In the
whole universe, everywhere we see two types of processes. Either expansion or
contraction. Let we first take example of living organisms. They first grow up
(expand) then rotten (contract). If you see a rotten fruit using speed
photography, it contracts and emits gases and other elements (expansion).
Sometime rotten and putrid things bloat (expand) instead of contracting; and
many living things become smaller as they grow. Insect Larvae are a prime
example.
At macro level, stars after its birth expand. Once the hydrogen fuel
at the core is exhausted, a star of at least 0.4 times the mass of the Sun
expands to become a red giant. This is the process of expansion and then
sometime ends on black holes; a process of contraction, though most stars in
the universe end up as white dwarves which ultimately become brown dwarves. All
these are the examples of expansion – contraction.
Stars
that begin with more than 50 solar masses can lose over half their total mass
while they remain on the main sequence. This is process of contraction in term
of mass.
Stars of
at least 0.4 solar masses exhaust their supply of hydrogen at their core, their
outer layers expand and cool to form a red giant. It is expansion
in terms of volume.
In a red
giant of up to 2.25 solar masses, hydrogen fusion proceeds in a shell-layer
surrounding the core. Eventually the core is compressed enough to start helium
fusion, and the star now gradually shrinks in radius and increases its surface
temperature, which is a process of contraction.
In this
way we can form an hypothesis that our universe will contract after the current
process of expansion. And then again it will be converted into a small point as
it was in beginning before the big bang.
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