She admits it sounds nutty.

But Janine Coburn swears she spotted a fiery green orb streaking across a clear night sky on the weekend. It was moving faster than an airplane, Coburn insists, and it was bigger than a falling star.

"It's as if it were flung by a giant," she said. "It was vivid."

The Somerset resident was out for some fresh air shortly before midnight on Sunday when she watched the mysterious object soaring north for at least five seconds before vanishing.

It's left Coburn scratching her head to explain the apparent cosmic show. Combing through online communities has been fruitless, so she's asking Calgarians for answers.

"I've done research since then and it hasn't made me feel any more comfortable with what I saw," she said Tuesday.

Phil Langill, director of the University of Calgary's observatory, is also unsure what Coburn witnessed. Photos pulled from a sky camera reveal Sunday was actually a cloudy evening, which leads Langill to believe it was a low-flying object - possibly fireworks.

"If it were below the clouds it would've been man-made," he said. "If it were above the clouds it could've been a meteor."

Experts predicted rural skywatchers could have seen as many as 100 shooting stars per hour during the Geminid meteor showers, which peaked last Friday.

Devon Hamilton, a PhD in astrophysics, suggested the local sighting was a highly visible meteor known as a fireball, based on Coburn's loose account.

A highly charged meteor often emits distinct colours as it passes through Earth's atmosphere, according to Hamilton, a vice-president with the Telus Spark science centre.

"In the case of green meteors, the composition can be connected to nickel," he said. "Although other factors can contribute to the coloration, including tricks our eyes and brains play on us."