The northern lights are nature’s very own magnificent light show. They are the mesmerising end result of electrically charged particles from the sun colliding with the Earth’s upper atmosphere. Though more frequently witnessed from the polar regions, the UK and other places on similar latitudes are lucky enough for the aurora borealis to occasionally grace their night sky.
But recent reports now claim the phenomenon may no longer be visible from places such as the UK – instead confined to the North Pole. But is this correct?
The northern lights are driven by activity on the sun and the sun’s activity waxes and wanes over an 11-year period known as a solar cycle. The number of large-scale aurora events, the type that is visible from places such as the UK, tends to follow this cycle. But each solar cycle is different, with the maximum and minimum activity varying between each cycle.
Predicting solar activity
Current predictions suggest that we are headed for a period of particularly weak solar cycles, where the solar maximum of each cycle will not result in much solar activity. We call this a grand solar minimum.
Global Warming Art/Wikipedia
Grand solar minimums can last for several decades or even centuries and have occurred throughout history. Although solar output does decline during these periods, it doesn’t mean that we are heading for a new ice age.
A study recently published in Nature has modelled the perhaps most well-known grand solar minimum, called the “Maunder minimum”. This particular grand solar minimum started in 1645 and finally ended 70 years later. During this time only 50 sunspots, structures on the sun that act as a measure of its activity, were observed. This is compared to the 40,000-50,000 that we would expect during a period of “normal” activity lasting that long.
NASA/SDO/AIA/HMI/Goddard Space Flight Center
The authors of the study found that during the Maunder minimum, the solar wind, which drives the aurora, dramatically weakened. They also illustrate that as the solar wind weakens, so too will the aurora.