giant magnetic storm (stock image)

In 1770, people living in far-east Asia saw the sky turn a deep crimson for over a week - an event that was recorded in ancient scrolls. Now, scientists have analysed the historical event, and suggest the red hue was caused by a giant magnetic storm (stock image)
In 1770, people living in far-east Asia saw the sky turn a deep crimson for over a week - an event that was recorded in ancient scrolls.

Now, scientists have analysed the historical event, and suggest the red hue was caused by a giant solar storm.

Lost to the annals of time, the event could be the largest recorded solar flare in recorded history.

China, Korea and Japan all saw a deep red sky for nine days in the late 18th century.

Researchers from Osaka University have unearthed new documents which suggest the celestial phenomenon was caused by a geomagnetic storm.

'Historical documents can let us trace back solar activity for millennia,' Dr Hisashi Hayakawa, who led the study, told Live Science.

Previously, the 'Carrington' event of 1859 was considered the benchmark for huge solar storms.

To solve the 300-year-old mystery, researchers looked at historical records from China, Korea and Japan from the 18th century, to see if there were mentions of auroras.

They also looked as records from Captain James Cook's missions on the HMS Endeavour, as well as sunspot drawings from the period by German astronomer Johann Caspar Staudacher.

By carefully looking through 111 ancient antique documents, the researchers discovered that this Asian occurrence had sun spots twice as large as the one's observed during the Carrington event.

'Sunspot drawings from 1770 reveals the fact that sunspots area was twice as large as those observed in another great storm of 1859, which substantiates this unusual storm activities in 1770,' the authors said in their study, published in The Astrophysical Journal Letters.

The researchers also found auroras were seen farther south by the crew aboard the HMS Endeavour near Timor Island in Southeast Asia.

Because these auroras took place at low latitudes, it suggests a powerful geomagnetic storm caused them.

The researchers believe that the eerie blood-red glow was likely caused by the ejection of 'several huge, sequential magnetic structures in short duration into interplanetary space, resulting in spectacular world-wide aurora in mid-September 1770.'

Before now, the event was believed to have been over two days, but new evidence suggests it was far longer, lasting well over a week.

The skies were a deep red for nine days, setting a new record for a geomagnetic aurora as the Carrington event is believed to have lasted a maximum of four days.

Unlike solar flares, which travel at the speed of light once emitted and reach Earth in about eight minutes, CMEs are larger events where giant, expanding clouds of magnetised particles are launched into space and take one to three days to reach Earth.

Although the researchers are not entirely sure if the event of 1770 was a solar flare or a CME, they added: 'The long duration of the auroral observations in 1770 indicates long-lasting magnetic storm activities resulting from continuous solar activity, such as multiple, consecutive CMEs.'

This period of speculated intense solar activity created a phenomena which endured in folklore for centuries.

However, if it happened now the consequences would be far more severe.

'Modern civilisation heavily relies on satellites and large-scale power grids,' the researchers wrote. 'If such events were to strike the Earth now, the consequences could be catastrophic.'

A huge solar storm would have the potential to disrupt flights, disturb satellites and render GPS pointless.

A previous study suggested that if a solar storm the size of the Carrington event was to happen now, it would cost North America $2.3 trillion (£1.7 trillion).

The authors of that study said that the possibility of it happening in the future is 'almost inevitable.'