A naturally occurring phenomenon, the northern lights are a spectacular sight to see. But for those in the UK, you might not have to travel far to spot them tonight.
According to recent observations of solar weather, the auroras could be visible over the next couple of days across the skies of the British Isles.
Normally, you need to travel to certain countries such as Finland, Iceland or Norway to see them. While not as clear as in other parts of the globe, the northern lights can be witnessed across the UK. However, the farther north you are, the easier they are to see.
On Monday 25 September, the northern lights entertained stargazers across Scotland and northern England.
So how can you increase your chances of seeing the auroras? When is the best time to see them and what actually are the northern lights?
When can you see the northern lights?
The northern lights may be visible tonight, Thursday 26 September, with the best viewing time between 10pm and midnight.
The exact time is uncertain, and there is no guarantee that the auroras will make an appearance. Observations by The Met Office have indicated that while sightings are certainly "possible" tonight, most activity will be restricted to northern parts of the UK.
In the past seven days, however, the auroras have been spotted in areas as south as Hertfordshire.
“The visibility of the northern lights in the UK depends on the interaction between the solar wind and the Earth's magnetosphere, which is very much out of our control,” explains Paul Strom, assistant professor in the department of physics at Warwick University.
“Factors like daylight, cloud cover, and light pollution affect visibility, with the statistically best viewing time being between 10pm and midnight due to peak auroral activity during that period.”
To make sure you don't miss a sudden flare-up, Strom advises signing up to alerts from Aurora Watch, built by Lancaster University.
Tips to increase your chances of seeing the northern lights
"When conditions are favourable, the northern lights can be observed from any location within the UK, with better chances in northern regions,” says Strom.
“To witness this phenomenon, one should seek a dark, light pollution-free location with an unobstructed northern horizon, preferably from an elevated spot like a hill.”
It is also worth noting that the lights are unlikely to look like they do on social media. Most popular images have been edited or captured using long-exposure camera settings. In reality, the lights could be hard to see or not fully visible, even in a dark environment.
What causes the northern lights to form?
The northern lights are caused by solar activity. High-energy particles that come from the Sun collide with low-energy particles in the Earth’s atmosphere.
Additional energy that is generated during a geomagnetic storm pushes the aurora further south than usual. Geomagnetic storms are rare but occur more frequently during declining phases of the solar cycle.
During this stage, coronal holes (areas of low density) on the Sun’s equator create powerful solar winds (streams of charged particles that batter the Earth.)
It is the resulting disturbance to Earth’s magnetic field that increases the likelihood of auroras, as high-energy particles are more likely to collide. In fact, without Earth's atmosphere, the solar wind streams would destroy life as we know it – instead, the particles are redirected towards the poles.
Why are the northern lights different colours?
There are two primary gases in the atmosphere of Earth – nitrogen and oxygen. During an aurora display, these elements release different colours. When we see green in the aurora, that comes from the characteristic of oxygen.
However, purple, blue, or pink hues in the night sky are caused by nitrogen. The colours depend on which of the atoms are reacting with the solar energy at the given time.
What does 'aurora borealis' mean?
A term you may have heard before in connection to the northern lights, aurora borealis means ‘dawn of the northern winds’. This is the original name of the northern lights and refers to Boreas – the god of the north wind in Ancient Greek mythology.
It isn’t just the northern lights though, there is also the aurora australis, also known as the southern lights. These are unsurprisingly witnessed from countries in the southern hemisphere.
About our expert, Dr Paul Strom
Strom is an Assistant Professor at Warwick University working on the PLATO space mission. He also works on a variety of astrophysical topics mainly focused on far-UV observations aimed at understanding the the formation environments of young planets.
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