There are doubts that a rock-like object found on a Mid Canterbury farm is a meteorite.
Police were called to a Dunsandel property south of Christchurch about it on Tuesday night.
On Wednesday scientists at the National Radiation Laboratory in Christchurch were asked by the prime minister's office to test the material, and to find out whether it is linked to the sonic boom in the South Island on Tuesday.
General manager Jim Turnbull says the object, that is the size of the person's palm is not radioactive, which means it is not a nuclear device from a space craft.
He says authorities wanted to know whether it was radioactive because there are old satellites that do have nuclear powered devices on them.
He says it is too light to be a meteorite and is possibly a fragment of space junk.
Turnbull says the object may be returned to the owner or handed over to geologists or staff at the University of Canterbury.
However he has not ruled out the fact that it may have something to do with Tuesday's sonic boom, which was so powerful it shook buildings across the Canterbury region and even registered on seismic drums used to monitor earthquakes.
Hundreds of people called police about the bang and several witnesses reported seeing the meteorite stream across the sky in Hinds. Seconds later it was spotted over Hanmer Springs in North Canterbury.
Many said the bang was so loud they thought it was a plane blowing up or an earthquake.
The meteor is the talk of much of the South Island.
Within hours of the sonic boom just before 3pm, a rash of objects had been posted on TradeMe claiming to be the meteorite responsible.
Experts say while the original rock was probably about the size of a large ball, it may have broken into pebble-size pieces.
Professor John Baggeley, who operates a meteor radar for Canterbury University, says finding it would be like looking for a needle in a haystack.
He says people expecting to find a smouldering rock will be disappointed as it will be cold now that it has come to Earth.
"We received about a hundred calls in a ten minute period - 25 percent of those were to the fire service, the rest were to police. Essentially all people could tell us was that they heard a loud bang," Inspector Mike Coulter says.
Police believe it was space junk re-entering the atmosphere, and there were no reports of damage.
A Canterbury astronomer says the meteor was probably travelling low and at great speed.
"When it hits the atmosphere it creates a ram phenomenon - that is the pressure of the atmosphere moving against it is what heats it up. Being so bright to be seen during the day and making a sound like a solar boom it would officially be called a bolite for astronomical purposes, which is an unusual event," associate professor at the Canterbury Astronomical Society, Euan Mason, says.
The last big meteor sighting in the South Island was in the Nelson region nearly two years ago.
