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What is the Aurora Borealis?
May 12, 2024 at 11:25 AM EDT
By WeatherBug's Ali Husain
The aurora borealis is one of the most fascinating, magnificent light displays that our planet can put on. But what exactly is it?
To truly understand the aurora borealis, we first have to understand the invisible force that protects our planet: Earth’s magnetic field. Below our feet, electrically charged molten iron churns around the solid core at the center of our planet. As a result, a magnetic field is generated that reaches deep into space: on the day-side, extending about six Earth radii towards the sun, and extending a variably huge distance into the nightside, resulting in a comet-like field. The tail of our magnetic field can reach hundreds of Earth radii away from the Sun, well past the moon (which sits about 60 Earth radii away).
Earth’s magnetic field shields us from cosmic and solar radiation that would otherwise be deadly to life on the planet. Without Earth’s magnetic field to protect us, Earth would be uninhabitable.
The Sun is the next key player in the auroras. On the surface layer of the sun, plasma (charged particles) is expelled from the corona, out into the greater solar system. These charged particles travel quickly, with some particles reaching the Earth anywhere from 18 hours to several days after ejection from the surface. The flow of these particles into the solar system is defined as the solar wind.
When the charged particles hit Earth’s magnetic field, the field deflects the particles towards the poles. These particles interact with our atmosphere, depositing energy and causing the atmosphere to light up in the brilliant displays we know as the auroras. In the north, the aurora is the aurora borealis, while in the south the same phenomenon is known as the aurora australis.
While the term “aurora borealis” wasn’t coined until 1619 by the fabled astronomer Galileo Galilei, the earliest record of observed auroras in human history is from 30,000 year old cave paintings located in France. Since then, civilizations worldwide have gazed upon the wonderous beauty of the northern lights and interpreted the fantastic display into their own cultures and traditions, including the North American Inuit people and the Vikings of Scandinavia.
Even with all of our advancements in science, there is still much to be discovered about the auroras on Earth, and beyond. The auroras we witness here on Earth occur on other planets in the solar system, including Mars and Jupiter. On Jupiter, the magnetic field is twenty thousand times stronger than our magnetic field here on Earth, and the resulting auroras that take place are far brighter than the ones that take place above our poles. And yet, auroras on Jupiter aren’t solely driven by the solar wind, but influence by particles blasted into space by it’s close-orbiting moon, Io. Clearly, there is more to this breathtaking display that is yet to be understood.
The sun’s emissions go through a cycle that peaks roughly every eleven years, bringing the brightest and most frequent lights. With the last peak period in 2014, that places 2025 as the next expected year for peak aurora activity. Get your calendars and your travel plans ready!
Sources: NASA, space.com
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Story Image via Pixabay
To truly understand the aurora borealis, we first have to understand the invisible force that protects our planet: Earth’s magnetic field. Below our feet, electrically charged molten iron churns around the solid core at the center of our planet. As a result, a magnetic field is generated that reaches deep into space: on the day-side, extending about six Earth radii towards the sun, and extending a variably huge distance into the nightside, resulting in a comet-like field. The tail of our magnetic field can reach hundreds of Earth radii away from the Sun, well past the moon (which sits about 60 Earth radii away).
Earth’s magnetic field shields us from cosmic and solar radiation that would otherwise be deadly to life on the planet. Without Earth’s magnetic field to protect us, Earth would be uninhabitable.
The Sun is the next key player in the auroras. On the surface layer of the sun, plasma (charged particles) is expelled from the corona, out into the greater solar system. These charged particles travel quickly, with some particles reaching the Earth anywhere from 18 hours to several days after ejection from the surface. The flow of these particles into the solar system is defined as the solar wind.
When the charged particles hit Earth’s magnetic field, the field deflects the particles towards the poles. These particles interact with our atmosphere, depositing energy and causing the atmosphere to light up in the brilliant displays we know as the auroras. In the north, the aurora is the aurora borealis, while in the south the same phenomenon is known as the aurora australis.
While the term “aurora borealis” wasn’t coined until 1619 by the fabled astronomer Galileo Galilei, the earliest record of observed auroras in human history is from 30,000 year old cave paintings located in France. Since then, civilizations worldwide have gazed upon the wonderous beauty of the northern lights and interpreted the fantastic display into their own cultures and traditions, including the North American Inuit people and the Vikings of Scandinavia.
Even with all of our advancements in science, there is still much to be discovered about the auroras on Earth, and beyond. The auroras we witness here on Earth occur on other planets in the solar system, including Mars and Jupiter. On Jupiter, the magnetic field is twenty thousand times stronger than our magnetic field here on Earth, and the resulting auroras that take place are far brighter than the ones that take place above our poles. And yet, auroras on Jupiter aren’t solely driven by the solar wind, but influence by particles blasted into space by it’s close-orbiting moon, Io. Clearly, there is more to this breathtaking display that is yet to be understood.
The sun’s emissions go through a cycle that peaks roughly every eleven years, bringing the brightest and most frequent lights. With the last peak period in 2014, that places 2025 as the next expected year for peak aurora activity. Get your calendars and your travel plans ready!
Sources: NASA, space.com
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Story Image via Pixabay