A peak in the solar cycle means we're getting spectacular aurora australis sightings — for now

Australia Broadcast Center

2 days ago

We've been treated to some stunning aurora australis light displays over the past few days, but don't expect the glow to last forever.
The Sun's 11-year cycle means we're currently in the midst of an explosion of aurora activity.
But that'll simmer down soon.
It's a phenomenon when the sky in the Southern Hemisphere is lit up by glowing whirls of colour.
You'll also hear it referred to as the southern lights.
"Australis" comes from the Latin word for "southern".
In the Northern Hemisphere, it's called the aurora borealis, or the northern lights.
Geomagnetic storms.
It's triggered by something called coronal mass ejections.
"A coronal mass ejection is the literal ejection of material from the Sun out into space," Australian Space Weather Forecasting Centre (ASWFC) forecaster Andrew Jackling says.
This sends charged particles from the Sun towards Earth, causing geomagnetic storms that can disrupt Earth's magnetic field.
"Kind of like in a normal thunderstorm, your shutters on your house would get a bit rattled by the wind and the rain," he said.
In a geomagnetic storm, the disruption can cause atoms of oxygen and nitrogen in the atmosphere to emit bright, colourful light.
"There was a large solar storm on the 31st of May," Australian National University astrophysicist Brad Tucker says.
"The storm was large enough to trigger a G4 storm on Earth.
"The scale is 1-5, like cyclones, with G5 the largest."
Here are some of the latest photos, posted to the ABC's Weather Obsessed Facebook group:
While auroras are usually limited to the southernmost parts of the country, there were sightings as far north as Tamworth in New South Wales.
And a big part of this is because of where we are in the solar cycle, which goes for roughly 11 years.
"The current solar cycle began in 2019, since which time solar activity has generally increased as the Sun progresses toward solar maximum, which officially began in October 2024," Mr Jackling says.
And that means spectacular auroras.
"During solar maxima, which we are at, the Sun produces more storms, and more extreme storms," Dr Tucker says.
"The activity is stronger so it is producing more of these."
But it's not just the individual storm from the past few days.
We've had some fairly spectacular aurora displays over the past year — check out the ABC's collection of photos from January, October, September and last July.
However, the most notable aurora displays happened in May 2024, when a G5 storm hit Earth.
It was the biggest geomagnetic storm we'd seen in 20 years, NASA says.
While it didn't cause any catastrophic damages, the event was so big it was given a name — Gannon storm — and was the subject of a big NASA study.
The solar maximum may continue for another year or two, Mr Jackling says.
"By 2027, solar activity is likely to have reduced from present levels, making geomagnetic storms and subsequent auroral displays less likely to occur," he says.
However, it's hard to tell exactly how long the aurora boom will last.
"Every 11-year period of maximum activity varies in strength," Dr Tucker says.
"Just like summers vary in how hot they are, or how wet/cold winters are, same, with the Sun, so some periods are better and others are less.
"This has been a good period."
No, they could still happen.
"Significant space weather can occur at other times in the cycle too," Mr Jackling says.
However, aurora australis activity during this time might not be visible as far north as we've been enjoying lately.
So aurora chasers may have to travel much further south.
"There is still an often low level of activity in the quiet years that you can get, but you need to be very near the south or north pole, which is why people make trips to the Arctic circle to see them," Dr Tucker says.
Also, it's important to remember that the solar cycle means we'll come back around to another solar maximum — we'll just have to wait about a decade.
Yep.
"The northern and southern lights are affected equally so they will reduce as well," Dr Tucker says.
However, people in the Northern Hemisphere have a better chance of seeing an aurora.
"It is generally easier to see the northern lights than the southern lights due to the geographic distribution of land in the northern hemisphere, where there are more populated areas closer to the northern polar region," Mr Jackling says.
"This is true at all times of the solar cycle."
The ASWFC, which is part of the Bureau of Meteorology, sends out geomagnetic storm alerts via email.
If you sign up to the ASWFC alerts via this online portal, you'll get an email when there's an alert.