Solar Flares Affect Planet Earth

¶ … Solar Flares Affect Planet Earth March 13, 2009 marked the twenty-year anniversary of solar flares that impacted the earth. The sun may not seem like a place with weather phenomenon but the Earth's closest star does experience frequent storms and the occasional flares that radiate to Earth. NASA defines a solar flare as "a sudden, rapid, and intense variation in brightness" that "occurs when magnetic energy that has built up in the solar atmosphere is suddenly released," ("What is a Solar Flare?").

In a recent Scientific American article, Adam Hadhazy describes what took place twenty years ago and how solar flares generally affect planet Earth. In "A Scary 13th: 20 Years Ago, Earth Was Blasted with a Massive Plume of Solar Plasma," Hadhazy notes that solar flares could "pose a serious threat to satellite operations and even to power grids on the ground." The flares release energy "the equivalent of millions of 100-megaton hydrogen bombs exploding at the same time," ("What is a Solar Flare?").

Although regular flares are common and relatively innocuous for earthlings, a coronal mass ejection (CME) is a more severe and intense spewing of a billion tons of plasma or ionized gas (Hadhazy). On March 13, 1989, a CME entered the Earth's magnetosphere, "crashing into it," as Hadhazy describes. Usually the magnetosphere shields the earth from solar wind and "solar jetsam," but the March 13, 1989 CME set of a geomagnetic superstorm. The 1989 CME was "the size of 36 Earths" and "ripped through space at a million miles (1.6 million kilometers) per hour," (Hadhazy).

The sun experiences cyclical weather patterns much like the earth does, except the sun's cycle lasts about 11 years. Currently the solar cycle is at its nadir or "solar minimum," (Hadhazy). The next peak of the solar cycle will be in the year 2012, and is likely to cause intense solar activity. Peaks are referred to as "solar maximums," (O'Neill). The 2012 solar maximum could release a flare as large as "the energy of 100 billion Hiroshima-sized atomic bombs," (O'Neill).

At the other end of the spectrum are the mild solar winds that continually emit from the sun and hardly affect the earth, largely because of its protective magnetosphere. Solar flares and CMEs are relatively predictable because of the cyclical nature of solar storms. The Space Weather Prediction Center and the Space Weather Web site offer daily updates on solar conditions.

Flare prediction involves observation from Earth using telescopes and equipment that can detect radiation signatures, but the detection of x-rays and gamma rays demands equipment staged outside of the Earth's atmosphere ("What is a Solar Flare?"). Several such systems are set up for solar flare prediction at the Earth-Sun Lagrangian Point such as the Advanced Composition Explorer (O'Dell). Unfortunately, x-ray flares that emit from the sun are extremely difficult to predict because x-rays travel at the speed of light and will reach the earth in about 8 minutes (O'Dell).

The last major x-ray flare occurred in 2003 ("O'Dell). Most of the energy from an x-ray flare is absorbed by the earth's ionosphere ("O'Dell). Thus, a CME can be far more dangerous for human societies than an x-ray flare. The first and most subtle observable phenomenon signaling an upcoming solar storm are known as coronal loops, which are "kinks in the magnetic flux form" forced to the surface of the sun due to a buildup of magnetic energy (O'Dell).

Dark spots on the sun's surface then appear, usually in the "footprint" of the coronal loops ("O'Dell). The dark spots visibly signal the buildup of magnetism. NASA describes the phenomenon of solar flares as occurring in three stages: a precursor stage, an impulsive stage, and a decay stage. During the precursor stage, the release of magnetic energy is only triggered and leads to "soft x-ray emissions," ("What is a Solar Flare?").

The impulsive stage is characterized by the acceleration of protons and electrons, and the decay stage is the gradual build up and decay of soft x-rays ("What is a Solar Flare?"). All three stages together can last between a few seconds to an hour and occur before a coronal loop forms on the surface ("What is a Solar Flare?"). The March 13, 1989 CME resulted in stunning auroras that could be seen as far south as Cuba, according to Hadhazy.

Solar flares usually tend to affect regions closer to the arctic because of the "frequent ground currents in northern latitudes," (Hadhazy). No matter how stunning the light display, the CME did adversely affect satellites orbiting the Earth and also crashed a.