AS scientists around the world grapple with the possibility that Earth's magnetic field is heading for a reversal, Australia is to enhance international investigations with a new magnetic field observatory north of Perth at Gingin.

Dr Adrian Hitchman of Geoscience Australia says it will be another 12 months before the observatory is fully operational but when working, it will keep a second by second, 24-hour monitor of the apparently weakening magnetic field.

"The jury is still out on the implications of the weakening field," he says.

"But some researchers have flagged the possibility that the weakening may be associated with the commencement of a field reversal.

"Another possibility, of course, is that this is simply a relatively short-term (by Earth standards) trend that may 'right' itself in time."

The possibility of a reversal is causing considerable scientific speculation and an upsurge in spending to discover what might be going on, including the focusing of attention on the world's remotest inhabited island.

Changes in the planet’s magnetic field happen every day, every hour and even every second.

"Short-term changes are caused in a variety of ways by the Sun," Dr Hitchman says.

"Long-term changes, over thousands of years, are caused by fluid motion in Earth's outer core."

It is what is happening in the Earth's core that is causing the field to weaken and scientists speculate that the magnetic field may be heading for a flip - or even that it will ‘disappear’.

Paleomagnetic research suggests that reversals, when compass needles switch from north to south, could be happening every 500,000 years.

The impact of such an event on today's world is hard to imagine. It is not just ships, planes and satellites that would be affected. Many animals are believed to use the magnetic field to navigate.

Scientists have also speculated that major changes to the field could make the hole in the ozone layer larger, disrupt communications systems and interfere with power grids. 

They all appear to agree that no major change is expected any time soon, and that if and when a flip begins, it could take 5000 years to complete. 

For the new $180,000 facility at Gingin, not all its time will be spent searching for evidence of a flip.

According to Dr Hitchman, the Gingin instrument will be one of a network of nine magnetic observatories operated by Geoscience Australia (GA) - six in Australia and three in Antarctica.

Together the network enables GA to offer services in space weather forecasting, navigation, and resources exploration.