Good news for anyone wanting to see the northern lights: the aurora borealismay be visible across northern regions of the UK and the US tonight.
Typically speaking, the hotbed of aurora spotting is in countries such as Finland, Norway, and Iceland, but a recent solar storm could make the celestial spectacle appear further south.
AsDr Darren Baskill, an astronomy lecturer at the University of Sussex, told BBC Science Focus: "A large coronal mass ejection (CME) was recently emitted by the Sun – that’s the scientific way of saying that the Sun burped gas into space!
"That gas was emitted away from the Earth, so we won’t get a direct hit. However, it is possible that the very edge of this ejection will hit our planet, and this glancing blow may be enough to trigger some moderate auroral activity."
So, where exactly may the northern lights be visible? What causes them? And can solar flares damage our planet? All of this and more is answered below.
When can you see the northern lights?
There is a chance of seeing the northern lights tonight, Thursday 20 July, with moderate solar activity predicted.
The Met Office is reasonably confident of aurora sightings across Scotland, Northern Ireland, and in parts of northern England. Northern parts of Canada and the US (particularly Alaska) may also witness the northern lights.
But is anywhere guaranteed a sighting? "It’s very hard to say," says Baskill. "Current estimates indicate that this will cause moderate auroral activity, meaning that aurora may be visible over Scotland. It would have to reach high levels of auroral activity for observers in the rest of the UK and northern US states to see the Northern Lights."
However, you may be able to see more northern lights in the near future. "The Sun is now approaching the peak of its 11-year cycle of activity and will remain active for the next four years or so," says Baskill.
"While the current auroral forecast is only suggesting moderate auroral activity levels this week – which wouldn’t be enough to trigger widespread aurora over the UK – we will surely get some very impressive displays over the next few years as the Sun reaches its peak in activity."
How can I see the northern lights?
Your best bet for catching sight of the Northern Lights is when it’s dark and clear. Given the short hours of darkness in the summer, however, you’ll only have a brief period of opportunity to see the phenomenon in person.
The Shetland Islands is a classic location to spot the Northern Lights due to being far north and remote from elsewhere in the UK.
What causes the northern lights?
The Northern Lights are caused by solar activity in which electrically-charged high-energy particles from the Sun collide with low-energy particles within Earth’s upper atmosphere at a high speed. This is known as solar wind.
Solar geomagnetic storms take place on the Sun, which shoot these electrically-charged particles towards Earth. Some of them proceed to get trapped in the Earth’s magnetic field and get pushed towards the poles. The lights and colours of the auroras come from the particles from the Sun colliding with those in our upper atmosphere.
Why are the northern lights different colours?
The different colours of the Northern Lights are made up of different atoms in the Earth’s atmosphere. Depending on which atoms the solar energy reacts with, the colours we see in the auroras appear different.
Oxygen atoms at high altitudes, for example, cause the green colour of the aurora borealis. The blues, yellows, or reds you see are caused by lower-altitude oxygen or nitrogen atoms colliding with the electrically-charged solar particles.
Can solar flares cause any damage?
Solar flares can potentially cause some damage here on Earth, with particularly strong ones able to interfere with radio and satellite communications. Fortunately, the Earth’s magnetic field and atmosphere absorb most of the radiation from such events.
Short-wave radio signals are the main thing affected by strong solar flares, with the strongest of the lot increasing the ionisation of the upper atmosphere. Satellites, meanwhile, can potentially be damaged by solar flares.
Additional reporting by Noa Leach
About our expert
Dr Darren Baskill is an outreach officer and lecturer in the department of physics and astronomy at the University of Sussex. He previously lectured at the Royal Observatory Greenwich, where he also initiated the annual Astronomy Photographer of the Year competition.
