Southern lights New Zealand
What is an aurora?
Auroras are electrically charged particles from solar winds that enter the Earth’s atmosphere and react with its gases.
Solar winds are part of “space weather”, which is a stream of highly energised particles and electromagnetic radiation emitted from the sun. The particles are blown around in space at a very high speed and temperature – just like they are being blown about in the most extreme wind ever!
What usually protects the Earth from solar wind is the magnetosphere, which is constantly changing in size depending on the solar winds. The magnetosphere stops solar winds and other cosmic rays from entering the Earth’s atmosphere (and killing us all). However, an aurora is formed when some of the charged particles from the solar winds breaks through the magnetosphere at the north and south poles and reacts with the Earth’s atmospheric gases. Energy is transferred between the gases and solar wind electrons. Any excess energy becomes the pretty lights that you see in the aurora.
The colours of the aurora are due to a number of factors: the type of gas molecule, the electrical state at the time of collision, and the type of solar wind particle that the gas collides with.
The best time to view the SOuthern Lights
Unfortunately, the Southern Lights are not very predictable. They don’t run on a schedule. In fact, they tend to occur with only 30 minutes notice!
Although auroras happen all year round, the best time to see them in New Zealand is during the winter months (March to September). The widest part of the aurora is when the sun is on the opposite side of the Earth to where you are, so around midnight is best.
You can check various websites for the Aurora Australis forecast, which measures the aurora strength in Kp. Kp ranges between 0 and 9 – 0 being the weakest, 9 being the strongest. Anything classed as Kp5 or above is considered a geomagnetic storm (see below).
There is a solar cycle that creates higher solar wind activity. However, it is said that it only occurs every 11 years and the last one was 2013… So we can’t get excited about that just yet.