Earth’s Magnetic Field Made Quick Flip- Flop
2012-10-24 0:00

Byh Charles Q. Choi | LiveScience.com





Earth’s magnetic field reversed extremely rapidly soon after modern humans first arrived in Europe, completely flip-flopping in less than a thousand years, new research suggests.

These findings, detailed Oct. 15 in the journal Earth and Planetary Science Letters,could shed light on how and why magnetic field reversals happen, and how they leave Earth vulnerable to solar and space radiation, the study scientists said.

Earth’s metal core acts like a giant magnet that emanates a magnetic field with two poles, north and south. These two magnetic poles very roughly match where the planet’s geographic north and south poles lie, which mark the axis on which Earth spins.


The Earth’s magnetic field, magnetic poles and geographic poles.

"The Earth’s magnetic field is a highly dynamic feature," said researcher Norbert Nowaczyk, a paleomagnetist at the GFZ German Research Centre for Geosciences. "Its intensity pulsates between values 50 percent higher than today, or 90 to 95 percent lower than today."

In addition, every several hundred thousand years, Earth’s magnetic field reverses — a compass that would have pointed north would instead aim south. These flips are captured by magnetically sensitive minerals in cooling lava that are literally set in stone pointing to where the poles were at that particular moment in Earth’s history.

Failed reversals

Full reversals of the magnetic field usually take millennia to finish, based on those frozen rock records. However, scientists now find that 41,000 years ago, shortly after modern humans first entered Europe, the magnetic poles flipped and flipped again in less than a millennium.

Scientists analyzed data in sediment from the floor of the Black Sea and compared it with other data from the North Atlantic, the Southeast Pacific and around Hawaii. Surprisingly, they found the Earth’s magnetic field took about 200 years to flip, during which time it was just one-twentieth as strong as it is today.

"Former ideas about a field reversal deal with durations of 2,000 to 5,000 years," Nowaczyk told OurAmazingPlanet.

Earth’s magnetic field stayed reversed for only 440 years, during which time it was just one-quarter as strong as it is today. The magnetic poles then flipped back to approximately where they were before over the course of about 270 years. The flip-flop overall is known as the Laschamp event, after the area in France where evidence of it was first discoveredin the 1960s. These new findings reveal how quick this reversal was.




The brevity of this flip overall suggests "it might represent a so-called aborted reversal," Nowaczyk said. "This means the geomagnetic field tried to reverse, but fell back." Such aborted reversals, also known as excursions, may have happened at least a dozen times during the last 780,000 years since the last full reversal, he explained.

Magnetic field shield

Earth’s magnetic field helps protect the planet from energetic particles streaking out from deep space and the sun. During the Laschamp reversal, Earth was significantly more vulnerable to radiation from space, judging by higher levels of radioactive beryllium seen in ice samples from Greenland, Nowaczyk said.

Such radiation poses a particular threat in our modern world, so understanding these reversals is helpful to better understand the threats from space.

"Communication and GPS satellites might be damaged when the cosmic rays are less shielded by the geomagnetic field," Nowaczyk said. "Therefore, it is important to know how dynamic the geomagnetic field is in time and space. We need to know how fast changes in intensity, and thus shielding ability, can happen."

Earth’s magnetic field is generated by the roiling of its outer liquid core. Research suggests that at times this outer core can behave as many magnets instead of one. These magnets can, in principle, cancel each other out, causing the magnetic field overall to weaken or flip.

"We need more data from more sites of the same reversal to get a better understanding of these processes," Nowacyzk said.


Article from: livescience.com





Tune into Red Ice Radio:

Robert Felix - Magnetic Reversal and Evolutionary Leaps

Robert Felix - The Coming Ice Age

Paul A. LaViolette - Earth Under Fire, Galactic Superwaves & Subquantum Kinetics

Susan Joy Rennison - A New Cosmic Age, Space Weather & Cosmic Radiation

Wallace Thornhill - The Electric Universe



Donald E. Scott - The Electric Sky

Randall Carlson - Hour 1 - Cycles of Catastrophe & Cosmic Patterns







Related Articles
Scientist Finds Hidden Portals in Earth’s Magnetic Field
Electrical Engineer Can Feel Magnetic Fields Through Magnets Implanted in His Fingertips
Magnetic polar shift on the sun underway
Moon Oddly Magnetic—Giant Asteroid Crash to Blame?
What If Earth’s Magnetic Poles Flip?
Humans May Have ’Magnetic’ Sixth Sense
Flamingos Drop From Siberian Sky: Locals Mystified (Magnetic Fields Reversing?)
Foxes see Earth’s magnetic field and use it to target prey
Birds use quantum theory to literally ’see’ Earth’s magnetic field as they fly


Latest News from our Front Page

41% of Americans Support Criminalizing "Hate Speech"
2015-05-23 7:31
The following are from a recent poll about what some are calling on for "hate speech" 1. Support for Hate Crimes Legislation Do you support or oppose the federal law that requires increased penalties for hate crimes committed on the basis of the actual or perceived race, color, religion, national origin, ethnicity, or gender of any person? 2. Support for Expanding Hate Crimes Do ...
FBI Admits No Major Cases Cracked with Patriot Act Snooping Powers
2015-05-23 7:36
FBI agents can’t point to any major terrorism cases they’ve cracked thanks to the key snooping powers in the Patriot Act, the Justice Department’s inspector general said in a report Thursday that could complicate efforts to keep key parts of the law operating. Inspector General Michael E. Horowitz said that between 2004 and 2009, the FBI tripled its use of bulk ...
Sweetener Stevia Was Once Hailed As An Anti-Fertility Agent for Population Reduction
2015-05-23 7:13
Maybe it's not so sweet now... If you've thought stevia, the natural alternative to sugar and artificial sweetners with aspartame, et al., is too good to be true, there may be a catch. Check out this textbook written in 1970 by Paul and Anne Ehrlich, the precursor to the textbook Ecoscience they wrote with Obama Science Czar John P. Holdren ...
TPP Aproved: Senate Republicans Give Obama New Powers - Details Remain 'Classified'
2015-05-23 6:43
President Obama won a big victory for his trade agenda Friday with the Senate’s approval of fast-track legislation that could make it easier for him to complete a wide-ranging trade deal that would include 11 Pacific Rim nations. A coalition of 48 Senate Republicans and 14 Democrats voted for Trade Promotion Authority late Friday, sending the legislation to a difficult fight ...
Circumcision battle: Mom seeks release from jail after federal lawsuit is dismissed
2015-05-23 3:22
West Boynton mother on Wednesday gave up trying to get a federal judge to stop her 4 1/2-year-old son from being circumcised as his father wishes — a battle that also led to her arrest May 14 on a state court warrant. An attorney for Heather Hironimus, who lost similar legal challenges in two state courts, notified U.S. District Judge Kenneth ...
More News »