November 2015 – EARTH – Earth’s magnetic field is not about to flip. While the intensity of this field has weakened in the last couple hundred of years, researchers have found that this doesn’t mean it’s about to reverse. Humans have lived through dips in magnetic field intensity before. However, there are debates about whether reversals of the magnetic field in the distant past had any connection to species extinctions. Today, a magnetic field reversal would have a huge impact due to one very important thing: technology. The magnetic field deflects the solar wind and cosmic rays. This means that with a weaker field, more radiation gets through which can disrupt power grids and satellite communications.
“The field may be decreasing rapidly, but we’re not yet down to the long-term average,” said Dennis Kent, one of the researchers, in a news release. “In 100 years, the field may even go back the other direction [in intensity].” In this latest study, the researchers used a new technique to measure changes in the magnetic field’s strength in the past and found that its long-term average intensity over the past five million years was much weaker than the global database of paleointensity suggests-only about 60 percent of the field’s strength today. This suggests that today’s magnetic field may be unusual since it’s much stronger than the average.
Scientists have long thought the decline in the magnetic field-about 10 percent over the past two centuries-could mean that another reversal may be coming. In this case, though, the researchers found that dips occur frequently, and this doesn’t mean that a reversal will be the result. The findings are published in the journal Proceedings of the National Academy of Sciences. –Science World Report