Feeds

Mystery of MAGNETIC ROCKS FOUND ON MOON cracked

Apollo 'nauts baffling finds caused by moon spoon dynamo

Build a business case: developing custom apps

Scientists say they may finally have cracked a long-standing boffinry conundrum – the mystery of why it is that the Moon rocks brought back by the Apollo astronauts of the 1960s and '70s are magnetic. The Moon, unlike the Earth, has no global magnetic field – a compass would not work on the lunar surface – and so its rocks shouldn't be magnetised. But they are.

Now, however, a crack team of boffins believe they may have unravelled the secrets of the remote lunar past and hit upon the cause of the mysterious Moon magnetisation. In essence, they believe that in the past the moon's liquid core may have been driven to spin and churn as Earth's does, generating a magnetic field in a similar fashion. The difference would have been that instead of being driven by heat from the inner core, as in the case of Earth, the smaller lunar core would have been set spinning by motion in the solid mantle covering it.

“This is a very different way of powering a dynamo ... [it] involves physical stirring, like stirring a bowl with a giant spoon,” says Christina Dwyer, grad student at the University of California and one of the team that solved the selenean puzzle.

The Moon is even today slowly receding outward from planet Earth, and has been doing so for a long time. Earlier in its history it was much closer to the mother planet, and tidal effects on the lunar mantle would have caused it to stir up the Moon's core and so generate a magnetic field. This in turn would have magnetised surface rocks, accounting for their condition when the Apollo astronauts found them.

But eventually, after a billion years or so, the Moon lost its magnetism.

“The further out the Moon moves, the slower the stirring, and at a certain point the lunar dynamo shuts off,” says Dwyer.

The scientists' research is published in hefty boffinry mag Nature. ®

Boost IT visibility and business value

More from The Register

next story
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
Flamewars in SPAAACE: cooler fires hint at energy efficiency
Experiment aboard ISS shows we should all chill out for cleaner engines
Brit amateur payload set to complete full circle around PLANET EARTH
Ultralight solar radio tracker in glorious 25,000km almost-space odyssey
NASA Mars rover FINALLY equals 1973 Soviet benchmark
Yet to surpass ancient Greek one, however
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.