What is the aurora? This mesmerizing natural space weather phenomenon has puzzled people for centuries. The aurora borealis and aurora australis are two types of auroras that can be seen in different parts of the world.
These light shows occur when charged particles from the sun collide with atoms in Earth’s atmosphere, causing them to glow. This blog post will discuss the science behind the aurora and what causes this amazing spectacle.
What is the aurora borealis (aurora australis)?
The aurora borealis, also known as the northern lights, is a natural light display caused by the collision of charged particles from the sun with atoms in the Earth’s atmosphere. The charged particles interact with the atmospheric atoms, causing them to emit light. The aurora borealis typically occur in the high latitude regions of the Northern Hemisphere, such as Alaska, Canada, and Scandinavia.
The aurora australis is the southern counterpart of the aurora borealis and can be seen in high latitude regions of the Southern Hemisphere, such as Antarctica and Southern Australia, and New Zealand.
Why does the aurora happen?
The aurora is one of nature’s most spectacular light shows. But what causes this colorful phenomenon? The answer lies in the sun. Solar activity, such as solar flares and coronal mass ejections, can produce tremendous amounts of charged particles blown toward Earth by the solar wind.
When these particles enter the Earth’s atmosphere, they interact with atoms and molecules of oxygen and nitrogen. This interaction creates light, which is visible to us as the aurora. While the aurora typically occurs in polar regions, it can also be seen occasionally at lower latitudes during strong solar storms.
When can you see the aurora?
The best time to see the aurora is during the fall and winter months when the nights are longest, and there is less interference from daylight. The best viewing conditions also occur when there is clear weather and dark skies. The best chance to see the Northern or Southern Lights is above 60 degrees of latitude.
For these reasons, many people travel to locations near the North Pole, such as Alaska or Iceland, to see the aurora. However, it is also possible to see the aurora at lower latitudes, especially during high solar activity.
The colors of the aurora and what they mean
The vibrant colors of the aurora have long captured the imagination of sky-gazers. But what do those colors mean? Scientists believe that different types of atoms and molecules produce different colors in the upper atmosphere.
For example, green auroras are typically caused by oxygen atoms at lower altitudes, while red auroras are often the result of oxygen atoms at higher altitudes. If you see blue, that is nitrogen atoms at low altitudes, and purple is nitrogen at higher altitudes.
We’ve summarized this all in the chart below, from the highest to the lowest
- Above 150 miles: red, oxygen
- Up to 150 miles: green, oxygen
- Above 60 miles: purple or violet, nitrogen
- Up to 60 miles: blue, nitrogen
Can you really “hear” aurora?
When most people think of the aurora, they think of the colorful light show seen in the night sky. However, the aurora is more than just a pretty display; it also makes a sound.
For years, people have reported hearing strange noises during auroral displays, and recent research has shown that these reports are not just figments of the imagination. Scientists believe that the aurora produces a low-frequency hum that is too faint to be heard by human ears. But scientists doubt it’s actually the aurora itself making the noise.
Where to find more information on aurora
There are many resources available for those interested in learning more about this natural phenomenon. The website of the Aurora Borealis Observatory (auroraborealisobservatory.com) is a great place to start. This site offers a comprehensive guide to aurora, including information on where and when to see them and photography tips.
The Aurora Forecast app (available for iOS) is also an excellent tool for aurora hunters, providing real-time information on the best locations to see the northern lights.
Happy aurora-gazing, and good luck!