A strange light filmed in the sky over Auckland on Saturday night was probably not a UFO, comet, or rogue planet about to smash into Earth, astronomers say.
The descending point of light, which revealed a U-shaped nimbus when zoomed in on, was filmed in the sky west of Auckland about 6pm on Saturday.
The video was uploaded to YouTube by a user known as biggordy100 who narrates that the light is "back", indicating he has seen it in the past.
The tag-line on the video reads: "WTF is in our skies? ufo! nibiru? elenin? spaceship? comet? seen over Auckland at 18.00."
Nibiru is the name given by Doomsday and conspiracy blogs and websites to a supposed collision between Earth and a mystery planet - Planet X - that is supposed to occur in the early 21st Century.
According to Wikipedia, Nibiru was revealed to Wisconsin woman Nancy Lieder after aliens implanted a communications device in her brain.
Comet Elenin has a similar conspiracy theory attached to it - something about it actually being a secret brown dwarf star that is going to flip the Earth's magnetic polarity with disastrous results.
Astronomers who could be bothered have debunked both theories.
Astronomy educator at Auckland's Stardome Observatory, David Britten, said Nibiru would not hit Earth "because it doesn't exist".
He said the light that had been filmed was "almost certainly the contrails of a plane heading out over the Tasman Sea".
Britten said at that time, the sun had set enough for Auckland to be in shadow but the plane was still in the sun.
Its spreading contrail was catching the light and making the effect recorded.
Britten said the observatory was approached about similar sights semi-regularly.
"Look at the coverage over Hurricane Irene - if there was something out there that was going to hurt us, we would know about it.''
He said if the videographer had waited for dark, with a telescope he might have seen Saturn and its rings in approximately the same spot.