in Earth’s atmosphere. “But really it’s quite rare, and a lot of satellites are built to withstand a certain level of these type of events,” Webb said. In 2003, intense geomagnetic storms resulted in a blackout in Sweden, disrupted flights in the northern hemisphere and affected over half of all Earth-orbiting spacecraft. “That’s something that we need to keep an eye out [for], but there’s … no major warnings [of] that happening,” Webb said.