--------- #1262 - Are Solar Flares Dangerous?
- Would you like to see a video of a Solar Flare? Search internet for:
------------------ www.onorbit.com/node/3475
- Solar flares appear to be happening more often ,but really, we simply are seeing more with better equipment and we are more concerned because our newer technology is more susceptible to damage from Solar Flares. This review covers these dangers and what causes them.
- Most of us forget that astronomers studying the stars have the best example just 93,000,000 miles away. Most everything we know about stars we have learned from our nearest star.
- The NASA Solar Dynamic Observatory, SDO, is providing fantastic pictures and scientific data about the Sun. It was launched February, 2010, and has been in orbit 23,000 miles above the Earth beaming high-resolution pictures at 18 megabytes per second.
- On August 1, 2010, SDO recorded the first Solar Flare outburst from the Sun. The aurora borealis colorful displays were over the U. S. 2 days later.
- Really intense solar storms were recorded on September 1, 1859 when the northern lights were seen as far south as the Caribbean Sea. The flare was visible to the naked eye. It was so intense when it hit the Earth it set telegraph systems on fire. We have measured this intensity by studying the ice in Greenland. The ice contained traces of nitrates and beryllium 10. Studying proportions allowed scientists to measure the strength of the flare that occurred in 1859 and it was a big one.
- Flares occur often on the Sun. Most of them are not pointed directly at us. However, on some occasion Mother Earth is directly in the line of fire.
- In 1921 a solar flare knocked out the signaling system for the New York City rail lines.
- March 6, 1989, the power grid in Quebec was knocked out for 9 hours.
- August 16, 1989 another solar flare hit.
- November 4, 2003, solar flares caused electrical blackouts in Sweden and destroyed a $640,000,000 Japanese science satellite. The electromagnetic spectrum of flares was measured to be above 100 Ghz for the first time (X45)
- April 2, 2001 (X20)
- October 28, 2003 (X17)
- September 7, 2005 (X17)
- February 17, 2011 (X2)
- To see the list of recorded flares and their relative strengths search internet for:
-------------------- http://www.spaceweather.com/solarflares/topflares.html
- Our modern, globally connected, electronic society is more vulnerable than ever to our stars spontaneous eruptions. It is becoming essential that we learn how to predict and protect ourselves from our active star. It is only 8 minutes way at the speed of light. Slower plasma particles arrive 1 to 3 days later.
- Our Sun is big. Its volume could hold 1,300,000 Earths. Its nuclear fusion converts 655,000,000 tons of hydrogen into helium every second. The temperature at the Sun’s core is 28,000,000 degrees Fahrenheit. Gamma Ray photons leaving the core take millions of years bouncing through layers to reach the surface of the Sun. At the surface the temperature is 10,340 degrees Fahrenheit. Above the surface solar gases continue far into space beyond the visible edge of the corona. In fact, there is a solar wind blowing through the entire solar system.
- What causes these solar eruptions? The Sun rotates at different speeds. 24 days at the equator and 30 days at the poles. This difference shears the gases and tangles the electric currents and magnetic fields. Every 11 years the Sun’s north and south poles flip reversing the magnetic fields. These disturbances to magnetic fields create sunspots on the surface. The spots are darker because they are cooler with gas leaving the surface with the magnetic fields and that are arcing into space. Sunspots are still hot they just look cooler because they expose cooler internal layers of the Sun’s surface.
- A sunspot requires a minimum of 1,500 Gauss of magnetic field in order to occur. The flare can release 60,000,000,000,000,000,000,000,000 joules of energy. It contains a plasma which is simply charged electrons and atomic nuclei heated to 10 million degrees. These charged electrons and protons in the plasma are accelerated to near light speeds as they fly through the magnetic fields. The accelerating electric charges emit radiation across the entire electromagnetic spectrum. Billions of tons of charged material are hurled into space at more than 1,000,000 miles per hour.
- When the Sun is quiet there is one flare a week. When sunspots are active in their 11 year cycle there are several flares each day. If the flare happens to be aimed right at us the charged material will enter Earth’s magnetic field in 1 to 3 days. ( called the Earth’s magnetosphere).
- Magnetic field lines are semi-circular loops with footprints on the surface of the Sun. The loops are like magnetic ropes wrapping around a center axis and twisting around each other. The twisted ropes carry a strong electric current. The temperatures inside the ropes are heated to 10,000,000 degrees. The flares create a wave on the surface of the Sun much like a rock hitting the water in a pond. But, these waves are magneto sonic waves traveling at 4,500,000 miles per hour across the surface. The periods of the waves from crest to crest varies from 30 to 200 seconds. The wavelengths vary from 60,000 to 120,000 miles between peaks.
- There are also sound waves on the surface of the Sun. SDO’s instruments measure the directions and strengths of magnetic fields and the vibrations occurring on the surface. There are sunquakes or pulsations caused by gases heaving up and down at speeds of 700 miles per hour. These become sound wave vibrations that flow across the Sun’s surface. The waves move faster through hotter gas, and, accelerate when moving through gases flowing in the same direction. This data is used for computer simulations to create pictures of the turbulence on the Sun’s surface. In fact, sunspots can be mapped on the far side of the Sun days before they rotate into view.
- After all these descriptions of activity it may surprise you that science is actually concluding that the Sun’s activity is actually slowing down. It’s magnetic activity is growing weaker. When this happened in 1645 it lasted for 70 years creating the ‘Little Ice Age on Earth. ( called the Maunder Minimum).
- We are in cycle 25 of the measured sunspot activity. In 2008 and 2009 the Sun was unusually quiet. Normal predictions would expect more activity in 2013 and 2014. This could have a significant effect on projections of Global Warming. But, who knows? The Sun is a variable star and we live in its outer atmosphere. Our own magnetic field is what protects us. Like the weather the Sun’s activity is something we will have to learn to live with.
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To learn more:
(1) #1156 Review: “ When will the next solar flare hit the Earth?”
(2) #850 Review: “ How much energy is in a solar flare?”
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707-536-3272, Tuesday, June 21, 2011
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