On the eve of arrival for a massive X-class solar flare I feel it is appropriate to write a blog regarding what solar flares are and how the affect our planet. 

To understand solar flares we must understand how the Sun works.  

The Sun is a giant fusion reactor.  The core of the Sun is 27 MILLION degrees fahrenheit, partly due to the giant pressure created by the gravity pulling all the mass to the center. At this extreme temperature and pressure the process of fusion can take place.  Fusion, or the process of combining two separate things into one, is not only what lights up the Sun but also gives the Earth light and heat.  To put it plainly two hydrogen atoms are fused to create one helium atom.  The helium atoms are less massive than the two hydrogen atoms that began the process; because of this, according to Einstein’s theory of relativity, the loss of mass means that it has to be converted to energy (E=mc2).  The energy created by this process is emitted as many forms of light: ultraviolet, X-rays, infrared, visible, radio waves, and microwaves. 

The core of the Sun is so dense that it takes energy created by fusion anywhere from 100,000 years to 50 million years to reach the SURFACE of the sun.  From that point on it only takes 8 MINUTES to reach the Earth.  

So that is how the Sun creates its energy but why does it burp it up sometimes?  The burp, mind you, is a solar flare and coronal mass ejection (CME). 

We have to start with the solar atmosphere, or the atmosphere of the Sun.  The Sun’s atmosphere is actually a giant magnetic hodgepodge of energy and power.  It is said to be made up of the Chromosphere, Photosphere, and Corona.   See the image below to better understand the Sun’s layers.  

As mentioned before, the atmosphere of the Sun is EXTREMELY unstable.  All the energy and heat being created in the core allows for massive magnetic shifts on the surface and near the surface.  Look at this image below. 

You can see the prominences, or large loops of gas and particles, being held in by the magnetic field of the Sun.  Meanwhile the surface bubbles with giant grains of plasma floating at the surface.   In many cases the energy from the core is bottled up in the atmosphere until it can no longer be contained by the magnetic field and a CME results.  The CME rushes outward and follows the solar wind, which is always present, but is not a wind as we know it; the solar wind is a steady stream of charged particles emitted from the Sun.  When the solar wind hits the magnetosphere of the Earth northern latitudes see northern lights.  When a CME hits the magnetosphere of the Earth middle and lower latitudes may see northern lights.

Look at the animation below of a CME taking place.  The large disk in the middle is used to block out the Sun so the Corona is visible.  

So what is the difference between a CME and a solar flare?  The best description I have seen comes from a science page a Berkley: “The most obvious difference between a solar flare and a CME is the spatial scale on which they occur. Flares are local events as compared to CMEs which are much larger eruptions of the corona.”

“The left image above shows a bright solar flare erupting in an active region on the Sun. The image on the right shows a CME exploding off the Sun. Notice that this CME is even larger than the Sun itself, which is represented by the white circle in the middle of the frame. Solar flares and coronal mass ejections often occur together, but each can also take place in the absence of the other.”

Solar Flares:

Solar flares occur when large amounts of energy explode in the solar atmosphere and heat the surrounding area to millions of degrees.  This process may take a few seconds or a few minutes.  Flares have the energy equivalent of 160,000,000 megatons of TNT.   They accelerate particles into space and appear to us as bright lights on the surface of the Sun.   When these flares are directed toward Earth we usually receive the energy in a couple days.  Solar flares are classified based on their x-ray intensity.  A, B, C, M, X are the classifications.  The latest flare is an X-class flare, the largest. 

Solar flares typically occur near sunspots, or areas of the sun that are cooler.  Since the sunspots are cooler the magnetic field is concentrated to those areas causing the Sun to become unstable.  Solar flares move near the speed of light and Earth has little time to prepare for their arrival.  Astronauts are bombarded with increased radiation when these events occur because they do not have a magnetic field to protect them like the Earth does.    See the image below for a representation of a solar flare.  

When all these particles reach the Earth they hit a brick wall, the magnetic field, and most are sent past Earth and into space.  The rest of the particles are sent into the magnetic field.  This is called a geomagnetic storm.  The epic battle of the magnetic field against the charged particles results in an aurora.  If a storm is large, you can expect a powerful aurora that reaches into the U.S.  The South Pole has its own aurora, too! 

What happens to electronics and infrastructure when the charged particles hit the Earth?  This is from NOAA and depicts what occurs when the strongest of geomagnetic storms develop on the Earth:

Power systems: widespread voltage control problems and protective system problems can occur, some grid systems may experience complete collapse or blackouts. Transformers may experience damage. 

Spacecraft operations: may experience extensive surface charging, problems with orientation, uplink/downlink and tracking satellites. 

Other systems: pipeline currents can reach hundreds of amps, HF (high frequency) radio propagation may be impossible in many areas for one to two days, satellite navigation may be degraded for days, low-frequency radio navigation can be out for hours, and aurora has been seen as low as Florida and southern Texas (typically 40° geomagnetic lat.)**.

Each geomagnetic storm has its own classification and power.  To see the other levels of the scale please visit:  http://www.swpc.noaa.gov/NOAAscales/ I feel like we should review before I wrap this up considering how complex this blog is:

1. The Sun creates heat and light in its core through the process of fusion.  
   
2. It takes 100,000-50,000,000 years for the light to reach the surface of the sun.
   
3. The light takes 8 minutes to reach Earth.  
   
4. When large amounts of energy explode from the Sun this is called a solar flare.  
   
5. Solar flare energy moves near the speed of light to Earth and arrives in minutes.
   
6. Many times solar flares lead to CME's, which are large explosions of charged particles.  
   
7. These CME's follow the solar wind and bombard the Earth to create aurora.  
   
8. Aurora are pretty to look at but can be dangerous.  Blackouts are possible when large amounts of radiation hit the Earth.
   

Conclusion:  The Sun is enormously complex and this blog, I feel, only touches the "surface" of the Sun.  The descriptions of the fusion, CME’s, flares, and aurora are watered down for the sake of understanding.  Even I have trouble understanding the complexity!  As always if you have any questions please let me know.  Thanks for reading.  

Sources:

• http://sunearthday.gsfc.nasa.gov/2007/locations/ttt_sunlight.php
  
• http://hesperia.gsfc.nasa.gov/sftheory/flare.htm
  
• http://www.enchantedlearning.com/subjects/astronomy/sun/prominences.shtml
  
• http://image.gsfc.nasa.gov/poetry//workbook/page6.html
  
• http://cse.ssl.berkeley.edu/coronalweather/CMEsFlares/index.html
  
• http://www.swpc.noaa.gov
  

Did you know that the Earth has a fever all the time?  This fever is kept in check by ocean and air currents attempting to cool the hot equatorial region of the Earth.  However, the Earth is not very efficient when it comes to lowering this fever through that process because the process itself creates rising and sinking air.  Where air is warm, it rises, where it is cold, it sinks.  

Think about packing an ice chest-  would you put the ice on the bottom of the chest or the top?  If you said the top, you are right.  Cold air sinks thus keeping your food and drinks cool as well. 

It is the same process in the atmosphere (in a way).  The massive circulations on the on Earth are called Hadley Cells… see the following image.

High pressure means air is sinking.  If you go to Antarctica you are actually visiting a desert! I know that seems odd but the central region of Antarctica receives a negligible amount of precipitation a year; however, whatever does fall stays there because it is so cold! The reason Antarctica is a desert is due to the Hadley Cell circulation…low pressure (or rising air and storms) at the equator and sinking air at the poles (or clear skies with no precipitation).  There are more cells in between the equator and the poles but this is the “gist” of the process.

Hurricanes are just one more part of these massive circulation processes on the Earth.  They are the way the atmosphere can fix the disparity between warm and cold, or low and high pressure.  It is always hurricane season somewhere on Earth- it is basically a 365 day conveyor belt of storms coming out of the tropics.  Warm air from the tropics rises into moisture laden air and forms a giant monster that uses an engine of heat from the ocean.  When the hurricane moves into northern or southern latitudes it disperses that heat into the air and water, the air sinks, and the hurricane dies.  If the ocean temperatures are warmer at the tropics and farther north or south, this cycle becomes more violent and persistent.  If the ocean temperatures are cooler at the tropics and farther north or south, the cycle is slower and more spread out. 

Here is a graphic of how a hurricane forms and the typical tracks that they take:

The following section is speculative.  There is no way of proving that this is true or that it did happen; however, science is a matter of speculation and hypothesis.  If the evidence can prove the theory then it is viable.  Please remember this as you read on:  

I did research in college on a theory related to this.  I thought that when the asteroid that killed the dinosaurs struck the Earth it rapidly heated the oceans- especially in the tropical latitudes.  After going through databases and books I found that some scientists investigated this theory and hypothesized that multiple "Mega Hurricanes" formed due to the extremely hot ocean temperatures. 

The water around the region of impact of the asteroid that killed the dinosaurs 65 million years ago superheated to over 120 degrees.  Quickly a huge storm formed over this superheated water, or a hypercane.  Kerry Emanuel of MIT says that when he was playing with his model of hurricanes and typed in a water temperature of over 120 degrees he found that the wind speed of the hurricane became over 500 miles per hour!!! In addition these hurricanes may have been larger than the entire United States! 

Emanuel theorizes that particles from the asteroid impact that killed the dinosaurs are found around the world because of these “hypercanes.”  The hypercanes pulled pieces of the earth high into the atmosphere and distributed them around the world as they tore across the tattered surface.  Another way these giant monster storms can form, according to Emanuel, is through the heating of the ocean from an underwater volcano.

Of course, once the hypercane moved out of the region of superheated water it cooled and turned into a normal hurricane and then just low pressure; still the hypercane cycle continued across the earth until the excessive ocean temperatures equalized (and at that point the entire ocean was warmer).  It is hypothesized that these mega-storms contributed to the extinction of the dinosaurs. 

I no longer have access to the article that I used for this research (it was six  years ago) but I was able to find a shorter version of his theory on this page, if you are interested.

http://alum.mit.edu/pages/sliceofmit/2009/08/14/what-do-you-know-about-hypercanes/

Also, if you want to watch TV’s dramatic cinematic take on the subject please watch this video on YouTube:

http://www.youtube.com/watch?v=JTxj3M3XKcQ

If you have any questions feel free to ask.  Thanks for reading.