The Sun, the original source of all forms of energy on Earth seems quite peaceful when viewed from our dear planet Earth. But, actually, a lot of commotion is going on over there.

Each second, a lot of activities including explosions, nuclear reactions, and chemical reactions take place on this ball of fire. One such important activity which has grabbed the attention of the scientists over the past few years, is a typical kind of behaviour known as solar flares.

Well, obviously such a ball of fire should have fiery flares, shouldn't it? But the solar flare theory is not just about the blazing flares of the sun. Let's find out more about this phenomenon (remarkable happening).

What, when and where

In general terms, a solar flare can be defined as a sudden, intense variation in the Sun's brightness which results due to the high amount of energy released during an explosion.

A solar flare is emitted (sent out) as a result of the magnetic energy accumulated (gathered) on the Sun's atmosphere being released. When energy is released this way, electromagnetic radiation of all the electromagnetic waves in the electromagnetic spectrum take place.

That means, electromagnetic waves ranging from low frequency radio waves to high frequency gamma rays are emitted from the Sun in this instance.

Solar flares occur in the corona and the chromosphere of the Sun. The corona is the outermost part of the Sun's atmosphere and the chromosphere resides below the corona and above the photosphere.

The massive heat generated go up to millions of degrees Kelvin accelerate electrons, protons and ions, to a speed of nearly that of light and these are what give rise to electromagnetic radiation.

The Japanese sent a spacecraft called 'Solar-B' in September 2006 to obtain more details about the magnetic fields which trigger solar flares.

Importance and hazards

Studying solar flares is important in trying to understand other energy releasing phenomena such as flare stars, and black holes. But, it is more important to identify their effects on Earth and outer space.

Solar flares may ionize earth's upper atmosphere which expands it, and this would directly disturb the orbits of the satellites around due to the increased drag on the satellites.

Long distance radio signals can be disrupted and electronic components of satellites may get damaged. A dangerous outcome of solar flares is that they release high energy particles known as the 'proton storm'.

These particles can even go through the human body and create biochemical damage. This has become a key concern in manned missions in other planets and astronauts working in space.

Fact File

* The first solar flare was witnessed on September 1, 1859 by two scientists, Richard C. Carrington and Richard Hodgson.

* The energy released in a flare can be as immense as millions of 100 megaton hydrogen bombs exploding at the same time.

* The average energy released in a solar flare is generally of the order 1027 ergs. An erg is a unit of measuring energy which is equal to 1x10-7 joules (electricity unit of work or energy).

* The maximum energy released by a flare can go as high as 1032 ergs which is about 1/10 of the total energy emitted by the Sun every second.

* The temperature inside a flare is generally 20 to 30 million degrees Kelvin and may even reach up to 100 million degrees Kelvin too.

(1K = 10C + 273.15)

Solar flares can be considered as the most energetic explosions in the solar system.

Compiled by Aravinda Dassanayake