Aurora Borealis
Have you ever looked up to the sky and saw the aurora borealis? Or, have you ever seen them in pictures or videos?
I have, and I find them truly captivating.
The beautiful auroras are cast over the North and South pole skies. The lights in the North pole are called aurora borealis. The lights in the South Pole are called aurora australis.
What Is The Aurora Borealis?
Auroras are displays of light in the sky with colors ranging from pale green, red, blue, and purple.
Auroras have a long history. Not only have humans known about the Northern lights for thousands of years, but also have depictions of them in cave paintings and modern art. The lights have inspired mythological creatures, driven folklore, and impacted history, religion, and art.
One of the first citings was in 2600 B.C. In China. The mother of Yellow Empire Shuan-Yuan, Fu-Pao, saw sharp lighting moves around the star Su, which is part of the constellation Be-Dou.
In 1619 A.D. Galileo Galilei created the name “aurora borealis” after the Roman goddess of morning. He misconstrued that auroras were the sunlight reflecting from the atmosphere.
Auroras are still influencing our modern world. In 2001, Maida Withers directed a dance with an international cast that was inspired by the auroras.
How and Where Does It Form?
The auroras start from the sun. The sun has six layers: The core, radiation zone, convection zone, photosphere, chromosphere, and corona. The corona is the outermost layer of the sun and is millions of degrees Celsius. The extreme heat causes the hydrogen and helium atoms to rise to the surface of the sun, creating protons and electrons. These electrons and protons are grouped and move fast enough to escape the sun’s atmosphere. They are a storm of plasma and charged gas. This is the solar wind or solar plasma.
The plasma travels at 400 km/s across the solar system and sometimes is directed to the Earth’s magnetic sphere. The magnetosphere is formed by the earth’s magnetic currents and shields the plasma from entering the Earth.
Way to go magnetosphere!
The shield extends 64,000 kilometers and is shaped like a donut. The North and South geomagnetic poles mark the tilted axis of the Earth’s magnetic field.
When the solar wind hits the magnetosphere it is strong enough to distort the shield, but thankfully not strong enough to break it. The plasma travels along the magnetosphere to the North and South pole. The magnetosphere in the North and South pole are weaker, so solar plasma enters the Earth’s atmosphere at the poles. The stronger the solar wind, the bigger the holes are in the magnetosphere, the more auroras we can see.
Once the plasma comes into contact with air, which is 99% nitrogen and oxygen atoms, it puts the atoms into an excited state. An atom is excited when it has enough energy for its electrons to jump around into higher orbits around its nucleus. Atoms in an excited state are not stable. The atoms in our atmosphere go back to their ground state (the total energy of electrons can not be lowered by transferring one or more electrons to orbitals) and release energy as photons.
These photons are the auroras we see.
And they don’t just appear on Earth. NASA has spotted them on other planets as well. Just like Earth, Other planets in our solar system have magnetic shields that prevent the plasma from the sun from hitting the planet. It is deflected and results in spectacular lights on multiple planets.
NASA astronauts can also see the northern lights on Earth from space.
The Colors
As the plasma comes into contact with the nitrogen and oxygen atoms, depending on how much of each atom there is, different color auroras form. Oxygen creates wavelengths in red, yellow, and green. Oxygen at 60 miles above the Earth forms the yellow-ish green auroras, and the oxygen at 200 miles above the Earth creates the rare red lights. Nitrogen creates blue and purple.
Why Are the Auroras Important?
The auroras teach us about the impacts of solar storms on Earth
In some cases, a powerful solar storm from the sun called “coronal mass ejection” unleashes huge waves of charged particles. When these rare storms occur, we see the auroras in an even more remarkable way. However, the auroras are not just pretty lights. They teach us about how solar storms affect life on Earth through electronics and communications. They guide us to the next big steps in our knowledge about space and how Earth fits into it.
In 1859, a storm so powerful hit Earth that it powered a telegram from Boston to Portland, Maine with the equipment unplugged.
Auroras with navigation
Also, until recently, scientists believed that auroras cause disruptions in navigational systems. Researchers at the University of Bath have found that the plasma turbulences from the Northern lights are not causing these disturbances in navigation systems. Instead, they discovered it was “new, unknown mechanisms” that were causing the disruptions.
“The researchers believe this heightened understanding of the Northern Lights will inform the creation of new types of GNSS technology which are robust against the disturbances of the Northern Lights, and help influence GNSS regulations used in industries such as civil aviation, land management, drone technology, mobile communications, transport and autonomous vehicles.” (Auroras and Navigation)
Curiosity
Although humans have known about auroras for thousands of years, we still do not have all the answers. And there are ways to help our world move forward in our curiosity.
Zooniverse is a platform that helps scientists transcribe research on a variety of topics, such as pollinators, beluga whales, and the auroras. The simple questions you answer from looking at a picture greatly help scientists and researchers understand this natural phenomenon. And who knows, maybe you could make a scientific discovery. I have an account that I use to transcribe research, and I hope you will consider it as well.
The best places to watch the auroras are in the arctic circle, specifically Alaska, Canada, Iceland, Greenland, Norway, Sweden, and Finland. Best places in North America to see the lights are in Canada, specifically in Yukon, Nunavut, Northwest Territories, and Alaska. They can also be seen near the South pole.
Next time you see the Northern or Southern lights, take a moment to marvel at the beauty that is right in your planetary backyard.
Key Takeaways
- Electrons and protons from the sun travel to the Earth’s magnetosphere that extends 64,000 kilometers. The particles come into contact with the oxygen and nitrogen atoms in the Earth’s atmosphere and form the auroras.
- Auroras appear on other planets as well.
- Auroras continue to impact history, religion, and art.
- We are still learning more about auroras.
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