What Causes the Northern Lights
A breathtaking display ignited by the Sun’s electrically charged particles meeting Earth’s atmosphere
The Northern Lights, also known as the aurora borealis, are caused by electrically charged particles entering the Earth’s upper atmosphere at a very high speed [2] [4]. These particles, known as the solar wind, originate from the Sun, which is constantly emitting waves of particles that travel between 300 and 500 km per second in all directions [2]. When these charged particles hit the atoms and molecules high up in our atmosphere, the atoms become excited and then emit distinctive colors as they decay back to their original state [2] [4]. The aurora’s characteristic wavy patterns and ‘curtains’ of light are caused by the lines of force in the Earth’s magnetic field [1]. The shape of Earth’s magnetic field creates two auroral ovals above the North and South Magnetic Poles, which is why auroras occur almost every night in the northern sky, from August to May [6].
Citations:
[1] https://www.rmg.co.uk/stories/topics/what-causes-northern-lights-aurora-borealis-explained
[4] https://www.space.com/15139-northern-lights-auroras-earth-facts-sdcmp.html
[5] https://spaceplace.nasa.gov/aurora/
[6] https://www.asc-csa.gc.ca/eng/astronomy/northern-lights/what-are-northern-lights.asp
