<p>The weakening intensity of the Earth's magnetic field may actually be coming down to normal rather than approaching a reversal, a new study says.<br /><br /></p>.<p>The intensity of the Earth's magnetic field has been weakening for the last couple of hundred years, leading some scientists to think that its polarity might be about to flip.<br /><br />But now scientists said the field's intensity may simply be coming down from an abnormal high rather than approaching a reversal.<br /><br />The weakening of the Earth's magnetic field would affect technology.<br /><br />The magnetic field deflects the solar wind and cosmic rays. When the field is weaker, more radiation gets through, which can disrupt power grids and satellite communications.<br /><br />"The field may be decreasing rapidly, but we are not yet down to the long-term average. In 100 years, the field may even go back the other direction [in intensity]," said study co-author Dennis Kent from Columbia University's Lamont-Doherty Earth Observatory.<br /><br />The scientists 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.<br /><br />The findings raise questions both about claims that the magnetic field may be nearing a reversal.<br /><br />The study's results fit expectations that the magnetic field's intensity at the poles should be twice its intensity at the equator.<br /><br />In contrast, the time-averaged intensity calculated from the PINT paleointensity database doesn't meet the two-to-one, poles-to-equator dipole hypothesis, and the database calculation suggests that the long-term average intensity over the past five million years is similar to the field's intensity today.<br /><br />The study appeared the journal Proceedings of the National Academy of Sciences.<br /></p>
<p>The weakening intensity of the Earth's magnetic field may actually be coming down to normal rather than approaching a reversal, a new study says.<br /><br /></p>.<p>The intensity of the Earth's magnetic field has been weakening for the last couple of hundred years, leading some scientists to think that its polarity might be about to flip.<br /><br />But now scientists said the field's intensity may simply be coming down from an abnormal high rather than approaching a reversal.<br /><br />The weakening of the Earth's magnetic field would affect technology.<br /><br />The magnetic field deflects the solar wind and cosmic rays. When the field is weaker, more radiation gets through, which can disrupt power grids and satellite communications.<br /><br />"The field may be decreasing rapidly, but we are not yet down to the long-term average. In 100 years, the field may even go back the other direction [in intensity]," said study co-author Dennis Kent from Columbia University's Lamont-Doherty Earth Observatory.<br /><br />The scientists 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.<br /><br />The findings raise questions both about claims that the magnetic field may be nearing a reversal.<br /><br />The study's results fit expectations that the magnetic field's intensity at the poles should be twice its intensity at the equator.<br /><br />In contrast, the time-averaged intensity calculated from the PINT paleointensity database doesn't meet the two-to-one, poles-to-equator dipole hypothesis, and the database calculation suggests that the long-term average intensity over the past five million years is similar to the field's intensity today.<br /><br />The study appeared the journal Proceedings of the National Academy of Sciences.<br /></p>