The northern lights could be visible across parts of the UK on Thursday night.
The Met Office forecast suggests the aurora borealis could be visible to the naked eye along the northern horizon from Scotland, where skies are clear, and may be seen briefly in Northern Ireland and northern England.
A minor enhancement to the auroral oval – the range of the polar lights – is responsible for the display being visible so far south this week.
The lights were seen over Northumberland on Wednesday night. The activity is expected to start subsiding from Saturday.
Prof Don Pollacco, a physicist at the University of Warwick, said it would be difficult to predict exactly where the northern lights would be visible as conditions could change quickly.
“However, one thing is for sure and that is that you are unlikely to see them from a brightly lit city environment – you need to go somewhere dark and look towards the northern horizon (look for the North Star),” he said. “So, you would preferably be in the countryside away from street lights. Of course it also needs to be clear.”
The light spectacle is usually most visible near Earth’s magnetic north and south poles, where the lights are called the aurora australis.
The lights are caused by the interaction of particles coming from the sun – the solar wind – channelled to the polar regions by the planet’s magnetic field, with Earth’s atmosphere.
Depending on which gas molecules are hit and where they are in the atmosphere, different amounts of energy are released as different wavelengths of light, with oxygen producing green light and nitrogen causing the sky to glow red.
Pollacco said: “It’s actually a bit like iron filings and the field of a bar magnet. The solar wind contains more particles when there are sunspots, as these are regions on the sun’s surface where the magnetic field is interacting with the plasma in the sun, and the particles can be released.
“Once the particles are channelled into the Earth’s atmosphere, they interact with molecules and have distinctive colours and patterns such as light emissions that look like curtains or spotlights. These shapes change quickly over timescales of minutes/seconds.”
In February, the northern lights appeared in the night sky across much of Britain, as far south as Hertfordshire and Cornwall.
PA Media contributed to this report
