Still no sign of meteorite which crashed down near Dunedin last month

A search of farmland near Dunedin has been unable to unearth any remnants of the meteorite which crashed down last month.

Those behind the search say it is now unlikely it will be found, but a tenacious optimist still holds out hope.

A team of 20 scoured for the elusive alien rock about a fortnight ago, before 50 searchers combed a farm near Dunedin on Friday and a similar number of students gave it one last go over the weekend.

University of Canterbury senior lecturer Dr Michele Bannister said the rock was essentially a time capsule.

"This is a building block of the material that went into making the planets - just like the one we're walking across four-and-a-half billion years later," Dr Bannister said.

That was why the meteorite was so valuable to scientists - it could tell them much about the universe.

"Our planet has wind, it has weather, it has storms, it has erosion, it has biology - it has all of these wonderful processes modifying its interior and its surface and the landscapes we see today. But a meteorite, the source material of that - the asteroids or the comets - that hasn't experienced any of that, so it allows us to look back at what things were like when the planets were being born."

Unfortunately those secrets would remain hidden for some time yet, as the search was unable to unearth any remnants of the meteorite.

University of Otago geologist Marshall Palmer, who co-ordinated the search, said it was an unsurprising outcome considering searchers were trying to track down something potentially as small as a pebble across thousands of metres of farmland.

"I think it would be quite easy to find a needle in a hay stack - you could just wave a magnet through it. But a meteorite is a whole order of magnitude above that," he said.

"I still feel like the meteorite is out there and if you get out there on the weekends and have a bit of a nosey, there's still a small possibility that we will find it. But the fact we've had so many people scouring over the ground, it does make the probability of finding it seem a lot lower."

But he had not given up hope and intended on returning with a metal detector in future.

The meteor was spotted coming into the Earth's atmosphere by cameras set up by Fireballs Aotearoa.

The network had only been online for months, with the most recent cameras set up in Southland only a week before it came down.

Fireballs Aotearoa research assistant Thomas Stevenson said the network had already proven its value.

"It's very fortuitous timing for us that we had those cameras in place because without them we wouldn't have got that neat triangulation and that really confined search area."