Pole shift what does it mean

Satellites and crewed space missions will need extra shielding that we'll have to provide ourselves. Without it, intense cosmic and solar radiation will fry circuit boards and increase the risk of cancer in astronauts. Our modern way of life could cease to exist.

We know this because we're already seeing a glimpse of this in an area called the South Atlantic Anomaly. Turns out, the direction of a portion of the magnetic field deep beneath this area has already flipped! And scientists say that's one reason why the field has been steadily weakening since As a result, the Hubble Space Telescope and other satellites often shut down their sensitive electronics as they pass over the area.

And astronauts on the International Space Station reported seeing a higher number of bright flashes of light in their vision, thought to be caused by high-energy cosmic rays that the weaker field can't hold back. Since experts started measuring the Anomaly a few decades ago, it has grown in size and now covers a fifth This is so extreme that it could be a sign we're on the brink of a polar flip, or we may already be in the midst of one!

Mitchell: They don't know. The last time the poles reversed was , years ago so it's not like we have a record for this. Mitchell: In the past 65 million years since the last mass extinction there have been reversals roughly every , years. So what is a geomagnetic reversal? Share Tweet Email. Why it's so hard to treat pain in infants. This wild African cat has adapted to life in a big city. Animals Wild Cities This wild African cat has adapted to life in a big city Caracals have learned to hunt around the urban edges of Cape Town, though the predator faces many threats, such as getting hit by cars.

India bets its energy future on solar—in ways both small and big. Environment Planet Possible India bets its energy future on solar—in ways both small and big Grassroots efforts are bringing solar panels to rural villages without electricity, while massive solar arrays are being built across the country.

Go Further. Animals Wild Cities This wild African cat has adapted to life in a big city. Animals This frog mysteriously re-evolved a full set of teeth. Animals Wild Cities Wild parakeets have taken a liking to London. Animals Wild Cities Morocco has 3 million stray dogs. Meet the people trying to help. The weakened magnetic field allowed more ionising radiation from solar flares and cosmic rays from space to reach Earth. This would have caused extreme weather conditions, including lightning, high temperatures and lots of sunlight — which may have been difficult for organisms to adapt to.

Megafauna across Australia and Tasmania — prehistoric giant mammals that existed in the Late Pleistocene — and Neanderthals in Europe went extinct around the same time as the magnetic pole reversal, 42, years ago. The north pole has been moving spasmodically over the past century, drifting around a kilometre per year, says Cooper.

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. Interestingly, the magnetic field may sometimes only undergo an 'excursion', rather than a reversal.

Here, it suffers a large decrease in its overall strength, that is, the force that moves the compass needle. 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.

How often do reversals occur? As a matter of geological record, the Earth's magnetic field has undergone numerous reversals of polarity. We can see this in the magnetic patterns found in volcanic rocks, especially those recovered from the ocean floors. In the last 10 million years, there have been, on average, 4 or 5 reversals per million years. At other times in Earth's history, for example during the Cretaceous era, there have been much longer periods when no reversals occurred.

Reversals are not predictable and are certainly not periodic in nature. Hence we can only speak about the average reversal interval. Measurements have been made of the Earth's magnetic field more or less continuously since about Some measurements even go back to the s, for example at Greenwich in London.

If we look at the trend in the strength of the magnetic field over this time for example the so-called 'dipole moment' shown in the graph below we can see a downward trend. Indeed projecting this forward in time would suggest zero dipole moment in about years time.

This is one reason why some people believe the field may be in the early stages of a reversal. We also know from studies of the magnetisation of minerals in ancient clay pots that the Earth's magnetic field was approximately twice as strong in Roman times as it is now. Even so, the current strength of the magnetic field is not particularly low in terms of the range of values it has had over the last 50, years and it is nearly , years since the last reversal.

Also, bearing in mind what we said about 'excursions' above, and knowing what we do about the properties of mathematical models of the magnetic field, it is far from clear we can easily extrapolate to years hence. We have no complete record of the history of any reversal, so any claims we can make are mostly on the basis of mathematical models of the field behaviour and partly on limited evidence from rocks that retain an imprint of the ancient magnetic field present when they were formed.

For example, the mathematical simulations seem to suggest that a full reversal may take about one to several thousand years to complete. This is fast by geological standards but slow on a human time scale. As above, we have limited evidence from geological measurements about the patterns of change in the magnetic field during a reversal.

We might expect to see, based on models of the field run on supercomputers, a far more complicated field pattern at the Earth's surface, with perhaps more than one North and South pole at any given time.