Scientists explain worrying things that would happen if Earth’s magnetic field flipped with NASA on alert over ‘dent’

There are a million and one reasons that make Earth habitable for humans and every other creature around us. But central to that is one major thing: the planet's magnetic field.

A protective blanket surrounding Earth, it does the business and more when it comes to protecting life from nasty storms heading towards the planet.

Most of that comes from the Sun in the form of solar wind. If we didn't have the magnetic field, we'd suffer a fate similar to what Mars looks like nowadays. Cold, barren, and ultimately all the telltale signs of a planet that used to have life.

It is this magnetic field that has recently got NASA scientists on high alert following the identification of a 'dent' in the protective cover; an area known as the South Atlantic Anomaly (SAA).

Central to the planet's magnetic field is the magnetic poles, which are two spots at the top and bottom of the planet that act as a continuous loop through which invisible magnetic field lines travel in an ongoing loop. The video below provides a visual explanation:

Well, what happens when it flips? Would humanity be okay if this happened during our time on the planet?

This is a phenomenon that happens, on average, every hundred thousand years or so in Earth's lifecycle.

Flipping the magnetic field

Since the beginning of Earth as we know it, scientists reckon there has been at least 183 occasions where the planet's magnetic poles have flipped.

When they flip is random, with the event happening between 10,000 years and 50 million years. Talk about a broad timescale.

The last time the poles flipped was 780,000 years ago in an event called the Brunhes - Matuyama reversal.

Earth is surrounded by a magnetic field (Getty Stock Images)

Will it flip again soon?

The South Atlantic Anomaly has got some worried we're heading to this point again.

First discovered in 1958, the SAA is an area of the magnetic field that is significantly weaker than the rest of it around Earth.

And stretching from South America across the southern Atlantic Ocean to Africa, it's a big area of the planet. Effectively, it means this part of the planet has less protection from cosmic nasties than the rest of it (that goes for satellites flying through over this patch in orbit, too).

According to one study from 2018, the next flip isn't happening any time soon.

"There has been speculation that we are about to experience a magnetic polar reversal or excursion," Richard Holme from the University of Liverpool said.

"However, by studying the two most recent excursion events [from 31,400 and 34,000 years ago], we show that neither bear resemblance to current changes in the geomagnetic field and therefore it is probably unlikely that such an event is about to happen.

"Our research suggests instead that the current weakened field will recover without such an extreme event, and therefore is unlikely to reverse."

Could north become south? (Getty Stock Images)

What would happen if the magnetic field flipped?

It would not be very good news at all, with life as we know it changing in a number of ways.

Jean-Pierre Valet, a researcher on geomagnetic reversals at the Institute of Earth Physics of Paris, said: "The most dramatic changes that occur when the poles reverse is a very large decrease of the total field intensity."

In other words, we would experience a massive drop off in overall protection from the magnetic field.

And given that the flip takes between 1,000 and 10,000 years to fully reverse, it's a time period that would see significant loss for a long time.

Earth's magnetic field (Getty Stock Images / NASA)

"It's not a sudden flip, but a slow process, during which the field strength becomes weak, very probably the field becomes more complex and might show more than two poles for a while, and then builds up in strength and aligns in the opposite direction," said Monika Korte, scientific director of the Niemegk Geomagnetic Observatory at GFZ Potsdam in Germany.

It is this 1,000 to 10,000-year window in which humans would be at their most vulnerable, potentially more open to the effects of solar storms which could now hurt us on the planet in ways such as an increase skin cancer cases.

As for it being an extinction level event? Scientists aren't sure, with many unconvinced. Korte explained: "Even if the field becomes very weak, at the Earth's surface we are shielded from radiation by the atmosphere. Similarly as we cannot see or feel the presence of the geomagnetic field now, we most likely would not notice any significant change from a reversal."

But while we might not go extinct from the dangers of space, our kit would be in huge trouble. Satellites would be knocked out, GPS offline, and power outages across the globe.

Such events would potentially cripple life on Earth, disrupting food production, medical care, global transport, and Wi-Fi networks. The only saving grace is that this is a gradual change, giving humanity time to react as potential issues arise.