The colourful electrical phenomenon Aurora Australis may be visible in skies in southern Victoria and Tasmania tonight thanks to a powerful solar ejection from the sun’s surface.
“It’s very unusual to have this sort of thing happening during this time in the sun’s cycle, so that’s why everyone’s really excited about it,” says Melbourne University physicist Clare Kenyon.
The Bureau of Meteorology forecasts that solar eruptions – large clouds of plasma called coronal mass ejections – will collide with the Earth’s atmosphere to produce brightly coloured displays.
Kenyon explains that the sun’s magnetic field activity fluctuates in cycles of about 11 years, making this particular event a rare one: “We’re currently at the end of solar cycle 24. And it should be, all things considered, quite quiet.”
The spectacular colours produced in auroras are caused by the solar storm particles interacting with gas molecules in the Earth’s atmosphere, with oxygen emitting greenish to yellow lights and nitrogen producing dark red and blue lights.
“Sometimes we have a blending of the colours and you can see pink, purple and white lights. That’s what makes the aurora amazing,” said Bureau of Meteorology space weather scientist Dr Zahra Bouya in a recent press conference.
The human eye is less equipped to see the colour changes during an aurora, so it’s worth taking along a DSLR camera. Kenyon suggests taking a long exposure photo.
“You’ll actually see some beautiful colours,” says Bouya. “It’s horizon length, it’s not just one small little patch of sky.”
Best viewing times will be between 3am and 5am on Friday – try and find a place away from city lights and with an uninterrupted view of the horizon, such as a dark beach or headland.
The Bureau of Meteorology has forecast relatively clear weather over Victoria for Thursday night, with the best viewing conditions to the west of Melbourne along the coast. Partly cloudy conditions are currently forecast for Hobart.