What is antimatter?
To understand the basics of antimatter
WHAT IS ANTIMATTER?
Antimatter is exactly what you might think it
is -- the opposite of normal matter, of
which the majority of our universe is made.
These anti-particles are, literally, mirror
images of normal matter. Each anti-particle
has the same mass as its corresponding
particle, but the electrical charges are
Positrons - Electrons with a positive instead of
negative charge. Discovered by Carl Anderson in 1932,
positrons were the first evidence that antimatter
Anti-protons - Protons that have a negative instead of
the usual positive charge. In 1955, researchers at the
Berkeley Bevatron produced an antiproton.
Pairing together positrons and antiprotons, scientists
at CERN, the European Organization for Nuclear
Research, created the first anti-atom. Nine anti-
hydrogen atoms were created, each lasting only 40
nanoseconds. As of 1998, CERN researchers were
pushing the production of anti-hydrogen atoms to
2,000 per hour.
HYDROGEN AND ANTIHYDROGEN
When antimatter comes into contact with normal
matter, these equal but opposite particles collide
to produce an explosion emitting pure radiation,
which travels out of the point of the explosion at
the speed of light. Both particles that created the
explosion are completely annihilated, leaving
behind other subatomic particles. The explosion
that occurs when antimatter and matter interact
transfers the entire mass of both objects into
energy. Scientists believe that this energy is more
powerful than any that can be generated by other
100% EFFICIENT PROCESS !
Ideal energy density for chemical reactions is 1
x 10 7 (10^7) J/kg, for nuclear fission it is 8 x
10 13 (10^13) J/kg and for nuclear fusion it is 3
x 10 14 (10^14) J/kg, but for the matter-
antimatter annihilation it is 9 x 10 16 (10^16)
J/kg. This is 10 10 (10 billion) times that of
conventional chemical propellants. This
represents the highest energy release per unit
mass of any known reaction in physics. The
reason for this is that the annihilation is the
complete conversion of matter into energy ,
rather than just the part conversion that occurs
in fission and fusion.
One of einstein’s greatest insight was to realize
that matter and energy are actually diferent
forms of the same thing . Matter can be
turned in to energy and energy in to matter .
Einstein’s formula tells us the amount of
energy a particular amount of matter will be
equivalent to if it is suddenly converted in to
energy . This is what happens in annihilation.
The amount of energy released can be
calculated using einstein’s formula e=mc2.
E=energy released by annihilation
M=mass of the particles get annihilated
C=speed of light in vaccuum
HOW IT BECOMES A
Antimatter study becomes extremely important
as the energy released during annihilation of
matter and antimatter can be used to meet
our energy requirements . Scientists in
famous research facilities are working on to
make an effective way to use energy released
through annihilation for various purposes and
also a safe facility to store antimatter in
considerable quantities so that it can be used.
There is technology available to create
antimatter through the use of high-energy
particle colliders, also called "atom
smashers." Atom smashers, like CERN, are
large tunnels lined with powerful super
magnets that circle around to propel atoms at
near-light speeds. When an atom is sent
through this accelerator, it slams into a target,
creating particles. Some of these particles are
antiparticles that are separated out by the
These high-energy particle
accelerators only produce one or two
picograms of antiprotons each year.
A picogram is a trillionth of a gram.
All of the antiprotons produced at
CERN in one year would be enough to
light a 100-watt electric light bulb
for three seconds.
Most expensive substance on
The highly complex and sophisticated nature
of artificial production of antimatter has
made it the most expensive substance on
earth. In 1999,the estimated cost for 1 gram
of antimatter was about $62.5 trillion !!!
It is possible that particles outnumbered anti-
particles at the time of the Big Bang. As stated
above, the collision of particles and anti-particles
destroys both. And because there may have been
more particles in the universe to start with, those
are all that's left. There may be no naturally-
existing anti-particles in our universe today.
However, scientists discovered a possible deposit
of antimatter near the center of the galaxy in
1977. If that does exist, it would mean that
antimatter exists naturally, and the need to make
our own antimatter would be eliminated.
Antiparticles have either a positive or a
negative electrical charge, so they can
be stored in what we call a trap which
has the appropriate configuration of
electrical and magnetic fields to keep
them confined in a small place. Of
course, this has to be done in good
vacuum to avoid collisions with matter
particles. Antiatoms are electrically
neutral, but they have magnetic
properties that can be used to keep
them in "magnetic bottles".
APPLICATION OF ANTIMATTER
Particle physicists regularly use collisions between electrons and
their antiparticles, positrons, to investigate matter and fundamental
forces at high energies.
When electron and positron meet, they annihilate, turning into energy
which, at high energies, can rematerialize as new particles and
antiparticles. This is what happens at machines such as the Large
Electron Positron (LEP) collider at CERN.
At low energies, however, the electron-positron annihilations can be put
to different uses, for example to reveal the workings of the brain in the
technique called Positron Emission Tomography (PET) . In PET, the
positrons come from the decay of radioactive nuclei incorporated in a
special fluid injected into the patient. The positrons then annihilate with
electrons in nearby atoms. As the electron and positron are almost at
rest when they annihilate, there is not enough annihilation energy to
make even the lightest particle and antiparticle (the electron and the
positron), so the energy emerges as two gamma rays, which shoot off in
opposite directions to conserve momentum.
Antimatter as a propulsion
if we are enable to develop a propulsion system which
uses antimatter as the source of energy in the future
it will surely render any other Newtonian rocket
obsolete overnight, the system has the highest
predicted efficiency, specific impulse and probably
the highest thrust to weight ratio. There does seem
to be a serious amount of disagreement over this last
point, the general feeling seems to be that the thrust
to weight will at least comparable to today's very
powerful chemical rockets. What this means is that
only 100 milligrams (1/10 gram) of antimatter would
be needed to match the total propulsive energy of the
Space Shuttle (all those huge tanks of fuel!).
Antimatter propulsion system
There are actually two choices for propulsion.
Well electron-positron annihilation produces
high energy gamma rays which are
impossible to control, hence useless for
propulsion, and on top of this are potentially
very dangerous. Whereas the proton-
antiproton annihilation produces charged
particles (mostly pions moving at velocities
close to that of light) that can be directed
with magnetic fields, maximizing propellant
JOURNEY TIME OF AN
Estimates for travel times to Mars for an
advanced antimatter rocket are anywhere
from 24 hours to 2 weeks, it is probable that
it will be somewhere in between. Compare
this to the space shuttle using its
conventional chemical propulsion when a trip
to Mars would take between 1 and 2 years !!!
Antimatter indeed has the potential of
becoming the most efficient source of energy.
But as the artificial production of antimatter
has made it the most expensive substance on
earth , we still have to wait until we find it
naturally . In sometime in future we can hope
that we will be capable of travelling anywhere
inside our galaxy with the help of antimatter