THE FUNDAMENTALS OF PHYSICSSCIENCEPHOTO^ LIBRARY5 While the experiments involving
the LHC can show what particles were
prevalent in the primordial Universe,
theoreticians then have to form a
theory to understand them.
St ring t heor y is a possible qua ntum
t heor y of gravity, but it is unclea r
whether it bears any resemblance to
reality, because the mathematics are
currently unable to predict anything
that can be tested in a lab or observed.
For now, the moment of the Big Bang
remains terra incognita.
CHAPTER 2: INFLATION
10-35 seconds after the Big Bang
Until the Planck probe, almost every
observation of the Universe’s largest
scales had suggested that it is almost
uniform. Sure, there are clusters of
galaxies and huge voids, but even
these are comparatively small when
the Universe is considered as a whole.
As a result, cosmologists had
developed a mathematical framework
called inflation to explain the
uniformity. First proposed in 1980 byAlan Guth, a particle physicist from
the Massachusetts Institute of
Technology, it postulated that, right
after the Big Bang, a period of
extraordinary expansion took place.
In the blink of an eye, the Universe
grew by a factor of at least 1,060. This
would smooth out any large-scale
deviation across the Universe, making
it appea r unifor m. Only t he smallest
fluctuations in the density of matter
and energy would remain, the
cosmologists theorised. Remarkably,
these fluctuations were found in 1989
by NASA’s Cosmic Background
Explorer (COBE) satellite and they
amount to no more than one part in
100,000. They are the seeds from
which the galaxies have grown.
The Planck probe measured these
fluctuations in greater detail. It split
the sky into an image made up of a
billion pixels and observed each one a
thousand times during its three-year
mission. This produced a map of the
sea of microwaves that bathe space- the cosmic microwave background
(CMB) – unlike anything that had
been seen before.
It’s these subtle fluctuations in this
radiation left over from the Big Bang
that provide astronomers with their
blueprint of the early Universe – the
distribution of matter and energy a
fraction of a second after the Big Bang.
As soon as t he data f rom Pla nck was
released, problems appeared that the
cosmological community are still
attempting to solve.
For example, there is a suspiciously
large cold spot, which suggests that a
vast clump of matter was present in
the early Universe and it’s much
denser than inflation can explain.
More t roubling is t hat one side of t he
Universe has fluctuations that appear
stronger than the other, indicating an
uneven dist ribution of matter across
the expanse of space.
“This is very strange,” says Dr
George Efstathiou, Professor of
Astrophysics at the University of
Cambridge and a member of the
Planck science team. “I think that if
t here really is a ny t hing to t his, you
have to question how t hat f its in wit h
inflation. It’s really puzzling.”
The fundamental elements of the
Universe burst out from the Big Bang
(bottom). As they spread, and cooled,
they gradually coalesced to form the
planets and galaxies we know today