Northern lights: what causes them and where will I be able to see them?

With reports of spectacular views of the northern lights on Thursday night, including sightings as far south as Kent in the UK, we take a look at what causes the phenomenon and how to catch a glimpse.

What are the northern lights?

The northern lights, or aurora borealis, appear as bright, dynamic curtains of colour in the night sky of the northern hemisphere.

In the southern hemisphere the same phenomenon is known as aurora australis or the southern lights.

These beautiful displays arise from activity on the sun. During events known as coronal mass ejections (CMEs), the sun spews out plasma – a super-hot gas made up of charged particles. When these particles head towards Earth, they can interact with the planet’s magnetic field, resulting in a geomagnetic storm.

Some of these particles are funnelled towards Earth’s magnetic poles, passing energy to atoms and molecules in the atmosphere such as oxygen and nitrogen. These gases then emit energy in the form of light.

The phenomenon typically occurs at high latitudes – think Canada, Scandinavia and near the south pole – but bigger CMEs mean the aurora can be seen further away from the poles.

Where and when can I see them?

Many people have already reported spectacular views on Thursday, but there is a chance the light show will be visible again on Friday, at least for some.

“The chances of aurora remain initially, though gradually easing through 11 Oct, becoming increasingly confined to far northern geomagnetic latitudes by 13 Oct,” the UK Met Office has said.

The service has reported that cloudier skies may reduce the likelihood of a sighting in the UK on Friday night, and that the best chance is in Scotland.

In the southern hemisphere, the Met Office said possible sightings of the aurora in Tasmania and New Zealand would reduce on Friday, and again the spectacle will be increasingly confined to high latitudes by 13 October.

Data from the Space Weather Prediction Center from the National Oceanic and Atmospheric Administration suggests the northern lights may be visible on Friday across large parts of North America, including Canada and the northern parts of the US states of Minnesota, North Dakota, Washington and Montana.

What’s the best way to see or photograph them?

“If the aurora is predicted to be visible over your local area, the best way to view them is to get away from any light pollution or other bright light sources,” said Jake Foster, an astronomer at the Royal Observatory Greenwich.

“To the naked eye, the aurora is unlikely to look very colourful, so taking photographs of the sky with a long exposure or night mode will be the best way to know if the aurora truly is happening above your head,” he said, noting that the longer the exposure time the more light the camera can acquire and the brighter the image will be.

If you are taking a picture, don’t forget to keep your camera steady – a tripod can help – and turn off the flash.

“Activity can noticeably increase and decrease over the course of just minutes, so a bit of patience may be rewarded,” Foster said.

Why have there been so many chances to see the northern lights this year?

The lights have been spotted in numerous places and further south than usual this year. This is because the sun is thought to be at the peak of its 11-year cycle of activity, meaning more CMEs are occurring and that those hoping to spot the aurora are in luck.