What are solar storms? Where do they come from? What else happens in the Sun that could affect the Earth and its inhabitants?
The Sun is a star that, alike millions of stars in the universe, produces huge amounts of energy. In one second, our Sun produces enough energy to meet the energy demands of the United States for the next nine million years. Such energy is generated by a nuclear fusion that takes place within the Sun, where the hydrogen atoms transform into helium.
Although our planet orbits over 150 million kilometers away from the Sun, the solar nuclear fusion processes, such as the “solar flares” (also called “solar storms”), have an impact in our lives.
A “sunspot” is an area on the surface of the Sun where a strong electromagnetic field has produced a decrease in the average temperature from 6000°C to 2700-4200°C. This region appears as a dark spot on the surface of the Sun. “Sunspots” can remain for days or weeks, and some of them are so big that they can be seen from the Earth without a telescope.
“Solar flares” or “solar storms” are intense explosions or temporary outflows of energy that can last minutes or hours.
Solar storms take place in active regions around sunspots, where the intense magnetic fields penetrate the external layers of the Sun, connecting them with the inner part and generating a reaction. These flares are the largest explosive events of the Solar System and some of them produce energy equivalent to 40 billion atomic bombs like that thrown over Hiroshima.
How do solar storms reach our planet?
Thirty minutes after a solar flare of great magnitude, the Earth is showered by energized solar particles which, among other things, can significantly increase radiation. In October of 1989, a series of very strong solar storms took place. If, at that moment, an Earth astronaut would have been standing on the Moon surface, outside his spacecraft, he would have died due to the radiation produced by the solar particles.
A few days after a solar flare occurrence, a cloud of electromagnetically-charged solar particles reaches the Earth, hitting part of our atmosphere and creating an Earth geomagnetic storm. The “aurora borealis” are the most benign visual manifestations of these geomagnetic storms caused by solar activity.
The U.S. Aviation Administration, as well as others worldwide, routinely receive solar storms alerts because they are aware of the radio communication problems they can cause. The navigation systems used by planes and ships around the world, such as LORAN, OMEGA or the GPS, can err by many kilometers during a geomagnetic storm or during times of high solar activity.
Satellites are also affected by solar geomagnetic storms. In March of 1989, during a strong geomagnetic storm, four satellites were left out of order for a week.
When a magnetic field moves close to a cable, an electric current is induced in the cable. During a geomagnetic storm, the magnetic fields induce electric current in the long transmission lines used by electricity companies, causing trouble. In March of 1989, in Quebec, six million users were left without electricity for nine hours as a result of a huge geomagnetic storm. This 1989 storm is just a small sample of what the “solar flares” foreseen for 2012 by a NSA report could produce.
Galileo Galilei discovered the sunspots in 1610 and, from that moment on, we have made a great progress identifying and interpreting them. Through the observation of these sunspots we have learned to determine which solar cycles present a magnetic activity.
Since 1755, when the detailed recording of these spots on the surface of the Sun began, we have had 23 magnetic solar cycles. These days, we’re in the middle of the 24th cycle. Although scientists know that the first half of the magnetic solar cycle have less solar activity, we should already have had some significantly strong “solar storms”. For now, the predictions about the gigantic “solar storms” that would happen during the second half of the 24th cycle (at some point between the end of 2012 and the beginning of 2013) don’t seem to be very accurate. The last “solar flare” rated Class X, those which can really damage planet Earth, happened in February of 2011. This cycle is still under observation because it doesn’t present as many solar storms as expected. However, as we see day after day, it’s impossible to predict nature’s behavior, specially regarding something so complex as our Sun.