'Wavy' glow that 'looked like Northern Lights' seen in Bristol skies

A mysterious 'wavy' light formation seen in the sky near Bristol has been explained, after a witness thought they had spotted the Northern Lights. Footage shared with Bristol Live showed an eerie glow with a blue-green tinge, seen above roof tops in Emersons Green last night (Sunday, August 20).

The eyewitness, who preferred not to be named, said: "My partner took the video on his way to collect me from work at roughly 10.10pm from Emersons Green Park. He saw the purple/blue light out of the corner of his eye and kept watching it because he was confused about what it was.

"He got me from work and we hurried back to the park so I could see it but it was barely visible by the time we got there about 10.40pm. We aren’t too sure what it was now but we would like to find out."

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She said they initially thought it was the Northern Lights, due to the colour and movement. The spectacle is rare to see so far south in the UK, although they were spotted on several occasions at the start of the year.

The Northern Lights are most active during the Equinox and Solstice in March/April and September/October, according to the Met Office, so an August sighting in our area would be unusual but not impossible. However, there were no other UK sightings last night and it seems there is another explanation.

Given previous confusion about blue-tinged lights in the night sky, which ended up being the light from a special type of train, Bristol Live approached Network Rail to check the possibility of this being the case again. The witness said she had considered this possibility, but has seen that light before and this seemed different.

She added: "The possibility of it being a [train] light did cross his mind but instead of a solid beam it was wavy and flickering. It was transitioning between purples, blues, neon greens and oranges.

"I saw the [train] beams a couple years back. These were wavy rather than a straight line and I’m not sure if the train lights have a neon green or just the blue."

However, Network Rail has confirmed that it was indeed carrying out engineering work in the area at that time, and that the light is 'likely to be from one of our high-tech trains that’s used to carry out track and infrastructure work'.

The train is called the New Measurement Train (NMT), also known as the 'Flying Banana' thanks to its yellow colour and high speeds of up to 125mph. It monitors and records track condition information, to locate and identify faults before they become a safety issue or affect performance.

Back in 2019, Network Rail explained that under certain conditions - thin, relatively low cloud - the light emitted by the train bounces back off the cloud and creates the appearance that there is something blue in the cloud itself. Previous sightings have shown a much more obvious bright blue colour, but this time the more subtle shade and shift to a green-yellow did give the illusion of the Northern Lights.