By Anant Srivastava
Introduction
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.
Conclusion
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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