PHRSERS AND DERTH STARS 43
ENERGY FOR A DEATH STAR
To create a Death Star laser cannon that can destroy an entire planet
and terrorize a galaxy, such as that described in Star Wars, one would
need to create the most powerful laser ever conceived. At present some
of the most powerful lasers on Earth are being used to unleash temperatures found only in the center of stars. In the form of fusion reactors, they might one day harness the power of the stars on Earth.
Fusion machines try to mimic what happens in outer space when
a star first forms. A star begins as a huge ball of formless hydrogen gas,
until gravity compresses the gas and thereby heats it up; temperatures
eventually reach astronomical levels. Deep inside a star's core, for example, temperatures can soar to between 50 million and 100 million
degrees centigrade, hot enough to cause hydrogen nuclei to slam into
each other, creating helium nuclei and a burst of energy. The fusion of
hydrogen into helium, whereby a small amount of mass is converted
into the explosive energy of a star via Einstein's famous equation
E = mc
2 , is the energy source of the stars.
There are two ways in which scientists are currently attempting to
harness fusion on the Earth. Both have proven to be much more difficult to develop than expected.
INERTIAL CONFINEMENT FOR FUSION
The first method is called "inertial confinement." It uses the most powerful lasers on Earth to create a piece of the sun in the laboratory. A
neodymium glass solid-state laser is ideally suited to duplicate the
blistering temperatures found only in the core of a star. These laser
systems are the size of a large factory and contain a battery of lasers
that shoot a series of parallel laser beams down a long tunnel. These
high-power laser beams then strike a series of small mirrors arranged
around a sphere; the mirrors carefully focus the laser beams uniformly onto a tiny, hydrogen-rich pellet (made of substances such as
ENERGY FOR A DEATH STAR
To create a Death Star laser cannon that can destroy an entire planet
and terrorize a galaxy, such as that described in Star Wars, one would
need to create the most powerful laser ever conceived. At present some
of the most powerful lasers on Earth are being used to unleash temperatures found only in the center of stars. In the form of fusion reactors, they might one day harness the power of the stars on Earth.
Fusion machines try to mimic what happens in outer space when
a star first forms. A star begins as a huge ball of formless hydrogen gas,
until gravity compresses the gas and thereby heats it up; temperatures
eventually reach astronomical levels. Deep inside a star's core, for example, temperatures can soar to between 50 million and 100 million
degrees centigrade, hot enough to cause hydrogen nuclei to slam into
each other, creating helium nuclei and a burst of energy. The fusion of
hydrogen into helium, whereby a small amount of mass is converted
into the explosive energy of a star via Einstein's famous equation
E = mc
2 , is the energy source of the stars.
There are two ways in which scientists are currently attempting to
harness fusion on the Earth. Both have proven to be much more difficult to develop than expected.
INERTIAL CONFINEMENT FOR FUSION
The first method is called "inertial confinement." It uses the most powerful lasers on Earth to create a piece of the sun in the laboratory. A
neodymium glass solid-state laser is ideally suited to duplicate the
blistering temperatures found only in the core of a star. These laser
systems are the size of a large factory and contain a battery of lasers
that shoot a series of parallel laser beams down a long tunnel. These
high-power laser beams then strike a series of small mirrors arranged
around a sphere; the mirrors carefully focus the laser beams uniformly onto a tiny, hydrogen-rich pellet (made of substances such as