Aurora

An aurora is a natural light display in the sky that is caused by particles from the sun interacting with a planet’s magnetic field.

The most well-known aurora is the aurora borealis, the shimmering display of colorful lights that sometimes appears in Earth’s Northern Hemisphere. The phenomenon is also commonly called the northern lights. The aurora that occurs in the Southern Hemisphere is called aurora australis or the southern lights. (The word borealis is Latin for boreal, which simply means “northern.” The word australis is Latin for austral, which simply means “southern.”)

On Earth, auroras appear in many colors ranging from green and pink to red, yellow, and blue. Both the northern and southern versions can be called aurora polaris because they occur around Earth’s poles, but this term is not commonly used.

Auroras are not exclusive to Earth and occur on every planet in our solar system except Mercury.

If you happen to find yourself near the North Pole or the South Pole, you might get the chance to see a natural light display that puts any fireworks to shame. This light show is called an aurora and humans have been amazed by it for thousands of years. Recorded sightings date back to the ancient Babylonians and Assyrians, and the phenomenon may even be depicted in some ancient cave paintings. The lights are named after Aurora, the Roman goddess of the dawn. The name aurora borealis is thought to have been coined by Italian astronomer Galileo Galilei in the 1600s.

An aurora is a natural light display that occurs in the skies close to Earth’s north and south poles. The process that results in an aurora starts at the sun. Because it is both very hot and very magnetic, the sun frequently releases charged particles (such as protons and electrons) into space that zip toward the planets, including Earth. Earth is surrounded by an invisible magnetic field that protects it (and us) from this solar wind by bouncing it back into space. However, the magnetic field is weakest at Earth’s north and south poles, and some solar particles manage to enter Earth’s atmosphere close to these areas and collide with Earth’s gas particles (oxygen, nitrogen, etc). These collisions emit light that the human eye can see and this, finally, results in an aurora. The aurora borealis is the northern aurora, and the southern aurora is called the aurora australis.

While these auroras technically appear throughout the year, the human eye isn’t always able to see them. The visibility of an aurora depends on multiple factors such as your location, the weather, and the time of the year. Organizations such as NASA and NOAA that have studied auroras provide information for “aurora hunters”—people seeking to observe the lights. The aurora borealis is easiest to see during winter in cold, northern places such as Canada, Scandinavia, Greenland, Russia, and the North Pole itself, though it is sometimes visible at locations farther south. The aurora australis can be seen in places like Antarctica, Australia, New Zealand, and the region of Argentina and Chile known as Patagonia.

Like many celestial phenomena, the aurora borealis has been seen as an omen or sign of the gods by many different cultures. For example, a bright red aurora was said to have been visible in the skies prior to the death of Julius Caesar as well as the outbreaks of the American Civil War and the French Revolution. This rare “bloody” version of the northern lights was thought to signal incoming bloodshed or violence.

The two auroras on Earth are the aurora borealis and the aurora australis—the northern lights and the southern lights. Many people travel just to see them.

Getty. The aurora borealis as seen in Alaska.

So I think my footage from last night has gone kinda viral 😆

So many questions, here are a few answers…

It was taken at the Aurora Borealis Observatory on Senja in northern Norway.

It was taken on a @SonyAlpha 7sii, which is an amazing camera for astrovideography 😍 pic.twitter.com/D7Z30sO4AP

— Matt Robinson (@Astromackem) November 23, 2020

*jaw drop* 😮 Photographers around Tasmania were treated to a spectacular light show last night! Clear skies provided the perfect viewing conditions of the #auroraaustralis teamed with bioluminescence in the water. Simply stunning!
📸 Ryan Shan pic.twitter.com/rMswQWI1FZ

— Australia in the US 🇦🇺🇺🇸 (@AusintheUS) November 23, 2020

• aurora borealis
• aurora australis
• northern lights
• southern lights
• sunspot
• solar wind  
• magnetic field
• atmosphere
• North Pole
• South Pole

In which hemisphere does the aurora borealis appear? 

A. Southern
B. Northern
C. Eastern
D. Western