Aurora encore: Another spectacular southern light show

The auroras of 11-12 May, 2024, were a global event, with millions of people seeing spectacular northern and southern lights.

While auroras are common in polar regions, on 11-12 May they became visible over a large portion of the globe, including southern Australia. Auroras were even visible from cities and suburbs, including my suburban street.

However, the best views were from dark sites and away from suburban light pollution.

On the evening of Saturday, 11 May, I went to Cape Schanck, an hour’s drive from Melbourne, where hundreds (perhaps thousands) of people watched the spectacular auroras. It was a festival of astronomy. We were wowed by beams of green and red light slowly moving across the sky, sometimes towering 60 degrees above the southern horizon.

While millions saw the spectacular auroras during 11-12 May, others weren’t so lucky. Many Melburnians were disappointed there wasn’t an encore display on the evening of Sunday, 12 May. But the good news is there will be more opportunities to see auroras during 2024.

Auroras are the result of disturbances on the Sun – coronal mass ejections – that send electrons travelling at vast speeds into space. When these electrons encounter the Earth’s magnetic field, they’re guided towards the Earth’s magnetic poles and produce auroras as they slam into the tenuous atmosphere more than 90 kilometres above the Earth’s surface.

If there’s a particularly violent coronal mass ejection (or ejections) aimed at Earth, then we can get auroras that are bigger, brighter and extend further than normal. This happened on 11-12 May, with an auroral display that may have been one of the best for decades.

So, when can we get to see auroras again?

Our Sun has an 11-year cycle of activity, and the cycle is at solar maximum during 2024, resulting in peaks in sunspots, solar flares, coronal mass ejections and auroras.

The current solar maximum is the most active for a few decades, which has been great for aurora spotting. While we may not get a display that matches 11-12 May, there will almost certainly be some good displays visible from southern Australia during 2024.

Auroras are fickle and not easy to predict, so don’t expect a simple prediction with a precise time and date. Instead, space weather websites, including those of the Australian BoM and American NOAA, will highlight stormy space weather conditions. That’s a sign auroras may be imminent.

NOAA also provides a 30-minute aurora forecast, which shows the regions of the world where auroras are probably visible right now. If that forecast is far from where you are, then it probably isn’t worth looking at. But if auroras are likely near your part of the world, then it’s worth taking a peek.

For me, the combination of smartphones and social media are two of the best and most accessible tools for aurora-spotting.

Smartphone cameras are now more sensitive than the human eye and can take great photos of auroras. And there’s social media groups for aurora-spotting, including groups that only allow posts of photos of auroras visible right now.

If I see a post of a good aurora happening right now, then I’ll go take a look. I particularly keep an eye on aurora sites if I’m in the countryside on clear moonless nights, when the best views are possible.

This happened the morning of Saturday, 20 April, when I was visiting Porepunkah and was struggling to sleep. I saw some posts of Victorian aurora photos, threw some clothes on, went outside, and was very much rewarded by views of auroras with red beams of light.

So get ready for more auroras, and perhaps as soon as early June. The Sun’s rotation is moving the sunspot group responsible for May’s display back into view, and it may still be in an angry mood. If it gets fired up at just the right time, we may get a beautiful auroral encore.