Australians should have a second chance to see the aurora australis on Sunday night, experts say, after a Saturday southern lights display so spectacular it left at least one astronomer in tears.
Social media users posted pictures of brightly coloured skies in Victoria, Tasmania, South Australia, and around the world.
Much of New South Wales missed out on the spectacle due to heavy cloud and rain.
A Monash University associate professor in astronomy, Michael Brown, described Saturday’s show – bigger than anything seen in Australia in decades– as “bloody awesome”.
“It was absolutely spectacular last night,” he said. “An ‘oh, wow’ moment.”
“I was looking at reactions of astronomers in the world and there was one – well-known in the field – who was brought to tears by it.”
Brown watched the display from his home in Melbourne, then drove more than an hour to Cape Schanck on the Mornington Peninsula for a better view.
He said hundreds of other stargazers were there – many grabbing great photos on their smartphones.
The Bureau of Meteorology has warned that the storm that creates the beautiful auroras could threaten infrastructure and essential services, including power supply.
The geomagnetic storm that created the “amazing light show” was the strongest in more than 20 years, the BoM said.
The BoM space weather forecasting centre manager, Kate Brand, said it was unusual for displays to be seen as far north as Mackay in Queensland.
“There is a chance of seeing auras, perhaps not as far north as last night, but we are expecting that they may be visible in the southern parts of Australia,” she said.
Brown agreed, saying he expected another display on Sunday night, as well as the chance for a repeat on Monday.
“There’s a very good chance that there’ll be a good aurora – probably not as spectacular as last night,” he said.
“But auroras can be really fickle. Sometimes they can disappoint and sometimes they can surprise you in a really good way, as they did last night.”
He recommended that people look outside if they were somewhere without much cloud cover or light pollution.
“At worst, you don’t see anything and at best you might see an amazing experience that you’ll remember for the rest of your life,” he said.
A BoM senior meteorologist, Christie Johnson, said cloud cover could clear along parts of the NSW coast. “There is some potential depending on exactly how the system moves,” she said.
“The northern coastal area could be some breaks in the cloud and it might be OK for viewing, inland parts should be OK. Sydney is right on the edge of where we might see [it].”
The BoM warned that wet weather would persist for much of eastern NSW for the next few days, with flash flooding in some areas due to heavy rainfall and flood warnings issued for parts of the Hawkesbury and Nepean.
Sydney’s Warragamba Dam was spilling over after reaching capacity on Sunday morning. WaterNSW said the dam began spilling at 7.30am.
On Wednesday and Thursday there were four coronal mass ejections from the sun, meaning highly charged plasma erupted and streamed into space.
When those charged particles, known as the solar wind, hit the Earth’s magnetic field, they create the stunning visual displays known as auroras.
“The last time a G5 geomagnetic storm was observed was in 2003,” the BoM said. “The warning issued for this event informs government and critical infrastructure operators so they can take action to mitigate potential impacts on infrastructure and essential services.”
It added: “When G5 geomagnetic conditions occur, bright auroras will be visible at unusually low latitudes, including dark-sky locations near Sydney and Perth.”
The bigger the storm, the closer to the equator the lights appear.
The northern lights – aurora borealis – were visible across large parts of Europe, including in the UK, on Saturday morning.