The U.S. Air Force is quietly spending millions of dollars
investigating ways to use a radical power source -- antimatter, the eerie
"mirror" of ordinary matter -- in future weapons.
The most powerful potential energy source presently thought to be
available to humanity, antimatter is a term normally heard in science-fiction
films and TV shows, whose heroes fly "antimatter-powered spaceships" and do
battle with "antimatter guns."
But antimatter itself isn't fiction; it actually exists and has been
intensively studied by physicists since the 1930s. In a sense, matter and
antimatter are the yin and yang of reality: Every type of subatomic particle
has its antimatter counterpart. But when matter and antimatter collide, they
annihilate each other in an immense burst of energy.
During the Cold War, the Air Force funded numerous scientific studies of
the basic physics of antimatter. With the knowledge gained, some Air Force
insiders are beginning to think seriously about potential military uses --
for example, antimatter bombs small enough to hold in one's hand, and
antimatter engines for 24/7 surveillance aircraft.
More cataclysmic possible uses include a new generation of super weapons
-- either pure antimatter bombs or antimatter-triggered nuclear weapons; the
former wouldn't emit radioactive fallout. Another possibility is antimatter-
powered "electromagnetic pulse" weapons that could fry an enemy's electric
power grid and communications networks, leaving him literally in the dark and
unable to operate his society and armed forces.
Following an initial inquiry from The Chronicle this summer, the Air
Force forbade its employees from publicly discussing the antimatter research
program. Still, details on the program appear in numerous Air Force documents
distributed over the Internet prior to the ban.
These include an outline of a March 2004 speech by an Air Force official
who, in effect, spilled the beans about the Air Force's high hopes for
antimatter weapons. On March 24, Kenneth Edwards, director of the
"revolutionary munitions" team at the Munitions Directorate at Eglin Air Force
Base in Florida was keynote speaker at the NASA Institute for Advanced
Concepts (NIAC) conference in Arlington, Va.
In that talk, Edwards discussed the potential uses of a type of
antimatter called positrons.
Physicists have known about positrons or "antielectrons" since the early
1930s, when Caltech scientist Carl Anderson discovered a positron flying
through a detector in his laboratory. That discovery, and the later discovery
of "antiprotons" by Berkeley scientists in the 1950s, upheld a 1920s theory of
antimatter proposed by physicist Paul Dirac.
In 1929, Dirac suggested that the building blocks of atoms -- electrons
(negatively charged particles) and protons (positively charged particles) --
have antimatter counterparts: antielectrons and antiprotons. One fundamental
difference between matter and antimatter is that their subatomic building
blocks carry opposite electric charges. Thus, while an ordinary electron is
negatively charged, an antielectron is positively charged (hence the term
positrons, which means "positive electrons"); and while an ordinary proton is
positively charged, an antiproton is negative.
The real excitement, though, is this: If electrons or protons collide
with their antimatter counterparts, they annihilate each other. In so doing,
they unleash more energy than any other known energy source, even
thermonuclear bombs.
The energy from colliding positrons and antielectrons "is 10 billion
times ... that of high explosive," Edwards explained in his March speech.
Moreover, 1 gram of antimatter, about 1/25th of an ounce, would equal "23
space shuttle fuel tanks of energy." Thus "positron energy conversion," as he
called it, would be a "revolutionary energy source" of interest to those who
wage war.
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