In the year 1859, scientists Richard Carrington and Richard Hodgson observed and reported a large flare on the surface of the sun. Although the reason and the nature of the observation was not apparent at that moment, it became known as a ‘solar flare’. However, with modern technology, scientists are able to clearly describe what a solar flare is and how devastating such flares can be, if it reaches the earth’s atmosphere.
According to the National Aeronautics and Space Administration (NASA), a solar flare is an ‘intense burst of radiation coming from the release of magnetic energy associated with sunspots’. These flares can last from few minutes to hours and NASA believes that these are the largest explosive events taking place in the solar system.
When trying to resolve the mystery of solar flares, scientists have uncovered that the solar atmosphere contains huge magnetic loops known as ‘prominences.’ When these loops touch each other, it can short-circuit and the result would be an explosion, which scientists describe as a ‘solar flare’. The amount of energy released at the time of such an explosions is equivalent to millions of 100-megaton hydrogen bombs exploding at the same time or around 10 million times greater than a volcanic explosion. As the explosion take place, the released energy heats up and accelerates particles such as electrons, protons and heavy nuclei present in the solar atmosphere.
When a solar flare occurs, it happens in three distinct stages. The first stage, known as the ‘precursor’ stage is where the release of magnetic energy takes place. During this stage, soft x-rays are emitted and can be detected. The second stage is the ‘impulsive’ stage in which the protons and electrons are heated and accelerated to powerful energies. During this stage, high intensity radiation will be emitted and these include hard x-rays, gamma rays and radio waves. The last stage or the ‘decay’ stage is characterized by the gradual build-up and the decay of the soft x-rays. According to scientists, these stages can last from few seconds to even an hour, although observed solar flares have not exceeded the norm so far.
The number of solar flares visible on the sun varies depending on the solar cycle. Thus, it is expected that the maximum number of solar flares will take place in eleven-year cycles and by 2011/2012, the sun should have reached a maximum cycle.
As most of the radiations emitted from a solar flare do not reach the earth as it is blocked by the Earth’s atmosphere, scientists use special cameras located in the space to measure these energetic waves. However, scientific equipment, which can detect radiation signatures mounted on the earth, can visualize the radio and optical emissions from the solar flares. At the same time, it should be remembered that the energy and the particles released by a solar flare could damage or corrode the manmade structures sent to the outer space, or even harm the astronauts in the space.
Lastly, solar flares cannot be seen to the naked eye and one should not even try such things as direct visualization of the sun’s rays, because they may cause harm to the delicate layer inside the human eye.