Page 195 - For Men of Understanding

If the
atmosphere
did not have a
protective
shield, the
earth would
be left
defenceless
against
showers of
meteors.
turn away from Our signs." (Surat al-Anbiya: 32)
One of the most important indications that the sky is "a preserved and pro-
tected roof" is the magnetic field surrounding the earth. The top layer of the
atmosphere is made up of a magnetic zone called the "Van Allen Belt". This
zone is formed by the qualities of the earth’s core.
The core of the earth contains heavy magnetic elements like iron and nick-
el. What is more important, however, is that the core is composed of two dis-
tinct structures. The inner core is solid while the outer core is liquid. The outer

layer floats on top of the inner layer, creating a magnetic effect on heavy met-
als, which in turn forms a magnetic field. The Van Allen Belt is an extension of
this magnetic zone reaching the outer layer of the atmosphere. This magnetic
field shields the earth against possible dangers from space.
One of the most serious of these dangers is the "solar winds". Apart from
heat, light and radiation, the sun sends the earth a wind made up of protons
and electrons moving at a speed of 1.5 million kilometres per hour.
Solar winds cannot pass through the Van Allen Belts, which create magnet-
ic fields at a distance of 40,000 miles from the earth. When the solar wind, in
the form of a rain of particles, runs into this magnetic field, it decomposes and
flows around this field.
The atmosphere absorbs most of the X-rays and ultraviolet rays emitted by
the sun. Without this absorption, life on earth would be impossible.
The atmospheric zones surrounding us only let harmless rays, radio waves,
and visible light reach the earth. If our atmosphere did not have such imper-

meability, we could neither use radio waves for communication nor have day-

The Earth 193