The reversals take place when iron molecules in Earth’s spinning outer core start going in the opposite direction as other iron molecules around them. As their numbers grow, these molecules offset the magnetic field in Earth’s core.

The data showed that the position of the north magnetic pole is determined largely by a balance, or tug-of-war, between two large lobes of negative flux at the boundary between Earth’s core and mantle under Canada.

The inclination of the Earth’s field is 90° (downwards) at the North Magnetic Pole and -90° (upwards) at the South Magnetic Pole. The two poles wander independently of each other and are not directly opposite each other on the globe.

A growing dent in Earth’s magnetic field could wreak havoc on satellites and the space station, NASA says. Earth’s magnetic field protects the planet from deadly solar radiation, but it has weakened over the last few centuries.

The forces in the core and the tilt of the magnetic axis together produce the anomaly, the area of weaker magnetism – allowing charged particles trapped in Earth’s magnetic field to dip closer to the surface.

The Earth’s magnetic field is weakening and scientists don’t know why. A weaker magnetic field will make the planet more susceptible to solar radiation and put space equipment at risk.

A weaker field enables more charged particles from deadly solar winds to make their way through the Earth’s protective shield. If spacecraft and satellites in low-Earth orbit (within 1,200 miles of the planet’s surface) get bombarded with these particles, they can go haywire.

But what would happen if Earth’s magnetic field disappeared tomorrow? A larger number of charged solar particles would bombard the planet, putting power grids and satellites on the fritz and increasing human exposure to higher levels of cancer-causing ultraviolet radiation.

42,000 years ago

Every several hundred thousand years or so, Earth’s magnetic field dramatically shifts and reverses its polarity. Geologist found that the most recent field reversal, some 770,000 years ago, took at least 22,000 years to complete.

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. During an excursion the field does not reverse, but later regenerates itself with the same polarity, that is, North remains North and South remains South.

From the southern hemisphere, magnetic field lines curve around the globe and re-enter the planet in the northern hemisphere. The angle between the field lines and the Earth changes with latitude, so an animal migrating northwards from the equator encounters steadily steeper inclination angles on its route.

A study published today offers some of the best evidence yet that humans, like many other creatures, can sense Earth’s magnetic field. A variety of species—bacteria, snails, frogs, lobsters—seem to detect Earth’s magnetic field, and some animals, such as migratory birds, rely on it for navigation.

The ability to detect and orient using the magnetic field is fairly common in the animal kingdom overall, according to Keller. Scientists have observed that type of behavior in bacteria, algae, mud snails, lobsters, eels, stingrays, honey bees, mole rats, newts, birds, fish like tuna and salmon, dolphins, and whales.

Life on Earth initially developed and continues to be sustained under the protection of this magnetic environment. The magnetosphere shields our home planet from solar and cosmic particle radiation, as well as erosion of the atmosphere by the solar wind – the constant flow of charged particles streaming off the sun.

The magnetic field of the Earth plays a very important role in our lives, it protects us from the solar winds. These are currents of particles charged of energy emanated from the sun which emit radiation. The magnetosphere deflects the dangerous ultraviolet rays of the sun, keeping us safe from any risk.

The Earth’s magnetic field does not directly affect human health. Humans evolved to live on this planet. High-altitude pilots and astronauts can experience higher levels of radiation during magnetic storms, but the hazard is due to the radiation, not the magnetic field itself.