EVERYDAY SCIENCE

Detailed explanation-1: -The best answer is option 4. Earth’s magnetic field is powered by the core of the planet.

Detailed explanation-2: -Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200, 000 to 300, 000 years, although it has been more than twice that long since the last reversal. A reversal happens over hundreds or thousands of years, and it is not exactly a clean back flip.

Detailed explanation-3: -Magnetic Pole Reversals Paleomagnetic records tell us Earth’s magnetic poles have reversed 183 times in the last 83 million years, and at least several hundred times in the past 160 million years.

Detailed explanation-4: -During an excursion or a reversal, the magnetic field is considerably weakened and allows many more cosmic rays to reach the surface of the planet. These energetic particles from space can be damaging to life on Earth if too many reach the surface.

Detailed explanation-5: -By magnetic reversal, or ‘flip’, we mean the process by which the North pole is transformed into a South pole and the South pole becomes a North pole. Interestingly, the magnetic field may sometimes only undergo an ‘excursion’, rather than a reversal.