In Hollywood's The Core, the core of the earth suddenly stops spinning, causing a magnetic field to collapse. The result: Deadly microwaves lead the Golden Gate Bridge on San Francisco Island and Colosseum in Rome.
According to Justin Revenaugh, the Seinologist at the University of Minnesota, "almost everything is mistaken in the film". While it is true that the Earth's magnetic field protects the planet from deadly and destructive solar radiation – without it, the sun's winds can dry up the Earth's oceans and take away the planet's atmosphere – but the planet's magnetic field is not static.
The Earth's North Magnetic Pole (which does not correspond to the geographical northern direction) in the last century has led scientists to some sort of march. It moves north every year at an average of 50 kilometers.
This movement made the World Magnetic Model (WMM) inaccurate. The model tracks the field and informs the compasses, the GPS and navigation systems of the smartphone in planes and ships. With the next planned WMM update not scheduled before 2020, US military troops requested an earlier update to include accelerated magnetic north movements.
The authors of the new study have now gained insight into why the magnetic north pole could move and are now learning how to predict these changes.
Track movements in the core of the earth
The Earth's magnetic field passes through a swirling fluid of nickel and iron on the outer part of the planet, about 2,900 kilometers below the surface. Strengthened by the magnetic poles of the north and south (which tend to change and even change every million years), the area increases and decreases depending on what is happening in the core.
Periodic and sometimes accidental changes in the distribution of this turbulent liquid metal may result in magnetic field characteristics. If you think of a magnetic field as a series of rubber bands that pass through the magnetic poles and the core of the Earth, the changes in the nucleus will take place at different locations on different rubber bands.
These geomagnetic fluctuations affect the migration of the northern magnetic poles and may even cause its drift away.
Forecasting these changes in magnetic fields has been a problem so far. In the new study, the geophysists Julien Aubert and Christopher Finlay tried to simulate the physical conditions of the Earth's nucleus by calculating supercomputers for four million hours.
The researchers knew that the movement of heat from within the planet could affect the magnetic field about ten kilometers a year. However, they found that the kernel sometimes had liquid iron pockets that were much warmer and lighter than the surrounding fluid. If the difference between these hot, less dense fluids and their cooler, denser counterparts is large enough, the warm liquid can rise rapidly.
This rapid movement causes magnetic waves that move to the nucleus surface, causing geomagnetic shocks.
"Imagine these waves as the vibrating strings of a musical instrument," said Aubert.
Magnetic North is important for navigation models
Magnetic Northern Control is essential for European and US military personnel, as their navigation systems rely on WMM. Businesses and smart phone GPS applications also help pilots and users identify their locations and navigate accordingly.
That is why the British Geological Survey and the National Oceanic and Atmospheric Administration every five years update WMM. The US military proxy early update was completed on February 4th.
But even with these regular updates, geomagnetic shocks make it difficult to maintain the model accurately, said Aubert.
The new model of his research team could solve this problem by helping to predict how the Earth's magnetic field could develop.
"We expect that in the coming years it will be possible to get past shocks and predict future improvements," said Auberts.
Could the magnetic field collapse?
Earth's magnetic field protects the atmosphere that "does much to keep the sun's rays" as Revenaugh pointed out. If we lost our magnetic field, we would eventually lose the atmosphere.
However, according to Revenaugh, this is very unlikely because the Earth's core never spins.
Even if the field collapsed, the devastating effect of the film "Core" – people with pacemakers who would die and escape the storms – would not be the result.
Revenaugh is likely to say that magnetic poles would return as it was 780,000 years ago.
If such coups take place (there were several in Earth's history), the magnetic field fell to about 30 percent of its full force, he said.
Read also: Researchers have successfully acquired nuclear fusion – an object that is small enough to keep at home
Although this is a long-term scenario, Revenaugh added that it is still important to improve the scientific understanding of magnetic fields today. "The better we can model it, the better we understand what it is," he said.
Translated from German.