The Mahdi Times The Mahdi Times, Issue #22, September 2014 | Page 12

it matches the job of the
cosmological constant in
gravity’s counteraction of
matter and energy.

hyperbolic paraboloid or a
horse saddle, and if it is
expanding, its expansion will
continue forever.

Afterwards, three models of an
unsteady universe were
completed, commonly referred
to as the Friedmann models.
This opened the door to the
expanding universe, which has
a beginning. The Friedmann
models had predicted that the
universe is expanding before
Edwin Hubble used the results
of galaxy observations to
discover that the frequency of
light that galaxies emit shifts
toward the color red, and this
shift increases the further away
they are. According to the
doppler effect, this means they
are moving away from each
other at an increasing rate.

The third model: The curvature
of the universe is zero, or let’s
say it is flat. If it is expanding,
its rate of expansion will slow
down, approaching but never
actually reaching zero. This
means it will slow down, but
never completely stop
expanding. In this type of
universe, the positive energy
provided by matter equals the
negative energy provided by
gravity.

The Friedmann models are:
The first model: The curvature
of the universe is positive like
the surface of a sphere, and if it
is expanding, it will eventually
contract due to gravity, and its
expansion will not continue
forever.
The second model: The
curvature of the universe is
negative like the surface of a

All Friedmann models predict
that at the beginning of the
universe, the distance between
the galaxies was zero, meaning
the size of the universe was
zero and its density was infinite.
This means that the Friedmann
models built on the theory of
relativity state that the universe
started from a point at which
the theory of general relativity
itself collapses. This point is
called a point of singularity, at
which the big bang began.