Page 6 - Curriculum Visions Dynamic Book

Hydrogen in the stars
The Sun is made mainly of hydrogen. Burning hydrogen is the source of sunlight and all other starlight.
The Sun’s immense gravitational force pulls its hydrogen atoms together, and by a process called fusion, helium is formed and energy released. Thus, hydrogen is used as the fuel in the Sun.
Fusion is the most powerful reaction in the Universe. People have copied it to make thermonuclear (hydrogen) bombs. The conversion of hydrogen makes the Sun intensely hot and releases vast amounts
of energy to space as radiation.
A small fraction of this radiation
reaches Earth as sunlight, the visible rays
of the spectrum, but more radiation reaches
the Earth as ultraviolet light, infra-red light and a variety of other wavelengths of radiation that
we cannot actually see. In this way nuclear fusion reactions in the Sun make possible life on Earth.
Fusion: combining hydrogen atoms
Nuclear fusion is the forcing together, or fusing, of two atoms to produce an even heavier atom. When fusion occurs there is an enormous release of energy.
Fusion has proved to be one of the most difficult processes for scientists
to achieve artificially, and yet it is one
of the most common features of the Universe. The reason fusion is so difficult is that enormously high temperatures and great pressures are needed. In
the stars both of these conditions are naturally present. So getting fusion going on Earth is nothing short of making stars.
Pollution-free radiation
Fusion does not create any radioactive pollution. It is not a chain reaction like fission and so cannot
run out of control and cause a massive explosion. Thus the present generation of nuclear reactors is
just a temporary step on the way to the goal of clean, safe nuclear energy. This is why countries need to pursue nuclear technology, so that they do not fall behind and can really benefit from the development of fusion power when it comes.
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