Science

True north, magnetic north and grid north to combine over Britain for the first time in history

The three ‘norths’ will converge over Britain for the first time in history this month and will remain over the country for the next three and a half years.

What this means is that true north, magnetic north and north of the grid will all align, according to the national mapping service Ordnance Survey.

True north is the direction along the Earth’s surface that ends at the North Pole, while magnetic north points where the planet’s magnetic field goes down.

Grid North is the direction of the grid lines on maps, which usually point toward or near the North Pole.

The three northern lands will make landfall in the village of Langton Matravers, just west of Swanage, in early November before slowly moving inland.

dr. Susan Macmillan, of the British Geological Survey, said: ‘This is a once-in-a-lifetime experience.

“Due to the unpredictability of the magnetic field on long timescales, it is not possible to say when the alignment of the three norths will occur again.”

The Red Line Shows Magnetic North, While The Blue 'Special Line' Is True North And The Grid North Line Are Perfectly Aligned.  The Three Northern Lands Will Make Landfall For The First Time In Early November At The Village Of Langton Matravers, Just West Of Swanage (Pictured).  Magnetic North Will Move East Over Time

The red line shows magnetic north, while the blue ‘special line’ is true north and the grid north line are perfectly aligned. The three northern lands will make landfall for the first time in early November at the village of Langton Matravers, just west of Swanage (pictured). Magnetic north will move east over time

True North Is The Direction Along The Earth'S Surface That Ends At The North Pole, While Magnetic North Points Where The Planet'S Magnetic Field Goes Down.  Grid North Is The Direction Of The Grid Lines On Maps, Which Usually Point To Or Near The North Pole

True north is the direction along the Earth’s surface that ends at the North Pole, while magnetic north points where the planet’s magnetic field goes down. Grid North is the direction of the grid lines on maps, which usually point to or near the North Pole

At Some Point This Week, The Triple Alignment Will Traverse Langton Matravers Before Heading North To Poole By Christmas And Then Further Inland.

At some point this week, the triple alignment will traverse Langton Matravers before heading north to Poole by Christmas and then further inland.

WHAT IS THE DIFFERENCE BETWEEN TRUE NORTH, MAGNETIC NORTH AND JUST NORTH?

true north is the direction of the longitudinal lines along the Earth’s surface that end at the North Pole. It is determined by the rotation of the planet.

Magnetic North is the direction of the compass and the location where the Earth’s magnetic field points vertically downwards. The direction of magnetic north is constantly changing due to natural changes in the magnetic field.

Grid north is the direction in which the grid lines on a map point ie. the top of the card.

Mark Greaves, Earth Measurement Expert at Ordnance Survey, said: ‘It’s no exaggeration to say that this is a one-off event that has never happened before.

“Magnetic north moves slowly, so it will probably take several hundred years for this alignment to reappear.

“This triple alignment is an interesting quirk of our national mapping and the natural geophysical processes driving the changing magnetic field.”

The north of the grid is represented on Ordnance Survey maps by the vertical blue grid lines and has been since the current mapping system was introduced in 1936.

On most maps, true north curves away from the grid’s north, as the former reflects the curved surface of the Earth.

However, one specific grid north line corresponds to true north.

This “special line” is the meridian of 2° W longitude, and magnetic north will coincide along this line starting this week.

This is because the direction of magnetic north is constantly moving due to natural changes in the Earth’s magnetic field.

The magnetic north line has always been west of the grid north in Britain, but in 2014 it started moving slowly across the country to the east.

It has now moved to the other side of grid north and is approaching the ‘special line’ where grid north and true north align.

This 'Special Line' Where True North And North Of The Grid Align Is The 2°W Longitude Meridian (Pictured), And Along This Line Magnetic North Will Coincide From This Week

This ‘special line’ where true north and north of the grid align is the 2°W longitude meridian (pictured), and along this line magnetic north will coincide from this week

Magnetic North Is The Direction Of The Compass And The Location Where The Earth'S Magnetic Field Points Vertically Downwards.  The Direction Of Magnetic North Is Constantly Changing Due To Natural Changes In The Magnetic Field

Magnetic north is the direction of the compass and the location where the Earth’s magnetic field points vertically downwards. The direction of magnetic north is constantly changing due to natural changes in the magnetic field

At some point this week, the triple alignment will traverse Langton Matravers before heading north to Poole by Christmas.

They will then meet again in Chippenham and Birmingham, reaching the Hebden Bridge in Yorkshire in August 2024.

It will pass through the Pennines before leaving the English coast at Berwick-Upon-Tweed a year later, in August 2025.

The alignment won’t make landfall again at Drums, just south of Newburgh in Scotland, around May 2026.

After passing Mintlaw, the last stop in Scotland and the landmass of Great Britain is Fraserburgh, which it will reach in July 2026.

According to Mr. Greaves, this event should make no difference to navigators, as the same rules apply when using a map to find your way.

“They will always have to account for the variation between the magnetic north of a compass and the grid or true north on a map,” he said.

The Triple Alignment Will Reach The Hebden Bridge In Yorkshire In August 2024.  Pictured: The 'Special Line' Passing Through Hebden Bridge

The triple alignment will reach the Hebden Bridge in Yorkshire in August 2024. Pictured: The ‘special line’ passing through Hebden Bridge

The Earth’s magnetic field, and thus magnetic north, is largely generated by the superheated, swirling liquid iron that forms the outer core of 3,000 kilometers below our feet.

As heat escapes from the inner core, the iron moves in convection currents, generating powerful electrical currents.

The rotation of the Earth on its axis causes these electric currents to form a magnetic field that extends around the planet and extends into space.

Ordnance Survey says these location predictions are likely to shift by a few months due to changes in iron flow in the outer core.

This is because they will affect magnetic field observations conducted by the British Geological Survey (BGS) at 40 sites across the UK.

These measurements allow scientists to create high-resolution maps and make accurate predictions of the changing angle of declination.

Climate change has shifted Earth’s poles, study shows

Rising global temperatures caused by humans are responsible for shifts in Earth’s magnetic field, a new study claims.

The Earth’s magnetic north and south poles are in constant motion — a phenomenon known as “polar wandering.”

But Chinese researchers reveal that climate change melting glaciers caused shifts in the Earth’s mass in the mid-1990s.

This change in mass caused the movement of the magnetic poles to turn and accelerate eastward, they say.

Read more here

Shifts In The Geographic Location Of The Earth'S North And South Poles Are Called Polar Drift Or True Polar Drift.  This Image Shows The Change In Position Of The Magnetic North Pole

Shifts in the geographic location of the Earth’s north and south poles are called polar drift or true polar drift. This image shows the change in position of the magnetic north pole

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