Page 28 - The Little Man in the Tower

The Little Man in the Tower

of the cosmic background radiation—energy left over from the "Big Bang,"
the explosion by which the universe was created. The word "sound" here
refers to the perception that forms in our brains after our radios have
transformed these waves into vibrations in the air that our ears can hear.

Photons, the source of the perception we refer to as "light," are much
lighter particles that usually bounce back from the first molecule they
encounter. In doing so, they do almost no damage to the place they strike.
Due to their frequencies—the speed at which they vibrate—ultra-violet rays
are charged with greater energy and can penetrate more deeply into our skin,
sometimes damaging the cells’ genetic codes. This is why excessive
exposure to the Sun’s rays can lead to skin cancer.

Those photons known as infra-red because of their frequencies leave
some of their energy behind, increasing the speed of vibration of the atoms
there—in other words, the heat on the surface they strike. For this reason,
infra-red rays are also called as heat rays. A burning coal stove or an electric
heater give off large amounts of infra-red radiation, which is "seen" or
rather, perceived, by our bodies as heat.

10 nm 10 nm 700 nm 600 nm500 nm 400 nm10 nm 10 nm 10 nm
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-2
2
10
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infra-red rays unltra-violet raysx rays

Our eyes can perceive only those light rays falling on the spectrum between
ultraviolet and infrared.

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