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
  

Hello again! I tried to make this blog entertaining and informative and hope you are able to take away some knowledge from this post.  I welcome all comments and opinions on this subject! Enjoy!

From roughly the year 1200 to the year 1800 the Earth was thrown into a Little Ice Age.  The Little Ice Age was a period of time in human history where many people suffered at the hand of a climate we did not understand or prepare for.  This can happen again. The question is why did it start and when will it happen again?  I hope this blog answers some of these questions.

What happened during the Little Ice Age?

• Crop Failure:

-   Across the world the failure of agricultural output created hunger and famine. 

• Towns disappeared:

-   Farms and villages in the Swiss Alps were crushed by glaciers in the mid 17th century.

• Transportation change:

-   In New York City, New York Harbor froze in 1780 allowing people to walk from Manhattan to Staten Island.

-   Iceland had ice surrounding it for miles in each direction.  Harbors closed.

• Geographic change: 

-   Fairs were held on the frozen ice in southern England on the River Thames. 

• Decrease in population:

-   Iceland, in particular, had its population drop by half.  Some believe this was due in part to increased amounts of       fluoride in humans due to 1783 eruption (which added ash to the atmosphere, more on this later). 

-   World population increase slowed and decreased in many areas, especially in Europe.

• Armies walked across water:

-   In 1658 a Swedish army was able to march across ice to invade Copenhagen in Denmark.

• Colonies vanished:

-   The Norse colonies in Greenland vanished by the 15th century due to crop failure and livestock dying in the increasingly harsh winters.

• Permanent snow on Ethiopian mountains:

-   In Africa mountains that do not have snow on them year round today had snow on them for years.

• Ice in June:

-   Lake Superior still had ice on it in June.

• Native American crisis:

-   Leagues were organized to respond to the food shortage among tribes.

• Glacier advancing:

-   Many glaciers, even in Glacier National Park, experienced advancement in the late 18th and 19th centuries.

• Witch-hunting:

-   The lack of crops, cold temperatures, and odd weather contributed to the mass hysteria that was the witch hunts in Europe.  Prosecutors believed witches were destroying crops and changing weather.



Now that we have the effects what were the potential causes of this Little Ice Age?

1.     The Sun- The Sun develops something called sunspots on its surface.  They are basically “cooler” areas of the Sun.  In response to the cooler area with less convection there is a large amount of magnetic activity.  Sometimes this magnetic activity is released in a massive explosion called a CME.  These are what give Earth radiation and cause the northern lights. 

If sunspot activity is reduced there are less CME’s and therefore a smaller amount of radiation/heat reaching Earth.  There was a large reduction in solar activity during the Little Ice Age.  Every 11 years the Sun reaches its solar maximum in terms of sunspots.  We are at solar maximum.

2.    Volcanoes- Volcanoes erupting on the surface of the Earth create ash plumes that travel high into the atmosphere.  Sometimes this ash is so plentiful that it prevents heat from reaching the surface of the Earth.  In turn the Earth cools.  During the Little Ice Age many volcanoes erupted on large scales and sent ash high into the atmosphere.  In fact, in 1815 the volcano Tambora in Indonesia erupted.  The next year was called the “Year Without a Summer.”  Snow and ice were reported in June and JULY in North America!

3.    Thermohaline circulation- The large circulation process of water in the Earth’s oceans is elaborate and vital to our climate.  Salt water is heavier than fresh water.  Because of this a circulation is created in the ocean that carries warm water from the equator north to the coast of Europe.  This is why England has a climate much like the northeast states in the United States (warm water brings warmer air).  If the circulation shuts down England resembles northern Canada.

The theory is that a large amount of fresh water, created by the warming period immediately preceding the Little Ice Age, increased the amount of fresh water from icecaps in the ocean.  This in turn shut down the circulation and caused the northern hemisphere to cool. 

4. Orbital patterns- Cycles in the Earth’s orbit around the Sun can create cooling and warming periods.  If this is true then the cooling process will continue until we reach another ice age in around 4,000 years.  This is a normal pattern on Earth.



So what? Why should any of this matter today? 

The reason I bring this up is because, contrary to the seemingly apocalyptic reporting of CME's from the Sun by the media, the Sun should be at its 11 year maximum for sunspots (which produce CME's).  Though we have had some sunspots there are hardly as many as previous solar maximums.  This indicates that the Sun may be entering a solar minimum, much like that during the Little Ice Age.  If you followed earlier, fewer sunspots mean less heat reaching the Earth. 

What does this mean for us?  Many scientists believe nothing. The impact of the Sun is far less than the impact of greenhouse gasses in the atmosphere.  The gasses will offset the cooling process and prevent another Little Ice Age. 

Other scientists disagree.  The Sun is the MAIN source of heat for the surface of the planet.  Some heat is produced by Earth's core but the amounts pale in comparison to the energy sent by the Sun.  Taking this into account a reduction in solar output would coincide with a direct decrease in latent heat on Earth.  This would lead to a cooling of the planet and in turn a Little Ice Age that may, once again, have similar impacts as the one last millenia.  Given the 7 billion people on Earth, there would mass food shortages and large geographical changes, among other things.

When will this happen?  I am not sure.  The reduction in sunspots seems to just be appearing now.  It is possible the Sun is simply going through a mid-life crisis.  After all it is 5 billion years old and has another 5 billion years left before it burns out.  Next solar maximum may be more impressive than this one.  However, if it is not, then we may start seeing impacts similar to those during the Little Ice Age on Earth.

If a major volcano explodes, such as the super volcano under Yellowstone, then the Earth will certainly be thrown into another Little to full fledged ice age.


What do I think?

Global warming is increasing at a rate unprecedented and it is being contributed to by humans.  In addition to our own contributions there are changes that we are trying to understand on Earth.  Earth goes through patterns and right now it should be cooling, not heating up.  Still, the Sun, if it continues at solar minimum, may quell the speed of global warming in the coming decades due to the decrease in radiation reaching Earth.  Will we see an ice age on the level of the Little Ice Age?  No.  We need to monitor this closely. 

The bottom line: Do not think that tomorrow we will see glaciers crushing towns across the world.  Any climate change takes decades to centuries to complete; however, we should be concerned with the increase in global temperatures and in turn what impacts this will have on our Earth.  Barring any major volcanic eruptions or other unforeseen events, I do not believe we will see another ice age for thousands of years.  In the end the only thing we can do is live in the moment and hope for the best.  The Earth will do what it wants and we are just along for the ride!

Please feel free to comment.  This took a long time to research and started as a sentence but quickly exploded into an essay.  Thanks for reading!


Sources:

Emmanuel Le Roy Ladurie (1971). Times of Feast, Times of Famine: a History of Climate Since the Year 1000. Barbara Bray. Garden City, NY: Doubleday.

Lamb, HH (1972). "The cold Little Ice Age climate of about 1550 to 1800". Climate: present, past and future. London: Methuen.

Stone, Richard (2004-11-19). "Iceland's Doomsday Scenario?"  http://www.sciencemag.org/content/306/5700/1278

Broecker WS (February 2000). "Was a change in thermohaline circulation responsible for the Little Ice Age?"  http://www.pnas.org/content/97/4/1339

Rose, David (2012). “Forget global warming…”  http://www.dailymail.co.uk/sciencetech/article-2093264/Forget-global-warming--Cycle-25-need-worry-NASA-scientists-right-Thames-freezing-again.html  

Mandia, Scott.  “Influence of Dramatic Climate…” http://www2.sunysuffolk.edu/mandias/lia/little_ice_age.html  

“Little Ice Age”  http://www.eh-resources.org/timeline/timeline_lia.html