A map generated by ESA's Swarm array, detailing changes in the Earth's magnetic field - red is strengthening, blue is weakening. Image: ESA/DTU Space
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Get ready for the Earth's magnetic field to flip over

New satellite data has indicated that the Earth's magnetic field is weakening, ahead of a rare - but regular - event.

It's still somewhat surprising to think that plate tectonics has only been an accepted and established for roughly 50 years. That is, our understanding of the structure of atoms was more sophisticated, earlier, than our understanding of the planet we live on. Though, that's maybe unfair; as much as scientists could infer the existence of plate tectonics from, for example, the similarities between the coastlines of Africa and South America, gathering evidence to prove that the Earth has a crust floating on a molten mantle was somewhat difficult. (And it meant that the person credited as the modern theory's originator, Alfred Wegener, was considered a crank for years before the establishment changed its mind.)

After the Second World War, scientists were given the chance to use submarine-detecting devices for peaceful research missions, mapping the ocean floor. In the early 1960s a series of papers were published on the magnetic properties of the undersea world, with some surprising findings - it appeared that some places appeared to have ocean floor with a magnetic field that was the reverse of the Earth's. This chimed with the experience of fisherman living off volcanic islands, who have known for centuries that some patches of ocean can cause the north point of a compass to suddenly switch and point south; and it was consistent with magnetic rocks on land that also seemed to have the "wrong" magnetic polarisation.

Yet what became clear when those patches of irregularity were mapped, across the whole of the Atlantic and Pacific, was that they weren't randomly allocated patches - rather, it became clear that the ocean floor was laid out in long, symmetrical stripes of magnetism, emanating from faults like the Mid-Atlantic Ridge. It was clear that magma was coming up from inside the planet, magnetised with a certain polarity, and then cooling and forming new rock as two tectonic plates moved apart from each other; and that every time the Earth's magnetic field flipped, it reversed the polarisation of the magma that was becoming new sea floor. It was a key discovery in confirming the theory of plate tectonics.

It might be a surprise to hear that the Earth's magnetic field flips over, but it does - every few hundred thousand years, the field weakens, then suddenly (which is relative in this context, on the order of a few hundred years) what was north-facing becomes south-facing, and what was south-facing becomes north-facing. We monitor the Earth's magnetic field with satellites these days, and the European Space Agency's Swarm array has noticed it weakening more significantly than expected:

Measurements made over the past six months confirm the general trend of the field’s weakening, with the most dramatic declines over the Western Hemisphere.

But in other areas, such as the southern Indian Ocean, the magnetic field has strengthened since January.

The latest measurements also confirm the movement of magnetic North towards Siberia.

Rune Floberghagen, the mission manager for Swarm, told Live Science that this new data could mean that a flip is due within the next few hundred years, contrary to earlier estimates of around 2,000 years from now.

We don't yet know whether this is signifying a "proper" flip like the Brunhes–Matuyama reversal of nearly 800,000 years ago, or a more temporary one like the one that occured roughly 40,000 years ago during the last ice age, but which only lasted for slightly more than 400 years. This is in part because we still aren't totally sure why these reverses even happen at all. The poles wobble anyway, and it could be that the molten core of the Earth is a bit like a spinning top, occasionally changing its pattern of movement and falling over; or it could be because of large chunks of mantle nearer the surface "fall" into the centre periodically, causing turbulence that throws things off.

Regardless, the changing of the magnetic field is not a cause for alarm, even if the magnetic field is largely responsible for protecting us all from the worst effects of cosmic radiation. This is because the magnetic field does not entirely disappear - it just weakens. There are some who theorise that these events have been linked with mass extinction events, but the evidence is tenuous at best.

Ian Steadman is a staff science and technology writer at the New Statesman. He is on Twitter as @iansteadman.

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Buying into broadband’s bigger picture

Reliable internet access must be viewed as a basic necessity, writes Russell Haworth, CEO of Nominet.


As we hurtle towards a connected future, in which the internet will underpin most aspects of our daily lives, connectivity will become a necessity and not a luxury. As a society, we need to consider the wider benefits of enabling internet connections for all and ensure no corner of the county is left out of the digital loop.

Currently, despite government incentive schemes and universal service obligations, the rollout of broadband is left largely to the market, which relies on fixed and wireless network operators justifying deployment based on their own business models. The commercial justification for broadband deployment relies on there being sufficient demand and enough people to pay for a broadband subscription. Put flippantly, are there enough people willing to pay for Netflix, or Amazon? However, rather than depending on the broad appeal of consumer services we need to think more holistically about the provision of internet services. If road building decisions followed the same approach, it would equate to only building a road if everyone living in the area bought yearly gym membership for the leisure centre at the end of the new tarmac. The business case is narrow, and overlooks the far-reaching and ultimately more impactful benefits that are available.

Internet is infrastructure as much as roads are, and could easily prove attractive to a wider range of companies investing in digital technology who stand to gain from internet-enabled communities. Health services are one of the most compelling business cases for internet connectivity, especially in remote, rural communities that are often in the “final five per cent” or suffering with below average internet speeds. Super-fast broadband, defined as 30 Mbps, is now available to 89 per cent of UK homes, but only 59 per cent of rural dwellings can access these speeds.

We mustn’t assume this is a minority; rural areas make up 85 per cent of English land and almost ten million people (almost a fifth of the population) live in rural communities. This figure is rising, and ageing ‒ on average, 23.5 per cent of the rural population is over 65 compared to 16.3 per cent in urban areas ‒ and this presents complicated healthcare challenges for a NHS already struggling to meet demand. It goes without saying that accessibility is an issue: only 80 per cent of rural residents live within 4km of a GP’s surgery compared to 98 per cent of the urban population.

While the NHS may not have the resources to build more surgeries and hospitals, robust broadband connections in these areas would enable them to roll out telehealth options and empower their patients with healthcare monitoring apps and diagnostic tools. This would lower demand on face-to-face services and could improve the health of people in remote areas; a compelling business case for broadband.

We can’t afford to rely on “one business case to rule them all” when it comes to internet connectivity – the needs run far beyond Netflix and Spotify, and the long-term, economic and social benefits are vast. It’s time to shift our thinking, considering internet connectivity as essential infrastructure and invest in it accordingly, especially when it comes to the needs of the remote, rural areas of the country.

Russell Haworth joined Nominet as CEO in 2015. He leads the organisation as it develops its core registry business, explores the potential of new technologies in the global internet sector, and delivers on its commitment to ensuring the internet is a force for good.

This article was taken from a New Statesman roundtable supplement "The Internet as Infrastructure: Why rural connectivity is crucial to the UK’s success"

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