Further confirmation of 2012?

The Sun operates on an 11-year cycle, alternating between active and quiet periods. We are currently in a quiet period, with few sunspots on the sun’s surface and fewer solar flares, though the next cycle of activity has begun. It is expected to peak around 2012, bringing lots of sunspots, flares and coronal mass ejections (CMEs). CMEs can interact with the Earth’s magnetosphere, causing problems for satellites, communications, and power grids.

This upcoming active period now looks like it will be more intense than the previous one, which peaked around 2006, some scientists think. The reason is the changes in the sun’s alignment.

During the last peak, solar fields hitting the Earth were first anti-aligned then aligned. Anti-aligned fields can energize particles, but in this case, the energy came before the particles themselves, which doesn’t create much of a fuss in terms of geomagnetic storms and disruptions.

But the next cycle will see aligned, then anti-aligned fields, in theory amplifying the effects of the storms as they hit.

Raeder likens the difference to igniting a gas stove one of two ways: In the first way, the gas is turned on and the stove is lit and you get a flame. In the other way, you let the gas run for awhile, so that when you add the gas you get a much bigger boom.

“It should be that we’re in for a tough time in the next 11 years,” Sibeck said.

http://www.space.com/scienceastronomy/081216-agu-solar-storm-shield-break.html

The years ahead could be especially lively. Raeder explains: “We’re entering Solar Cycle 24. For reasons not fully understood, CMEs in even-numbered solar cycles (like 24) tend to hit Earth with a leading edge that is magnetized north. Such a CME should open a breach and load the magnetosphere with plasma just before the storm gets underway. It’s the perfect sequence for a really big event.”

Sibeck agrees. “This could result in stronger geomagnetic storms than we have seen in many years.”

http://science.nasa.gov/headlines/y2008/16dec_giantbreach.htm?list889783

Sloshing Inside Earth Changes Protective Magnetic Field

Something beneath the surface is changing Earth’s protective magnetic field, which may leave satellites and other space assets vulnerable to high-energy radiation.

The gradual weakening of the overall magnetic field can take hundreds and even thousands of years. But smaller, more rapid fluctuations within months may leave satellites unprotected and catch scientists off guard, new research finds.

A new model uses satellite data from the past nine years to show how sudden fluid motions within the Earth’s core can alter the magnetic envelope around our planet. This represents the first time that researchers have been able to detect such rapid magnetic field changes taking place over just a few months.

“There are these changes in the South Atlantic, an area where the magnetic field has the smallest envelope at one third [of what is] normal,” said Mioara Mandea, a geophysicist at the GFZ German Research Center for Geosciences in Potsdam, Germany.

Even before the newly detected changes, the South Atlantic Anomaly represented a weak spot in the magnetic field — a dent in Earth’s protective bubble.

Bubble bobble

The Earth’s magnetic field extends about 36,000 miles (58,000 km) into space, generated from the spinning effect of the electrically-conductive core that acts something like a giant electromagnet. The field creates a tear-drop shaped bubble that has constantly shielded life on Earth against much of the high-energy radiation flowing from the sun.

The last major change in the field took place some 780,000 years ago during a magnetic reversal, although such reversals seem to occur more often on average. A flip in the north and south poles typically involves a weakening in the magnetic field, followed by a period of rapid recovery and reorganization of opposite polarity.

Some studies in recent years have suggested the next reversal might be imminent, but the jury is out on that question.

Measuring interactions between the magnetic field and the molten iron core 1,864 miles (3,000 km) down has proven difficult in the past, but the constant observations of satellites such as CHAMP and Orsted have begun to bring the picture into focus.

Electric storm

Mandea worked with Nils Olsen, a geophysicist at the University of Copenhagen in Denmark, to create a model of the fluid core that fits with the magnetic field changes detected by the satellites.

However, the rapid weakening of the magnetic field in the South Atlantic Anomaly region could signal future troubles for such satellites. Radiation storms from the sun could fry electronic equipment on satellites that suddenly lacked the protective cover of a rapidly changing magnetic field.

“For satellites, this could be a problem,” Mandea told SPACE.com. “If there are magnetic storms and high-energy particles coming from the sun, the satellites could be affected and their connections could be lost.”

The constant radiation bombardment from the sun blows with the solar wind to Earth, where it flows against and around the magnetic field. The effect creates the tear-drop shaped magnetosphere bubble, but even the powerful field cannot keep out all the high-energy particles.

Topsy-turvy history

A large sunspot set off a major radiation storm in 2006 that temporarily blinded some sun-watching satellites. Astronauts on the International Space Station retreated to a protected area as a precaution to avoid unnecessary radiation exposure.

The Earth’s overall magnetic field has weakened at least 10 percent over the past 150 years, which could also point to an upcoming field reversal.

Mandea and Olsen hope to continue refining their model with updated observations, and perhaps to eventually help predict future changes in the Earth’s magnetic field.

The study was detailed in the May online edition of the journal Nature Geoscience.

http://www.space.com/scienceastronomy/080818-mm-earth-core.html