Aurora Borealis

aurora iss

Every night when the skies are clear, I look outside to see if the Northern Lights are shining. I check SpaceWeather.com and SpaceWeatherNow websites to see where the current auroral loop is on Earth. On the evening of June 1, 2013, I checked the website and saw that the auroral loop was over Minnesota, so I took a short drive over to the back of Wayzata High School and shot a few pictures. This is my favorite ... the Northern Lights with the International Space Station flying through the picture. I often wish I lived farther north so I could see the Northern Lights more often. I just find them fascinating, and I hope that this page will help you appreciate these phenomenon and understand their cause a little better.

It has taken a bit of digging, but I think that this page in the course is really fascinating. Several years ago, I had a student in my Hopkins class named Keith Wygant. Both of his parents are physicists at the University of Minnesota working actively in the field of Solar Activity, and part of a satellite project that monitors Coronal Mass Ejections. Their concern is to predict the timing of such an ejection with the Earth's atmosphere, thus predicting the potential negative effects of these powerful solar storms. Even more important is knowing the timing of the impact so astronauts can shield themselves from the harmful radiation. I learned a great deal from the Wygant parents, John Wygant, PhD and Cynthial Cattell, PhD, during a visit at one of our parent-teacher conferences. While I am not an expert in the field of the Sun's magnetic field, what I learned from them has helped me appreciate the awe-inspiring activity that occurs at the Sun's photosphere. Often the results of these turbulent outbursts is the Aurora Borealis for those living in the Northern Hemisphere, and the Aurora Australis for those living in the Southern Hemisphere. I first direct you to a website from the University of Tromso in Denmark where there is a wonderful explanation of the Cause of the Northern Lights.

My Attempt to Explain the North Lights

First, you have to understand the properties of electrons and what happens to them when they absorb energy. I refer you to a very important explanatory page that teaches a simplified version of photon absorption and re-emission. This page is the key to understand where the colors come from in the Aurora. Once you have read this page, you will be better able to follow what comes next.

The picture above shows the Earth's magnetic field in relation to the Solar Winds. As the solar wind strikes the magnetic field, it pushes it close to the Earth on the sunward side, and stretches it on the back side. The magnetic field is stretched a great distance, and forms a magnetotail.

As the solar wind strikes the Earth's magnetic field, the ions in Earth's upper atmosphere are pushed all the way to the tip of the magnetotail. As these ions are snapped back to the Earth by the magnetic field, the positive ions will flow to the negatively-charged South Pole, and the negative ions will flow to the positively-charged North Pole. As these ions return, they will release their absorbed photons. The colorful curtains of the Aurora are the result of these flowing ions releasing their absorbed photons during their fall to the magnetic poles. As you learned in the Photon Emission page, each atom will release colors depending on that atom's structure and ionic state.

Since ions are falling simultaneously at the North and South Poles, one will find the Aurora present at the North and South Poles in nearly identical fashion.

The particular colors of the Aurora and the extent of the Auroral display depend on the strength of the solar wind. There is always an auroral loop at the highest latitudes, but this loop will extend farther and farther south depending on the strength of the solar wind. During an intense solar storm, the Auroral Loop will extend down to the northern states of the US. In extreme instances, this loop can be seen as far south as Arizona and Florida. The image below shows the extent of the Auroral Loop during the March 14, 1989 Solar Storm.

The more intense the solar storm, the farther south the aurora will be seen, and the more colorful the display. Click on the center pictures for more information about them.

aurora church

The image above came from the Spaceweather.com site and for me, this is one of the most beaufitul photographs of the aurora that I have ever seen. It is NOT my photograph. The credit belongs to: Taken by Jonathan on February 19, 2014 @ Grand Forks, North Dakota

Diurect link: spaceweather realtime aurora

Continuing On

Once you have browsed through that site and gained a better understanding of the causes of the Aurora, it is now time to look at some pretty fantastic pictures. You can visit the Borealis 2000 site to see photographs from the recent two peaks of the Solar Sunspot Cycle. Click on the Flickr Site for a look at some of the best photographs of the Aurora. Then you can go to two more websites for:

1) Current images of the Sun and links to spaceweather.

2) Immediate location of the auroral activity on a global scale.

Below are a few photographs from the above-listed websites to give you a taste of what you will find upon your visits :) These four images were taken following a coronal mass ejection August 1, 2002. The first two images were from the evening of August 2, the next from August 3, and the last from August 4. They can all be found at the SpaceWeather website Aurora Gallery, and are presented here in my hopes that you will visit the website, look for Solar Alerts, and go outside more often at night to look for them. It was clear in Minneapolis the evenings of August 2 and 3, 2002 and I was able to see these displays with my wife from our backyard in the Twin Cities area. One particular ribbon of light stretched from west to east and first looked like a long contrail from a high altitude jet. When the "contrail" began snaking and undulating in the sky I knew it was an auroral display.

The photographs above show different auroral displays. I copied these from the Aurora Gallery within the Spaceweather.com website. None of these pictures can be reproduced without the permission of the actual photographers or Spaceweather.com itself. They are included in here to give you a glimpse of what you might see on a given night during the Minnesota autumn. I included some of my own pictures form the Northen Lights display on November 7, 2004.

Back to Solar Features and Events, or the Sun Introduction, or to the Syllabus.


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