Showing posts with label shifting of earth's magnetic field. Show all posts
Showing posts with label shifting of earth's magnetic field. Show all posts

Saturday, February 23, 2019

Science Mystery: Magnetic North is on the Move

Science Mystery: Magnetic North is on the Move

World Magnetic Model

The northern magnetic pole of the Earth is said to be shifting towards Siberia away from the Canadian Artic. This shifting has compelled the scientists of NCEI to update the mid-cycle of World Magnetic Model– WMM. An official new magnetic model of the world is used for its navigation system which has been moving at a rate of about 50 to 60 kilometres per year, according to The Guardian. Essential to warrant precise navigation towards the North Pole, the World Magnetic Model update has moved ahead from a planned 2020 release owing to the present speed of this movement. The north magnetic pole is said to be on the move.

Instead of moving around as it had for ages, the pole had picked up considerable speed and is moving quickly towards Siberia. Funded by the US and UK military, usually an updated version of the World Magnetic Model is released once in five years wherein the last had been released in 2015. Release of the next version is scheduled to be towards the end of 2019.

The military utilises the World Magnetic Model for undersea and aircraft navigation, parachute positioning etc. The other governmental businesses like NASA, the Federal Aviation Administration, U.S. Forest Service and others tend to utilise this technology for the purpose of surveying and mapping, satellite/antenna tracing and air traffic management.

Unexpected Variations in Artic Area


Scientists have released an updated model to precisely present the changes of the magnetic field between 2015 and the present time, owing to the unexpected variations in the Artic area. This unexpected update before the official release of next year’s World Magnetic Model 2020, would warrant innocuous navigation for military application, search, rescue operation together with commercial airlines and others functioning around the North Pole.

 A geophysicist at the British Geological Survey in Edinburgh, Ciaran Beggan commented, `We know from old ship’s logs that in the past 400 years, the north magnetic pole has hung around northern Canada. Till the 1900s, it had moved perhaps tens of kilometres, back and forth. However in the past 50 years it had started to move north and in the past 30 years it started to accelerate away. It went from moving at about five to ten km a year to 50 to 60 km a year currently. It’s now moving rapidly towards Siberia’.

Affecting Navigation 


The World Magnetic Model tends to trail the situations of the magnetic poles of the Earth.Beggan had mentioned that they realised that mainly up around the north magnetic pole, the inaccuracieshad seemed to be great for it to be useful. The drifting pole has the tendency of affecting navigation in the Arctic. Should the GPS fail, the pilots on planes and ships will fall back on compass navigation and would require an updated map for their on-board computers.

The US military, at high altitudes, have named airport runways after their direction with regards to magnetic north and tends to change them when the pole moves. The recent movement of the pole is believed to be due to the formation of a narrow stream which is like the jet stream in the atmosphere, in the liquid outer core of the Earth. The iron-nickel core is said to be so hot that it tends to flow like water – 3,000 km below the surface creating the magnetic field and moving it around the planet.

Weakening of Magnetic Field


Beggan had stated that the north magnetic pole has been caught in this jet and is pushing it rapidly towards Siberia. The south magnetic pole seems to be moving much slower than the north due to the liquid outer core moving differently in the southern hemisphere. The magnetic field of the Earth is growing gradually weaker which is leading the scientist to contemplate that it will ultimately lead the north and the south poles to change places like a bar magnet toppling over.

From the traces of rocks, researchers are aware that this had taken place earlier though not in the past 780,000 years. Daniel Lathrop, a geophysicist at the University of Maryland stated that `it’s not a question of if it’s going to reverse, the question is when it’s going to reverse and such a flip would not be instantaneous, but would take 1,000 or more years to play out’.

Lathrop is of the belief that the flip would take place sooner than later owing to the weakening of the magnetic field, considering that an area in the south Atlantic had already overturned below the surface of the Earth. According to Beggan the rise and the fall in the strength of the magnetic field’s movement seems to be a part of its natural behaviour.

 He said that in the long term, the movement of the north magnetic field would become noticeable since it tends to affect where aurora, namely the northern lights, can be seen. He further commented that the aurora is focussed around the north magnetic pole in a ring enabling the pole to move and the aurora tends to follow it.

Wednesday, December 16, 2009

THE SHIFTING OF MAGNETIC FIELD OF EARTH

THE SHIFTING OF MAGNETIC FIELD EARTH



It is quite interesting to know the changes in polarity of the earth’s magnetic field.  Suppose the earth’s magnetic field suddenly shifted means what will happen?  The entire radio communication of the world will get jammed, the birds and animals migration will not happen. Interesting, Is not it?  Let us see more about the earth’s magnetic field.

Around 7,80,000 years ago the earth’s magnetic field was reversed exactly 180 degrees.  For the last few decades scientists and geo physicists have known that earth’s magnetic field has shifted several times in the past.  But the exact timing and causes of these magnetic shifts are still not clear to the scientists.

Firstly we have to recollect some basics of the earths crust. The earth behaves like a giant magnet and its magnetic poles are not strictly aligned with rotational axis of the earth they are inclined about 11 degree and hence the magnetic poles are away form the geographical poles.

 The magnetic effect is caused by the electric current produced by the moving molten matter in the earth’s core.  This is like a dynamo hence the scientists call this theory as Dynamo theory.

Since the changes occurred a long ago it is very tough to know the shifts in the earth’s magnetic field, but it is unfolded by the rocks that makes up the earth’s crust.  When the rocks were formed the prevailing directions of the magnetic fields are frozen inside them. They are magnetized for a long time.

When the igneous rocks formed by the volcanic eruptions, the magnetic materials   present in the molten magma behaved as a magnetic compass needles and they deposited according to the earth’s magnetic field.  For finding this residual magnetism the scientists uses magnetometers and maps the fluctuations in the magnetic field.


In 1960 the French scientist Bernard Brunches determined the present magnetic epoch was happened 780000 years ago and hence it was named after his name.  What he did is, He discovered a series of lava flows with reversal polarity.  After finding them he record the ages of the events happened, by judging the age of the rocks series and makes it possible to date with greater certainty.  This is the only way of dating the rock series.


This procedure has revealed so many hidden secrets.  The rock series of normal and reverse polarity makes a zebra striped symmetry.  This shows the Ocean floor is spreading which is a proof to the Continental drift theory. When the shifting of magnetic field happens, the magnetic poles prefer certain routes such as north south route through America.

At present the magnetic field is weakening noticeably which is the system for a new shifting of earth’s magnetic field is going to happen.