- Title: Hold onto your compass as true and magnetic north converge
- Date: 6th September 2019
- Summary: GREENWICH, ENGLAND, UK (SEPTEMBER 5, 2019) (REUTERS) PRIME MERIDIAN LINE ON THE GROUND / GEOMAGNETICIST CIARAN BEGGAN HOLDING A MAGNETIC COMPASS MAGNETIC COMPASS BEGGAN TALKING TO SENIOR CURATOR, ROYAL OBSERVATORY, GREENWICH DOCTOR LOUISE DEVOY (SOUNDBITE) (English) DR. CIARAN BEGGAN, BRITISH GEOLOGICAL SURVEY GEOMAGNETICIST SAYING: "We are at the cusp of a quite unusual event where the magnetic field is pointing directly north along the Greenwich meridian here and so if you hold a compass along this line it will point directly toward true north and it's the first time that's happened since 1660. So it's 360 years since this has happened beforehand." BEGGAN AND DEVOY STANDING ON EITHER SIDE OF THE PRIME MERIDIAN (SOUNDBITE) (English) DR. CIARAN BEGGAN, BRITISH GEOLOGICAL SURVEY GEOMAGNETICIST SAYING: "The Earth's magnetic field is actually created by the flow of liquid iron deep in the centre of the Earth and as this iron flows it creates electricity and the electricity also creates magnetism because there is this link between electricity and magnetism. And so what we see on the surface of the Earth is that magnetism leaking out from the outer core and filling up to the Earth out in space and because it's liquid it also flows westward all the time and so the liquid outer core drags the magnetic field with it and that's why the north pole, the magnetic north pole position changes all the time." VARIOUS OF BEGGAN DESCRIBING A DIGITAL COMPASS BEGGAN AND DEVOY TALKING (SOUNDBITE) (English) DR. CIARAN BEGGAN, BRITISH GEOLOGICAL SURVEY GEOMAGNETICIST SAYING: - protects the Earth's atmosphere from solar wind "There's no actual impact of this particular change in time but over periods of say 5 or 10 years the magnetic field will change enough that we have to update all the maps that we use to correct for the difference between true north and magnetic north all the way round the world. So within your smartphone or your satnav navigation system there will generally be a digital compass and it will know the way towards magnetic north and at the British Geological Survey we provide maps to make the correction towards true north. Now if you are stood here today using a compass there is no correction to make and that's what's unique about this place at this point in time." VARIOUS OF DOCTOR LOUISE DEVOY COLLECTING BOOK OF HISTORIC MAGNETIC DEVIATION OBSERVATIONS VARIOUS OF MAGNETIC DEVIATION OBSERVATIONS (SOUNDBITE) (English) DR. LOUISE DEVOY, SENIOR CURATOR, ROYAL OBSERVATORY, GREENWICH SAYING: "It's just interesting because it aligns with this historic meridian. In some ways it's a human construct. The meridian was chosen here but it could have been anywhere else. So it's just a nice coincidence really." DEVOY DESCRIBING 19TH CENTURY MAGNETIC MEASURING DEVICES IN A CABINET (SOUNDBITE) (English) DR. LOUISE DEVOY, SENIOR CURATOR, ROYAL OBSERVATORY, GREENWICH SAYING: "One of the reasons why people were so interested in studying the Earth's magnetic field from the 1840s onwards was really because of the emergence of other technologies. So for example you've got more iron components on ships so people were worried about how will this affect my magnetic compass? Is this going to be an issue for navigation? And then with the growth of telegraph networks as well people were starting to realise that this relationship between magnetism and electricity could have consequences for telegraph networks as well. So there was very much this much bigger picture, much bigger interest in magnetism in the 19th century." VARIOUS OF HISTORIC MAGNETIC MEASURING DEVICE
- Embargoed: 20th September 2019 16:58
- Keywords: True north and magnetic north converge A magnetic compass will point to true north for first time in 360 years since 1660 Dr Ciaran Beggan British Geological Survey The Royal Greenwich Observatory earth's magnetic field
- Location: GREENWICH, ENGLAND, UK
- City: GREENWICH, ENGLAND, UK
- Country: United Kingdom
- Topics: Science
- Reuters ID: LVA001AVISH97
- Aspect Ratio: 16:9
- Story Text:For the first time in nearly 360 years, a compass at Greenwich, the site of the prime meridian or zero degrees east or west on all maps, will finally point to true north as it and magnetic north converge.
"If you hold a compass along this line it will point directly toward true north and it's the first time that's happened since 1660," Dr. Ciaran Beggan, a geomagneticist with the British Geological Survey, told Reuters at The Royal Greenwich Observatory.
The earth's magnetic field is caused by huge quantities of liquid iron deep in the planet's core which moves around 20 km. (12 miles) every year because of the rotation of the planet.
"The Earth's magnetic field is actually created by the flow of liquid iron deep in the centre of the Earth and as this iron flows it creates electricity and the electricity also creates magnetism because there is this link between electricity and magnetism," Beggan said. "Because it's liquid it also flows westward all the time and so the liquid outer core drags the magnetic field with it and that's why the north pole, the magnetic north pole position changes all the time."
The Royal Greenwich Observatory was established in 1676 and from 1836 until the 1920s it measured the deviation between true and magnetic north.
The observatory helped establish the definition of zero longitude, paving the way for a global reference system for maps and navigation that we know today.
"It's just interesting because it aligns with this historic meridian. In some ways it's a human construct. The meridian was chosen here but it could have been anywhere else. So it's just a nice coincidence really," Senior Curator at The Royal Greenwich Observatory, Dr. Louise Devoy told Reuters.
Anyone who navigates using a map and compass will be well versed in making magnetic deviation adjustments to their bearings but for the satnav generation the alignment will have no practical impact on everyday life.
"Within your smartphone or your satnav navigation system there will generally be a digital compass and it will know the way towards magnetic north and at the British Geological Survey we provide maps to make the correction towards true north. Now if you are stood here today using a compass there is no correction to make and that's what's unique about this place at this point in time," Beggan said.
The last time Greenwich had zero declination, King Charles II was on the throne. By coincidence, it was Charles who established the Royal Observatory at Greenwich in 1675.
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