There are some facts in this world that are thought to be fixed forever. Some earthly things that we think are never going to change. For example, north is always going to be north, right? Well, believe it or not, there are some scientists who are pretty sure that that is not the case. And the results for life on our planet might well be disastrous.
You’ve probably heard about the Earth’s magnetic field, but what you might not realize is just how important it is. What’s more, there’s a good chance that you are not quite sure where it comes from, either. Both of those things are important to understand before we get to grips with the cataclysm that some researchers think could be on the horizon.
The Earth’s magnetic field stretches out from the center of the planet into space. You can imagine it like the scope of a magnet which has somehow been placed in the middle of the world. And it is hugely important for the development, and sustainability, of life as we know it.
You see, the magnetic field protects us from what is known as the solar wind. This wind, which is actually a flood of particles, comes from the corona – or aura – of the Sun. It is a blast of electrons, protons and alpha particles that is sometimes referred to as plasma. And without the magnetic field surrounding the Earth, this phenomenon would wreak havoc.
That’s for the simple reason that the magnetic field protects the ozone layer from the worst of the solar wind. You see, without the ozone layer the planet would be flooded by ultraviolet radiation from the Sun. Scientists know this for a fact because one of our closest cosmological neighbors suffered the same fate in the dim and distant past.
About four billion years ago, it is believed, Mars’ magnetic field stopped working properly. This made the planet incredibly susceptible to the ravages of the solar wind. In turn, the wind is likely to have stripped the atmosphere from Mars, leaving it the “dead planet” that we know now. But why did that happen?
Earth’s magnetic field is actually generated in the center of the planet. The best theory is that a self-sustaining internal loop, known as a geodynamo, creates the field that generates outwards and shields us from the harmful emanations of the Sun. And this geodynamo is all thanks to the molten core underneath our feet and the materials it is made up of.
To put it simply, there is an awful lot of metal in the center of the Earth. A vast amount of iron lies in the molten core. It is mostly liquid and surrounds a solid inner core. Because the iron is conductive, the movement of this liquid metal creates electricity. This power creates magnetism, and vice versa, and so the field is sustained by the motion of the fluid.
The simple reason that Mars lost its magnetic field is that the movement at the red planet’s core ceased. No movement meant no electricity. No electricity led to no magnetic field. And while it is highly unlikely that the same fate is going to befall the Earth anytime soon, nonetheless there is something else scientists are incredibly worried about. Furthermore, it turns out that this concern is quite justified, as there is historical precedence for it.
At some point, about 800,000 years ago, something strange happened to the planet. Scientists know this for certain because it is there in the Earth’s geological records. In the early part of the last century, some volcanic rocks were studied in the Far East. They were magnetized, much as the geologist researchers had expected. But for some reason the rocks were magnetized in the opposite direction to the way they should have been owing to the magnetic field.
However, it took around 50 years of research, and a better understanding of the magnetic field, to realize the enormity of what had been discovered. Further investigation showed that these rocks were not anomalies. In fact, there were patterns in the crust of the planet that showed quite conclusively that sometimes the Earth’s magnetic field changes completely. But in what sense?
This brings us back to our opening assumption. You see, “north,” it turns out, is not always north. Or, more accurately, the planet’s magnetic north is not always in the same direction. At times in Earth’s history, the polarity of the magnetic field has completely reversed. In other words, you might be heading geographically north, but any compass would be telling you that you were actually traveling south.
Now this might sound confusing and annoying – but there are more far-reaching consequences than simply having to buy a new compass. Canadian Alanna Mitchell is an award-winning science author and journalist. And she believes that a reversal in polarity in the coming years could well have some pretty devastating consequences for living things that currently rely on the magnetic field – including humanity.
For example, a lot of animals use the magnetic field to navigate around the world. Speaking to National Geographic magazine in February, 2018, Mitchell spelled out some of the possible ecological problems that a reverse in polarity might create. “Some turtles need to go back to the very same bay in Australia in order to lay their eggs,” she said. “The concern is that they won’t be able to find that beach if they can’t navigate by the magnetic field, and they may end up going somewhere else.”
Yet there is something else that could cause terrible problems for human life. If the poles do flip, then there is a very good chance that the magnetic field could actually weaken. And while the field is in constant flux, if it drops in strength for a considerable amount of time, then the planet is going to be incredibly vulnerable to the radiation that the Sun is spewing out. But is that something we should be lying in bed worrying about?
Mitchell has spoken to scientists who are convinced that it absolutely justifies some sleepless nights. She told National Geographic, “One scientist I spoke to, Daniel Baker, of the University of Colorado, who is an expert in radiation from the Sun and how that affects our planet, says there’s no question in his mind that parts of the planet will become uninhabitable.”
If the Earth’s magnetic field is substantially weakened, then there is the chance that cosmic particles – which can cause damage to humans – will impact the planet. But there is a catch: it is almost impossible to predict where the damaging rays will strike. In other words, we’re totally in the dark when it comes to the harm the Sun might do to us.
Then there is the problem of what would happen if a large solar storm struck the planet when its magnetic field was weakened. Projections undertaken after a near miss in 2012 present a pretty bleak picture for the Earth. According to Mitchell “forensic analysis suggests that we would have been sent back to the Victorian age in terms of our electrical systems had that happened.” The cost could have been upwards of a staggering $40 billion per day to the U.S. economy alone.
But it is not quite time to start stockpiling canned goods and bottled water just yet. Indeed, while the effects of a polarization of the magnetic field could be enormous, they could also take a long time to transpire. Most flips in the field take thousands of years to happen, which gives us plenty of time to get ready to combat any of the problems that are likely to be thrown up.
And if humanity is comfortable in being well prepared in advance, then there is going to be an upside to the weakened magnetic field as well. The auroras, which occur when the solar wind interacts with the field, will be visible at less extreme latitudes. These fantastic phenomena would, then, make the sky at night a lot more beautiful for an awful lot more people.