I have lived all over the country, but I have only seen them in one place, Eau Claire, Wisconsin. It was in winter and right after a snow storm. The skies cleared and the stars were glowing brightly in the sky. Suddenly the sky became covered with many brilliant shades of green. The scientific term for those beautiful is Aurora Borealis or Northern Lights. I wish I had a camera that could have taken a decent picture of what I saw, but the camera I had at the time was a simple film camera that was not capable of taking pictures of the night sky.
Let’s start with the definition of an Aurora. According to the NOAA Space Weather Prediction Center “The Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) are the result of electrons colliding with the upper reaches of the Earth’s atmosphere. (Protons cause faint and diffuse aurora, usually not visible to the human eye.) The electrons are energized through acceleration processes in the downwind tail (right side) of the magnetosphere and at lower altitudes along auroral field lines. The accelerated follow the magnetic field of Earth down to the Polar Regions where they collide with oxygen and nitrogen atoms and molecules in Earth’s upper atmosphere. In these collisions, the electrons transfer their energy to the atmosphere thus exciting the atoms and molecules to higher energy states. When they relax back down to lower energy states, they release their energy in the form of light. This is similar to how a neon light works.” Auroras usually form between 50 and 310 miles above the surface of the Earth.
Now that we know how auroras form it’s time to explore some new research. Aurorae (Yes, that is the correct plural spelling.) According to Astronomy.com are not identical between the North Pole and the South Pole. ” One particular mystery is that the northern and southern lights don’t always match up like researchers would expect. For years, scientists assumed that aurora borealis and and aurora australis would mirror each other. ” But recent research has shown that’s not the case. And now a team of scientists from the University of Bergen in Norway thinks they have an answer.”
The Earth’s core is molten metal and that makes the Earth act as a giant magnet. The magnetic field created surrounds the Earth and protects us from the dangerous radiation emitted by the sun which produces the Solar Wind. Back to Astronomy.com to explain what happens. “The magnetic energy of the solar wind is constantly ripping apart lines from our planet’s field and bending them back over the poles into the tail where they reconnect with each other. In between is a pocket of charged particles that will occasionally squeeze off a blob of plasma. These plasma blobs will sometimes trail away behind us, but they can also get sucked back towards Earth, where they often find the chink in Earth’s magnetic armor.” “When these high-speed, energetic particles slam into the molecules floating around the planet, they often excite them enough to release a dazzling shower of iridescent, sinuous light. We call then auroras, and they usually appear near both the North and South poles.”
The new information the researchers found is that the solar wind doesn’t always strike the Earth head on so the stream can twist the magnetic field lines so that they do not match exactly at both poles, thus creating an aurora borealis and an aurora australis that are not mirror images of each other. Sometimes these strong solar storms send a powerful solar wind straight at Earth. The bending of the wind by the magnetic field protects us from the worst of the radiation pulses from the Sun. If all of the strong solar winds hit Earth directly it would disrupt our satellite communications all over the world and could even render those satellites useless and in need of being replaced.
We can be thankful for having a powerful magnet at center of the Earth. For a more detailed explanation check out the following video.
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