Earth’s Magnetic Field Flipped Superfast

Magnetic minerals in 15-million-year-old rocks appear to preserve a moment when the magnetic north pole was rapidly on its way to becoming the south pole, and vice versa. Such “geomagnetic field reversals” occur every couple hundred thousand years, normally taking about 4,000 years to make the change. The Nevada rocks suggest that this particular switch happened at a remarkably fast clip.

The last stable reversal occurred 780,000 years ago. Some geologists argue the Earth is overdue for a reversal and might even be entering one now, as the geomagnetic field has been getting weaker over the past 150 years or more.

Article:
http://www.wired.com/wiredscience/2010/09/superfast-magnetic-reversal/

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Space ribbon deployed to surf Earth's magnetic field

A Japanese rocket unfurled a 300-metre-long ribbon in space on Monday, testing technology that could one day allow spacecraft to navigate by surfing Earth's magnetic field.

Conventional spacecraft have to burn fuel to manoeuvre in orbit. But the fuel adds weight and cost to the launch and eventually gets used up, limiting the probes' lifetime.

In principle, it is possible to propel an orbiting spacecraft without fuel by using a long piece of metal to interact with the magnetic field surrounding our planet. "You're essentially pushing against the Earth's magnetic field," says Les Johnson of NASA's Marshall Space Flight Center in Huntsville, Alabama.

Article:
http://www.newscientist.com/article/dn19393-space-ribbon-deployed-to-sur...

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This illustration depicts coronal mass ejections, or bursts of solar wind, coming off the Sun's surface heading toward Earth. The blue paths from the Earth's poles represent some magnetic field lines. By the time they reach earth, these magnetic cloud of plasma can grow to 30 million miles in width, disrupting communications and navigational equipment, damage satellites, and even cause blackouts.

Video: http://www.cbsnews.com/2300-205_162-10004703.html

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