The Earth's magnetic field is experiencing something strange. It has been gradually weakening and shifting over the past 200 years its magnetic north pole (where the compass points, but not to be confused or confused with the geographical north pole) from Canada's Arctic towards Siberia. However, the slow shift south has increased to speeds of up to 30 miles per annum in recent decades. Are we on the verge of a geomagnetic reverse, where the magnetic north-south poles swap positions?
The convection of molten steel in the planet's core is what generates Earth's magnetic field. It lies approximately 1,800 miles below our feet. The superheated liquid produces electric currents, which in turn create electromagnetic fields. Although the mechanisms that cause pole reversal are not well understood, computer simulations of the dynamics of planets show that they occur spontaneously. This observation is supported by the Sun's magnetic field which reverses about every 11 years.
Our magnetic field was created at least 4 billion year ago. Since then, Earth's magnetic poles has been reversed numerous times. The magnetic field has changed ten times in the past 2.6 million years. Some scientists think we're due for another switch, as the most recent was 780,000 years ago. However, reversals can't be predicted and they are definitely not regular.
Magnetic Fields Mapping
Volcanic rocks are used by researchers to map the history of Earth's magnetic field. The magnetic field magnetizes iron in lava that cools. These rocks can be examined and radiometric dating techniques used to reconstruct the history of magnetism in the past.
Scientists look at the magnetic properties archaeological artifacts to track recent magnetic changes. Our ancestors used iron to heat an old hearth or kiln, and it would then align its magnetism with the Earth's magnetic field after cooling. This is called the Curie point. Some floor segments from an Iron Age Jerusalem building have been included in studies. This Iron Age building was destroyed by the Babylonian army in 586 B.C.
It is not easy to measure these archeological artifacts. One reason is that the ancient objects' magnetism is too weak to allow a compass needle to move. Multiple magnetic patterns can be created if objects are heated and cooled multiple times. Their reliability depends on whether the objects remain in the same place that they were heated.
Despite these difficulties researchers have successfully mapped the modern changes in the magnet field under western Europe and the Middle East.
There are so many things to love about turtles and salmon and whales!
Scientists aren't able to predict the exact consequences of a reversal, but the evidence from other reversals is not clear. However, they could be severe. Many animals, for example, use the Earth's magnetic field to navigate during migration.
The juvenile loggerhead turtles, which are found in underground nests along Florida's beaches, travel to the Atlantic Ocean and sometimes traverse it completely. After many years, they return home to the Florida beaches where they were born. This featureless journey of 9,000 miles is navigated by them using the strength and direction to the magnetic field. A reversal in the magnetic field could seriously disrupt the lives of salmon, whales and birds, as well as other animals that use Earth's magnetism for navigation.
Earth is also constantly being bombarded by charged particles from the Sun and cosmic radiations, mostly protons from deep space. The magnetic field is less effective in shielding us against these particles during the time leading to a reversal. Some geologists have noted that mass extinctions are associated with these time periods. However, humans and our ancestors have lived on Earth for many million years. There have been many reversals over that period, but there is no apparent correlation with human development.
Tech: A tumultuous time
Although the direct impact on humanity could be minimal, it is not impossible for technology to have an adverse effect. Artificial satellites are used for communication, including weather forecasting, navigation, and television broadcasting. These satellites can be severely disrupted by the collision of cosmic rays or solar wind with electronic circuits if they are not protected by a magnetic field. A weak magnetic field in South Atlantic Ocean is known as the South Atlantic Anomaly. This could already negatively affect satellites. It could also be an indicator of what's to come.
Recent geological research has suggested that the anomaly could be due to geological factors. Although it is believed that our moon formed when Earth was struck by Theia 4.5billion years ago, the remains of Theia are not known. Now, it appears that Theia's remains may be under our feet.
Two huge volumes of rock are deep beneath the Earth. Each one is millions of times bigger than Mount Everest and expanding, and each one is denser and more hotter than the rest. Scientists believe that these rock masses may be Theia's missing remains. They interfere with the convection and formation of the weak magnetic field in South Atlantic.
However, how long it takes for the magnetic reversal to reverse will determine the severity of the situation. It is possible that humans, as well as migratory animals, can adapt if the magnetic reversal takes many thousands of years to complete. We still have much to learn about the deep-rooted changes taking place on our planet.
