SCIENTIFIC explanations have been offered for the spooky lights which have been causing a stir across Calderdale.
Courier readers have reported seeing strange lights in the skies above Mytholmroyd.
Read last week's story - click here.
The lights were seen between 8pm and 9pm last Monday, while others saw them in Greetland last week and two weeks before in Todmorden.
But now other residents have contacted the Courier with their ideas as to what the suspected UFOs could be and astrological experts have also tried to solve the mystery.
Two people suggested the bright spots in the skies could be attributed to an annual natural phenomenon.
Reader James Fryer said: "I'm certainly no expert, but I believe the lights were probably part of the annual meteor shower known as the Perseids."
The showers, which are active from July 17 to August 24 this year and reached their peak on August 12, are caused by small bits of debris that enter the Earth's atmosphere when our orbit passes through the tail of the Swift-Tuttle comet. These particles travel at very high speeds, reaching up to 32 miles per second and burn up in the atmosphere.
This causes the air around them to get extremely hot, which produces the visible streak of light.
Tony Doubtfire, from the West Yorkshire Astronomical Society, said the Perseids could be one possible explanation for the Calderdale mystery.
"It is like a shower of sparks streaking across the sky."
But he also suggested our readers could have spotted Jupiter or a space station: "Jupiter is very bright at the moment and might be visible if you look due south at around 10pm."
Another reader contacted us, saying: "It could be a model helicopter, if powered by electric, then there would not be any sound depending on the distance and altitude from it."