Earth's Magnetic Poles Won't Flip For Thousands Of Years, Study
The intensity of the earth's magnetic field is still double the long-term average expected over the last 5 million years. Hence, a shift of a geomagnetic pole is not likely to happen for another millennium.
Currently, the earth's magnetic field is comparitively strong. That is why a reversal has not happened for such a long period. It is mainly because strong fields are less susceptible to reversals, according to Science News.
Scientists examined the paleointensity information of prehistoric lava flows near the equator and compared them with other flows in the proximity of the South Pole, according to the Daily Mail.
With the cooling of lava, it is known that its iron minerals are in sync with the Earth's magnetic field. Hence scientists were able to use information from the lava to measure the direction and intensity of the magnetic field at the time when it had been formed. Thus, they compared 27 lava samples from the equator to 38 from the South Pole, stretching over 5 million years.
"Sometimes you won't have a flip for about 40 million years; other times there will be 10 flips in 1 million years," said Huapei Wang, lead author of the study. "On average, the duration between two flips is a few hundred thousand years. The last flip was around 780,000 years ago, so we are actually overdue for a flip."
He added, "What I can say is, if you keep a constant present-day decrease rate, it will take another 1,000 years for the field to drop to its long-term average, From there, the field intensity may go up again. There's really no way to predict what will happen after that, given the random nature of the magnetohydrodynamic process of the geodynamo."