Australian Science Illustrated – Issue 51 2017

billions of dollars annually, but so far, no
results have been produced. However, it now
looks as if the LHC and other prestigious
megaprojects have been outcompeted by a
small team of scientists armed with a
"simple" small particle detector.

THE FIFTH FORCE OF NATURE?
So far, physicists have not been able to prove
the existence of dark matter, as the matter
cannot be observed directly. But scientists
can still measure the matter’s influence on

the visible universe, and they are convinced

that dark matter is the missing link that can

pave the way for a theory of everything,

which also includes the fourth known force of

nature, gravity. The standard model cannot

explain gravity, unless the dark particles are

introduced into the theory. Galaxies such as

the Milky Way are rotating so fast that the

stars would be hurled in all directions, if a

large quantity of invisible matter did not hold

them in their orbits by means of gravity.

Astronomers need the dark matter in order to

explain why galaxies behave the way they do.

All known forces of nature have specific

force carriers, which mediate the forces'

ranges. The Hungarian scientists believe that

the dark force particle works between the

building blocks of dark matter in the same

way as the electromagnetic force works in

the visible universe. The electromagnetic

force functions via exchange of light

particles – photons – which are the driving

forces behind all chemical, magnetic, and

electric reactions in the universe. The dark

A collision between two galaxy

clusters produced the Musket

Ball Cluster. The galaxies were spread

across a large region, whereas gas

clouds gathered in the central

collision area.

Measurements of the galaxy

cluster show that the majority of

its mass was not in the same place as

the galaxies and the gas clouds after

the collision. The mass must come from

invisible dark matter.

The conversion into a

proton results in the

emission of an electron and

an antineutrino.

(^12)
A neutron is converted
into a proton in the atomic
nucleus, and the caesium atom
turns into barium.
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2
THE WEAK NUCLEAR FORCE GRAVITY
Weak force causes
radioactive decay
Gravity holds the
galaxies together
Like the strong nuclear force,
the weak nuclear force only
functions inside atomic nuclei,
where it triggers one of a total
of three types of radioactive
decay – beta decay. The decay
takes place, when the weak
nuclear force converts a
neutron into a proton. The
conversion makes the atomic
nucleus emit radiation in the
form of an electron, which is
fired at a speed close to that of
light. The weak nuclear force
has a 1,000 times shorter
range than the strong nuclear
force, and it is millions
of times weaker.
Gravity works between all
particles and bodies with
mass. The reciprocal mass
attraction is very weak
between small objects, but it
is dominant in the universe.
The range of gravity is
infinite, and so, it can
contract planets into balls
and hold huge galaxies
together. Albert Einstein’s
relativity theory very
accurately describes
gravity’s effect in the
universe, but nevertheless,
scientists are still unable to
fully explain how the well-
known force of nature works.
Decay produces
radioactive radiation
One of the effects of the weak nuclear
force is beta decay, which takes place
in caesium-137, etc.
Mass reveals dark matter
The galaxies of the universe rotate so
fast that the stars should be hurled in all
directions, unless dark matter holds
them in their orbits via gravity.
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In the atomic nucleus,
the weak nuclear force is
transmitted between
protons and neutrons by
means of W and Z particles
that only exist briefly.
Force carriers:
W AND Z
According to physicists,
mass attraction may be
due to exchange of
gravitons, but the
particle's existence has
not yet been proved.
Force carrier:
GRAVITON?
NASA
SHUTTERSTOCK
Gases
Dark matter
scienceillustrated.com.au | 33