The Aurora Borealis or ‘Northern Lights’ is a natural light display that majestically dances across the night sky particularly in the high latitude arctic or antarctic regions. On occasions however it can also be seen further south of these areas.
The displays can take many forms, including rippling curtains, pulsating globs, traveling pulses, or steady glows and appear in a range of different colours depending on the altitude. Blue violet/reds occur below 60 miles, with bright green strongest between 60-150 miles. Above 150 miles ruby reds appear
They were discovered in 1621 by French scientist Pierre Gassendi, who named them Aurora – after the Roman goddess of dawn – Borealis, the Greek name for the north wind, Boreas.
The origin of the aurora begins on the surface of the sun when geomagnetic storms cause clouds of gas to be ejected from the sun’s surface. Scientists call this a coronal mass ejection (CME).
If one of these reaches earth, taking about 2 to 3 days, it collides with the Earth’s magnetic field. This field is invisible, and if you could see its shape, it would make Earth look like a comet with a long magnetic ‘tail’ stretching a million miles behind Earth in the opposite direction of the sun.
When a coronal mass ejection collides with the magnetic field, it causes complex changes to happen to the magnetic tail region. These changes generate currents of charged particles, which then flow along lines of magnetic force into the Polar Regions. These particles are boosted in energy in Earth’s upper atmosphere, and when they collide with oxygen and nitrogen atoms, they produce dazzling auroral light.
The storms are measured using a scale called the Planetary Kp index and ranges from 1 to 9 with 1 being low and 9 being a very heavy storm.
The higher the Kp index the higher the likelihood of the Aurora becoming visible and the further South it can be seen. So 5 or 6 would mean it may be visible in Scotland and Northern England and 8+ could make it visible in southern England.
Last night it was particularly visible and appeared for a time over Saltburn on the north-east coast of the England.
Here are a few of my pictures…