(Original headline: Close encounters of the Broxbourne kind )
Was it a bird, was it a plane, a shooting star or a real life UFO? Mercury readers have flooded our newsdesk with calls to tell how they spied a mysterious object in the skies over the borough.
After we told how a 29-year-old Hoddesdon man spotted an Unidentified Flying Object (UFO) from the Tower Centre flats in Hoddesdon, which he described as "six times the size of a shooting star with a massive tail like a fireball", plenty more readers have come forward to reveal they also saw the spectacle.
And to spook things up even more the Mercury has discovered that earlier on that SAME day, a UFO was apparently sighted in Dunstable, Bedfordshire, just 30 miles (48km) from Broxbourne borough.
On this occasion - around 3pm in the afternoon - according to the UFO sightings website UFO INFO, a local resident saw a "silver grey object coming from the south which was very high and slow moving".
Could the sightings be connected? Perhaps, but the Broxbourne UFO seemed to tear through the sky at a much faster pace.
Eye-witness Fiona Hagan actually fell off her chair when she saw the mysterious object dart through the sky while she was sitting in the front room of her friend's flat in Wormley.
The 43-year-old from Harlow, who was staying with her pal in Macers Lane that night, was relaxing on the settee when she looked out the window and saw the UFO at around 11.55pm. "It was really fast and so bright. It was like a bright green light with a tail," she said.
"I was so stunned that I fell off the settee. At first, for a split second I thought it might be a firework but then I realised it was too fast and too quiet to be a firework.
"I told my friend but she had been looking in the opposite direction and hadn't seen it - it was literally over in a flash."
Fiona added: "I wish I'd had a camera nearby to capture the sight. I feel really chuffed that I got to see it."
Stargazer Michael Weddle, from Broxbourne, also noticed the colourful fireball but believes it was a natural phenomenon rather than an alien encounter: "It was a shooting star as far as I'm concerned," he said.
"However it was a lot bigger than a usual shooting star - it was very prominent. It was the biggest I have seen, and there was another one shortly afterwards."
But fellow Broxbourne resident Celia Vogt, 55, wasn't so sure the mystifying object was simply a shooting star.
"I was relieved when I read the report in the Mercury on Friday about the man seeing the UFO as I'd been telling people what I'd seen and everyone thought I was mad," she said.
"I saw it just before midnight when I went outside to post a birthday card through my neighbour's door. I looked up and saw this amazing light in the sky. It was white with a tail
"It was too fast and too close to be a shooting star. It was huge."
Celia immediately texted Sky News on her mobile phone to ask if there were other reports of a UFO over Hertfordshire that night.
SO what was the UFO in the sky? The Mercury has contacted experts from the British Astrological Association (BAA) and discovered exactly what the mysterious manifestation was.
Neil Bone, director of the British Astronomical Association Meteor Section, told the Mercury: "I can confirm this was a fireball- in other words a very bright meteor or "shooting star".
"Fireballs aren't especially rare but occur rarely in good weather - as was the case for this event and this one looks to have been over the southern North Sea - maybe off the Dutch coast.
"The incoming body was probably rock in nature, orientating from the asteroid belt between Mars and Jupiter and thrown into an Earth-crossing orbit by a collision which occurred tens or hundreds of thousand of years ago before eventually being swept up.
"I hope this clarifies the situation - it was not a UFO but something quite natural and reasonably (though not especially) common."
