Understanding the Kp Index
The Kp Index is the global standard for measuring geomagnetic activity. It ranges from 0 to 9. Think of it as a speedometer for the Northern Lights:
- Kp 0-2 (Quiet): Aurora is dim and hugging the poles (only visible in far north places like Svalbard).
- Kp 3-5 (Unsettled): Aurora brightens and expands south to places like Iceland, Norway, and Northern Canada.
- Kp 6-9 (Storm): A Geomagnetic Storm. The aurora can be seen much further south, potentially reaching the northern United States and UK.
The Solar Cycle
The sun goes through an 11-year cycle of activity. During "Solar Maximum" (the peak), the sun's magnetic field flips, creating more sunspots and solar flares. This leads to more frequent and intense auroras on Earth. We are currently in Solar Cycle 25, which is expected to peak around 2025.
Frequently Asked Questions
Why can my camera see it but I can't? ▼
Human eyes are not very sensitive to color in the dark (our "rods" take over). Cameras can use long exposures (shutter speed) to gather light over several seconds, revealing vibrant greens and purples that might look like faint grey clouds to the naked eye.
What is the difference between Borealis and Australis? ▼
Geography! Aurora Borealis ("Northern Dawn") occurs around the North Pole. Aurora Australis ("Southern Dawn") occurs around the South Pole. They happen simultaneously and are mirror images of each other.