Solar flare and Earth's magnetic field.
A recent NASA report shows that a solar flare is heading towards
Earth. It could disrupt power grids, GPS and airline flights. It is the
highest in the last five years which shakes the Earth magnetic field.
Scientists say such storms don't pose a threat to people, just
technology. What is a solar flare?
A flare is a sudden, rapid and
intense variation in brightness. A solar flare occurs when magnetic
energy that has been built up in solar atmosphere suddenly released. The
amount of energy releases is equivalent to the millions of hydrogen
bombs exploding at the same time. The first solar flare recorded was on
September 1, 1859.
As the magnetic energy is being released
particles, including electrons, protons and heavy ions of a hot plasma
are accelerated in the solar atmosphere. There are typically three
stages of a solar flare. First is the precursor stage where the magnetic
energy is triggered. Soft x-ray emissions are detected in this stage.
The second is the impulsive stage, when plasma jets are accelerated to
energies exceeding 1 MeV. During impulsive stage, radio waves, hard
x-rays and gamma rays are emitted. Finally, the third stage is the decay
stage, when soft x-rays can be detected. The duration of these stages
can be as short as a few seconds or as long as an hour.
Solar
flare extend out to the layer of the Sun is called the Corona. The
Corona is the outermost atmosphere of the sun. It is hot plasma which is
the ionized state of matter. 99% of matter in the universe is in
plasma state which is the fourth state of matter. The other states are:
solid, liquid and gas. The temperature of the hot plasma is in the order
of a few million degrees of Kelvin. The Corona is not uniformly bright.
The bright loops are connected with the strong magnetic areas which are
called active regions. Sunspots are located within these active
regions. Solar flare occurs in the active regions.
The frequency
of solar flare coincides with the Sun's eleven years cycle. The radio
and optical emissions from flares can be observed with telescopes on the
Earth. Energetic emissions such as x-rays and gamma rays require
telescopes to be placed in space since these emissions do not penetrate
Earth's atmosphere.
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