This flip of the magnetic poles would have been devastating, creating extreme weather and possibly leading to the extinction of large mammals and the Neanderthals. The magnetic poles wander and occasionally reverse around every , to , years, but we have little evidence on how this impacts our planet. Alan Cooper at the South Australian Museum in Adelaide and his colleagues have now provided some answers.
The team calculated this using radiocarbon analysis of tree rings from an ancient, fossilised kauri tree Agathis australis preserved in northern New Zealand wetlands. When the magnetic field weakens, more cosmic rays enter the atmosphere and transform certain atoms into radioactive carbon, raising levels of this isotope.
They also had no way of confirming that it had happened, so there was great doubt about his finding. As a result, he never published again on the topic and died a few years later of a massive stroke at the age of But this was the first signal that the heart of the molten outer core of our planet is much more tortured than scientists had imagined.
Constant movement within the outer core is what creates our magnetic field. What Lathrop is trying to do is re-create the dynamo that we believe exists inside the core of the Earth. We know that the core is becoming increasingly volatile. The North magnetic pole is absolutely running through the Northern Hemisphere at 55 kilometers a year to the northwest.
We also know that the dipole is weakening fairly dramatically. If you look at satellite imagery, you can see that part of the magnetic field has already reversed in the Southern Hemisphere. This is something called the South Atlantic Anomaly. Does that tell us that a reversal is at hand?
Scientists simply do not have enough information to make that conclusion. The consequences for life on Earth are potentially devastating. What if one of those bands of extra radiation hits a very heavily populated part of the planet? Then, of course, there are the effects on all the creatures on the planet, as well as the effects on our electromagnetic system, the electric grid, and all the things we consider part of modern civilization.
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Go Further. Animals Climate change is shrinking many Amazonian birds. However, we know that a flip doesn't happen overnight. Instead, it takes anywhere from a century to 20, years to complete, and it's accompanied by a decline in strength of the magnetic field. Based on measurements that began in the mids, we're in the midst of one such weakening right now, and in , data from European Space Agency satellites revealed that the magnetic field loses 5 percent of its strength with every passing decade [source: Sneed ].
Some say the decline could stop at any time — the strength of the magnetic field today is still stronger than it's been for most of the last 50, years — while others says it's an indicator that the magnetic field will flip within the next 1, years. Besides today's compasses pointing south instead of north, what would happen if the magnetic field flipped? While the atmosphere would still help shield the planet from radiation, the weakening of the magnetic field that precedes the reversal could make us vulnerable to cancer-causing energy particles and cosmic rays [source: Sanders ].
A flipped magnetic field could seriously disrupt communications systems and power grids. It could also produce multiple north and south poles, and birds, whales and other migratory animals that use the field to establish a sense of direction could encounter problems. That said, a reversal of the poles probably doesn't necessarily spell certain doom for humanity: There's no evidence that past flips of the magnetic field caused mass extinctions or other catastrophes.
You'll definitely need a new compass though. Sign up for our Newsletter! Mobile Newsletter banner close.
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