Extract from ABC News
Most people travel to Antarctica or Tasmania to see aurora australis, but recently photographers and stargazers across southern Australia have spotted light shows from their home towns on the mainland.
Key points:
- Auroras have been spotted as far north as Dubbo in western NSW recently
- An astronomer says the rare sightings are because the solar cycle is nearing its peak
- There could be heightened aurora activity for another two years
Photos of the aurora have been shared across social media, from as far north as Dubbo, in western New South Wales.
Karlie Alinta Noon is an astronomer from the Australian National University's Research School of Astronomy and Astrophysics.
She said auroras occurred when solar winds travelled through the solar system and high-energy particles interacted with Earth's magnetic field, which follow Earth's magnetic field lines, leading them to Earth's poles.
With Earth's magnetic field pointed towards the poles, the aurora is typically spotted further south than mainland Australia.
The interaction between these particles and gases in the atmosphere generates a spectacular light show from above.
"That's why we typically see auroras happening at the very top and bottom of the Earth," Ms Noon said.
"That's where the winds and all those high-energy particles are more likely to be able to penetrate Earth's magnetic field."
In the northern hemisphere, the lights are called aurora borealis and in the southern hemisphere, they are called aurora australis.
Why are auroras so active?
Ms Noon said the Sun naturally went through a 22-year cycle.
As part of this, there was an 11-year period where it experienced a solar minimum and was not very active.
"The next 11 years is the solar maximum where we're seeing a lot of activity, there are a lot of solar flares, and a lot of really high energy wind coming from the Sun," she said.
Ms Noon said we were experiencing a "really special time" as the cycle neared its peak, something that only happened about every 20 years.
"We're just at the brink of the maximum. Even within that solar maximum, there is a point in time where it reaches its absolute maximum," she said.
"What we see at that point is a really large amount of sunspots and solar flares."
Spotting the aurora further north
With Earth's magnetic field weakest at the poles, the aurora is typically spotted further south than mainland Australia.
But Ms Noon said if solar flares and wind were very active, high-energy particles could penetrate more of the magnetic field.
"Even though the magnetic field is a lot thicker in places like Dubbo, if we have enough high-energy particles they can actually penetrate all of that magnetic field," she said.
Ms Noon said solar activity was higher than expected and it could stay that way for the next couple of years.
"We're seeing a lot more flares, a lot more winds coming to us a lot earlier than predicted," she said.
"By the end of 2025 that maximum, the peak, we'll be on the other side of that and the solar activity will start to decrease."
Spotting auroras
Emmily Meyers is a photographer from Lockhart, in southern NSW.
She said she had seen the aurora several times over the past 12 months.
"Out here we have to use cameras, either new phones or a digital camera will get it, but it's not something we can see with our naked eye," she said.
"Camera sensors are a lot more sensitive to light than our eyes are, they can see a range of colours."
Ms Noon said anyone who wanted to see an aurora should monitor the solar cycle, with groups like NASA offering great resources.
"If you see a peak in the number of sunspots or solar flares, it would be a great time to schedule in some night viewing," she said.
"Go somewhere high. The less atmosphere the light has to travel through, the more you'll be able to see."
Ms Meyers said photographers might need to search for a good location to get the best shot.
"For standard photos, you're better off wanting an absolutely clear horizon with no clouds and no light pollution from other towns," she said.
Links to Indigenous culture
Ms Noon, a Gamilaraay woman who is also an Indigenous research associate, said Aboriginal and Torres Strait Islander people had been observing the sky for thousands of years.
"[Auroras] have been associated with ancestors and activities happening up in the sky," Ms Noon said.
"They've been interpreted as things like warnings to warn elders that maybe something isn't quite right on country, forebearers of bad news."
Editor's note 1/03/2023: This article has been amended to reflect clarification from Ms Noon that it is more accurate to say particles follow Earth’s magnetic fields to the poles, causing auroras, rather than the field being weakest at the poles.
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