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Ordinary matter has negatively charged electrons circling a
positively charged nuclei. Anti-matter has positively charged electrons
- positrons - orbiting a nucleI with a negative charge - anti-protons.
Only anti-protons and positrons are able to be produced at this time,
but scientists in Switzerland have begun a series of experiments which
they believe will lead to the creation of the first anti-matter element
-- Anti-Hydrogen.
The Research
Early scientists often made two mistakes
about anti-matter. Some thought it had a negative mass, and would thus
feel gravity as a push rather than a pull. If this were so, the
antiproton's negative mass/energy would cancel the proton's when they
met and nothing would remain; in reality, two extremely high-energy
gamma photons are produced.
Today's theories of the universe say that
there is no such thing as a negative mass. The second and more subtle
mistake is the idea that anti-water would only annihilate with ordinary
water, and could safety be kept in (say) an iron container. This is not
so: it is the subatomic particles that react so destructively, and
their arrangement makes no difference.
Scientists at CERN in Geneva are
working on a device called the LEAR (low energy anti-proton ring) in an
attempt to slow the velocity of the anti-protons to a billionth of
their normal speeds. The slowing of the anti-protons and positrons,
which normally travel at a velocity of that near the speed of light, is
neccesary so that they have a chance of meeting and combining into
anti-hydrogen.
The problems with research in the field of anti-matter
is that when the anti-matter elements touch matter elements they
annihilate each other. The total combined mass of both elements are
released in a spectacular blast of energy. Electrons and positrons come
together and vanish into high-energy gamma rays (plus a certain number
of harmless neutrinos, which pass through whole planets without
effect).
Hitting ordinary matter, 1 kg of anti-matter explodes with the
force of up to 43 million tons of TNT - as though several thousand
Hiroshima bombs were detonated at once. So how can anti-matter be
stored? Space seems the only place, both for storage and for
large-scale production. On Earth, gravity will sooner or later pull any
anti-matter into disastrous contact with matter. Anti-matter has the
opposite effect of gravity on it, the anti-matter is 'pushed away' by
the gravitational force due to its opposite nature to that of matter.
A
way around the gravity problem appears at CERN, where fast moving
anti-protons can be held in a 'storage ring' around which they
constantly move - and kept away from the walls of the vacuum chamber -
by magnetic fields. However, this only works for charged particles, it
does not work for anti-neutrons, for example.
The Unanswerable Question
Though anti-matter can be manufactured, slowly, natural anti-matter has
never been found. In theory, we should expect equal amounts of matter
and anti-matter to be formed at the beginning of the universe - perhaps
some far off galaxies are the made of anti-matter that somehow became
separated from matter long ago.
A problem with the theory is that
cosmic rays that reach Earth from far-off parts are often made up of
protons or even nuclei, never of anti-protons or antinuclei. There may
be no natural anti-matter anywhere. In that case, what happened to it?
The most obvious answer is that, as predicted by theory, all the matter
and anti-matter underwent mutual annihilation in the first seconds of
creation; but why there do we still have matter? It seems unlikely that
more matter than anti-matter should be formed. In this scenario, the
matter would have to exceed the anti-matter by one part in 1000
million.
An alternative theory is produced by the physicist M.
Goldhaber in 1956, is that the universe divided into two parts after
its formation - the universe that we live in, and an alternate universe
of anti-matter that cannot be observed by us.
The Chemistry
Though they
have no charge, anti-neutrons differ from neutrons in having opposite
'spin' and 'baryon number'. All heavy particles, like protons or
neutrons, are called baryons. A firm rule is that the total baryon
number cannot change, though this apparently fails inside black holes.
A neutron (baryon number +1) can become a proton (baryon number +1) and
an electron (baryon number 0 since an electron is not a baryon but a
light particle). The total electric charge stays at zero and the total
baryon number at +1. But a proton cannot simply be annihilated. A
proton and anti-proton (baryon number -1) can join together in an
annihilation of both.
The two heavy particles meet in a flare of energy
and vanish, their mass converted to high-energy radiation wile their
opposite charges and baryon numbers cancel out. We can make antiprotons
in the laboratory by turning this process round, using a particle
accelerator to smash protons together at such enormous energies that
the energy of collision is more than twice the mass/energy of a proton.
The resulting reaction is written:
p + p p + p + p + p
Two protons (p) become three protons plus an
antiproton(p); the total baryon number before is: 1 + 1 = 2 And after
the collision it is: 1 + 1 + 1 - 1 = 2 Still two. Anti-matter elements
have the same properties as matter properties. For example, two atoms
of anti-hydrogen and one atom of anti-oxygen would become anti-water.
The Article
The article chosen reflects on recent advancements in
anti-matter research. Scientists in Switzerland have begun
experimenting with a LEAR device (low energy anti-proton ring) which
would slow the particle velocity by a billionth of its original
velocity. This is all done in an effort to slow the velocity to such a
speed where it can combine chemically with positrons to form
anti-hydrogen. The author of the article, whose name was not included
on the article, failed to investigate other anti-matter research
laboratories and their advancements.
The author focused on the CERN
research laboratory in Geneva. 'The intriguing thing about our work is
that it flies in the face of all other current developments in particle
physics' . The article also focused on the intrigue into the
discovering the anti-matter secret, but did not mention much on the
destruction and mayhem anti-matter would cause if not treated with the
utmost care and safety.
Discovering anti-matter could mean the end of
the Earth as we know it, one mistake could mean the end of the world
and a release of high-energy gamma rays that could wipe out the life on
earth in mere minutes. It was a quite interesting article, with a lot
of information that could affect the entire world. The article,
however, did not focus on the benefits or disadvantages of anti-matter
nor did it mention the practical uses of anti-matter. They are too
expensive to use for powering rocket ships, and are not safe for
household or industrial use, so have no meaning to the general public.
It is merely a race to see who can make the first anti-matter element.
As research continues into the field of anti-matter there might be
some very interesting and practical uses of anti-matter in the society
of the future. Until there is a practical use, this is merely an
attempt to prove which research lab will be the first to manufacture
the anti-matter elements.
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